One of my geothermal units.
One of my readers (Brian) asked the following question on the article, “Icynene-the Ultimate Barrier to High Energy Bills”:
“You mentioned geothermal in the Northeast and I am curious to see how it works in this area. I am building a house in Mass and interested in geothermal, solar, and Icynene. I know this is a discussion on Icynene, but I have some questions about Geothermal. How much did it cost to install? How big is your house? Did you run into any issues (IE Blasting ledge) and last but certainly not least, how long have you had it and have you had any maintenance issues?”
I wanted to check with my new service company (Perfection Contracting in NJ) before I wrote this post, but Brian asked in another later post, if I could respond to him as quickly as I can since he is breaking ground this week. So, on Sunday evening I am trying to answer his questions without the benefit of checking my answers with my geothermal company. If any installers have anything to add, please do since I am not an installer, but simply a homeowner who drove my installers crazy asking questions.
First, before we go any further, watch this video which explains how a geothermal system is installed and how it works:
[youtube]http://www.youtube.com/watch?v=AprORaUFwiQ&feature=related[/youtube]
Brian-My geothermal system was installed about 3 years ago. We used Water Furnace equipment to heat and cool the house, for radiant heating in the bathrooms, and for hot water through a separate geothermal hot water system. In addition a loop was set up so in the summer, hot water would be created for free because the heat of the geothermal units would “dump” into the hot water tanks.
Since we have installed our system, Water Furnace now sells more efficient units than the ones that I own. So, I can’t tell you the cost because it would not be accurate. Another house in town has geothermal, but his whole house is radiant and he uses his radiant boilers to heat his pool in the summer. If anyone is considering using their geothermal leftover heat to heat their pool in the summer make sure the water does not circulate back into the house; otherwise you could have your pool in your basement if something goes wrong.
A heat exchanger is installed in a pool house out by the pool so the pool water is heated outside rather than in your house. I need to check on the right words. As I mentioned earlier, in my haste to answer Brian, I can’t verify if this is the correct terminology without the help of my service company.
Back-up systems
Another smart idea this other homeowner implemented was to install a back-up heating system for the geothermal.
Up north, a geothermal system does not do as well when the temperature dips to 20 degrees depending on your insulation. In my case it is around ten degrees because of my Icynene insulation (open cell foam). I would imagine the better the insulation, the less likely the geothermal system would have as much trouble. When the system is having a hard time keeping up with its demands, it will go to back-up heat which is full electricity. This is an expensive stage. It is one watt to one watt electricity at that point versus 1/3 watt to 1 watt electricity other times.
I would recommend in your area to have an efficient gas or solar system that would take over before the system goes into its back-up situation or if a geothermal unit or loop fails.
Make the Units More Efficient
Since you are just breaking ground, go back to your architect and discuss if you can use a nice size 2nd floor room closet to put the 2nd floor units in. The alternative is you must put the unit in a closet in the attic which is is insulated well, including the door. (Basically, they open up part of the geothermal unit so it heats and cools itself in the closet.) These closets need to be designed so that the installer does not put the units where it is impossible to build these closets, like too close to the side of the attic near the soffits.
Your architect and installer will need to meet so your builder knows where to build the closets. Build them as you are building the house, not after the fact.The units are so much more efficient when they are in a conditioned space. I still have to build closets around my system in the attic since I was told after the fact by another installer.
In addition, I am going to spray icynene on the ducts in the attic because most installer only put R-6 on the ducts which was energy star’s requirement. The more insulated around those ducts, the better.
If I had my druthers then I would have put all my ducts, geo, etc in a conditioned space. (i.e. ducts in my first floor ceiling and units in 1st or 2nd floor closets.) I was told and I have not verified this, but energy star now wants your ducts in conditioned space. It makes perfect sense. Everything in conditioned space has to do better.
All Units in the Basement?
Another issue is since the units are in the attic; the water inside the geothermal units is pumped up to the attic so sometimes it sounds as if the wall is making a low rumbling noise.This may be due to how the pipe was attached to the framing, and was it insulated properly to reduce this noise.
Note, that only one of my units makes this noise so I suspect it was an insulation issue for that particular pipe.
My new service company told me they like all of the units in the basement and only the condensers and ducts upstairs. This is called a split system. I am not sure if you need to build closets in this situation. This split system eliminates the noise and possible water issues in the attic. Brian, it may be something for you to discuss with your installer. All units in the basement or not.
Make Sure the Units Are Set Properly
Also, when the installation is done and as dumb as this may sound, make sure your geothermal systems are set for whatever system you have. There are open and closed systems. Mine was set for a well when I in fact have a closed system.
In addition, make sure the air flow in the house is balanced the way you like it. For example, you may want more air in rooms that are used versus not used. All my units were not set properly. I think this had to do with the head of the Company passing away. I had a lot of issues because of his untimely death. I think my situation is unusual. None of these issues were due to the Water Furnace equipment but rather the installer.
Drilling
As for drilling, if I remember, I think my wells are about 300-350 feet down. I am on a hill so everyone is different. In my area, the excavation of a horizontal loop may have been more expensive than a vertical loop.
The other house that I spoke about added a few wells in case he needed them later for future expansion or something happened to one of the wells. I thought this was smart idea if you may want to add to your house or add an additional structure.
What Would I Have Done Differently?
What would I have done differently? I would have the installers set up the radiant hot water on it own geothermal boiler system and not tied it to a geothermal furnace unit. Now, if the radiant is calling for heat, the furnace has to wait to heat part of the house. It does not happen often because my first floor does not call for heat that much. I also would have installed the system as a split system and put closets in from the beginning.
Maintenance Issues
Make sure you have surge protectors on the units. They are electrical. An electrical surge could damage the units. We have outages a lot where I live and it caused a problem with one of the units.
As for maintenance, I have dampers on my second floor since a couple of the units heat some rooms and others heat other rooms. Sometimes, the dampers get stuck and the units will not shut off. (Dampers allow for one unit to heat several rooms by shutting off the heat to some rooms when they reach temperature and keeping others open until they reach desired temperature.)The damper problem has only happened with the heat.
I am not sure why this is happening, but my second damper issue is happening right now. Is this because it is up in my attic and it is cold? I don’t know but my service installer is coming tomorrow. I have already had one damper replaced.
When they set up which units heat and cool which spaces, really think about is this going to work. To give you an example, I have one bedroom that is tied to my laundry room. Since this bedroom faces south, the heat never goes on. The laundry room on the other hand is large enough that it probably should have its own duct damper. The heat never goes on in the laundry room. I am going to have to revisit this issue this winter. (Last winter we put in another duct because there was not enough air going into that room.)
I have a ten year warranty on the units but Water Furnace only reimburses for some of the labor cost and parts. In addition,you need to have the units checked twice a year like your normal heat and air conditioning system. Ask what that is going to cost in advance, so you know.
I would also suggest buying 2 sets of filters for each unit. You have to wash them sometimes. As they dry, you can install the other one.
Savings
I keep my downstairs and upstairs at 68 during the winter and during the summer my downstairs is 76-78 and upstairs is at 74-76. I have an energy star house so I had to have all the duct seams mastic (which I would encourage anyways). Anywhere you could “swipe” a credit card through two pieces of wood, I had to use silicone to close the gaps, and I had to pass their blower door test. All 3 floors have Icynene (basement through 2nd) in the exterior walls.
Geothermal savings are more in the summer than the winter but don’t believe the 70 percent figure you hear unless you live where it is warmer. I think I am more like 50-60 percent in the summer and 40-50 percent in the winter but I don’t know. It is hard to know because I only have an electric bill which includes all my lights (which is pretty efficient lighting) as well as my geothermal. I compare myself to houses that are new construction using gas. Perhaps I am doing better than I think.
I was told that my savings would be about 20-30 percent in the winter and 70 percent in the summer. These numbers may not take in account the Icynene. I know that has impact.
Also, don’t forget to check out what your state’s incentives and rebates are.
Water Furnace has a nice savings calculator for you to use to see what your savings would be if you installed a geothermal system versus a conventional heating and cooling system. Before you enter in your information, make sure you know your per kilowatt cost for electricity and cost for natural gas.
In addition to the savings, I like the fact that there are no condensers outside like you see in conventional air conditioning systems. The system is very quiet except that one wall that rumbles a little.
Heat Recovery Units Needed
In addition, if your house is vety tight you need to install an energy recovery system to circulate air in your house. I have a HEPA/heat recovery system in my attic by Broan. (These units should also be in the closet with the geothermal units.) See my article, “Is Your House Suffering from Bad Breath?”
Water Furnace also makes an energy recovery system . In addition , I have 2 humidifiers which put moisture in the airin the winter. They are made by Aprilaire and are the wrong units for the geothermal units. They were put in by the Company after the boss passed away. I have retrofitted them to work. Again, Water Furnace makes their own humidifiers to work with the system.
Since the geothermal system does not heat water as hot as boilers, they need humidifiers that can heat their own water. There are specific humidifiers that are made to be used for geothermal systems.
References
Whoever you use, make sure you get a couple of references. Try to get references from people who have had their geothermal systems for at least a year or so. You want to hear from someone who already went through both a heating and cooling season.
In addition, see if you can get a reference from someone who has the same size house that you are building. Ask them for a copy of the electric bill. It should show you their electrical cost for the whole year.
Solar option
As for solar, I looked into that too. It was too expensive for the savings that I would receive. This is totally off the top of my head, but I remember that 3 years ago, the cost of the system was about $60,000 or so and NJ gave back 60% I think. The problem was a 10k system which was only going to produce 13,500 kilowatts. At the time it was 9.8 cents per kilowatt in NJ, my savings for the year would only be $1323. The payback (15-18 years) would be horrible based on the cost of the solar panels. I am waiting for more efficient and less costly solar panels. In addition, NJ has changed its program.
Would I do it again?
You bet I would in a heart beat. I love this system despite some of the installer issues. It is quiet, efficient, saves me money, and helps the Earth. What else can I ask for?
Brian, I hope I was able to answer your questions. Please let me know what you decide. If you have any further questions, post again.
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Looks very interesting…just watched the video. Looks like it would be a pretty involved process though to install everything needed, and expensive but in the long run I’m sure its worth it, plus its environmentally friendly. I first got into Green technology when I learned of solar paneling and then some small wind turbines.
Matt-I actually feel for the money that geothermal is quickest payback for me in the northeast. I have an article about a wind turbine in the que if I can ever finish it. I would really appreciate your comments on this article when it comes out. I have mixed feelings about this particular wind product.
Readers, my service company showed up today to find that someone had stepped on a damper wire up in the attic. So my damper is fine. So the only true maintenance I have had on the system is the one damper. All of the other issues were installer issues.
Green Talk,
I have been designing and installing Geothermal Energy Systems (water-source heat pumps) in the Northeast since 1978 and the outdoor temperature should NOT be an issue. The equipment that I use (Hydron Module) is manufactured in South Dakota where it gets a LOT colder than here (i.e.- minus 40°F) and they work perfectly. Water Furnace makes a fine unit, too, and is fully capable of handling sub-zero temperatures. Most likely, your equipment is undersized for your home and/or your loop field is too small and too shallow.
Hi Gary, thanks for responding. Readers, Gary is an architect and engineer as well.
I may not have been clear what I wrote. My geo works fine when it gets very cold except that it may go to the electric back-up if it is not meeting the heating demands. When it goes to electric back-up, the cost to run it gets very expensive. It is similar to having an electric heat. It is 1 to 1 kilowatt at that point and significantly more expensive than when it normally runs.
I had an incident last winter with one of my geos where it could not meet the demand because it was programmed wrong. (Long story.) My bill increased 50% because it was running all the time for 2 weeks and probably went into electric back-up. My system is not undersized for my house, and I am extremely insulated since I am an energy star house.
You bring up a good point. How do people know if there systems are adequately sized or oversized given a closed or open celled insulation? In addition, can you tell us about the systems you install and design.
Also, can you tell us for different areas what should people expect their heating and air conditioning bills to look like per square foot if you can. What do you also think the payback on a system should be too.
Gary, thanks for commenting and look forward to your future comments. Please list your company as well and what areas of the country you install. The more information my readers have, the better. Anna
Hi Anna,
I did not mean to insult your house, quite the contrary. And I thought (for some reason) that you had a horizontal loop instead of a vertical loop. I personally believe that vertical loops in the Northeast make a lot more sense. First this is because we have a lot of rock close to the surface which makes deep trenches for horizontal loops very expensive (or impossible in NH- the Granite State). Second, vertical loops draw from energy from a deep (>100′) ground temp of approx. 55°F in this region versus 42°F for ground close to the surface (<12′) which makes for much better efficiencies.
If your backup heat comes on only if there is a problem with the water-source heat pump, then that is exactly what the backup heat is supposed to do- take over if the primary heating system is not doing the job for whatever reason.
You asked, “How do people know that their system is adequately sized..?”. For our Clients (my company is VIRSTAR Corp.- http://www.virstar.com ), we start every project with an in-depth energy analysis for the home, commonly called a “Heat Calc”. This takes into account the floor, wall, and ceiling areas that are exposed to outdoor temperatures and, using the R-value for the insulation, calculates the heat loss for each of those surfaces to arrive at a total heat loss for the home. Factors such as the U-value (inverse of R-value) for windows, door, and skylights are also factored into these calculations. There are many such heat calc programs (usually a spread sheet type of program) available on the Web. However, most of them do not take into account heat losses due to air infiltration or, more often, throw in a factor for these losses. For homes such as yours that are insulated with Icynene or Polyurethane foam, this air infiltration is reduced, for practical purposes, to Zero due to the sealant properties of the foam. As such, we utilize our own heat calc program which factors in the Type of insulation in addition to the R-value to arrive at the home’s overall heat loss. After that, it is very simple- the heating unit must be able to generate at least this maximum heat loss rate per hour or it will not be able to heat the house adequately.
For the A/C side, it gets a little trickier. If the A/C unit is oversized, then it will not run long enough to adequately remove the moisture from the air and the house will feel “clammy”. Your Water Furnace unit, with its two-stage capability, is ideally suited to address this issue. Cooling loads are much lower in the Northeast than Heating loads. So, your system can run on Stage 1 for cooling and perform quite efficiently while running long enough to eliminate humidity.
You asked, “…what heating and A/C bills look like per square foot..?” Any number that I might give on a sq.ft. basis would be meaningless to most people. Computing what heat/cool costs should be with a Geo system is a complex calculation for which you need to (a) know the total heat loss of your home, (b) know the rate per Kilowatt of electricity from your local utility, ( c) know the efficiency rating of your Geo equipment, and (d) know what the ambient temperatures per season are for your region. A more simple way that I use is that it costs $1.17 for the typical water source heat pump to generate 138,000 BTU’s given a cost of electricity of $0.186 per Kilowatt. One gallon of Oil contains 138,000 BTU’s and costs (currently here in NH) $3.01. You can use these numbers, adjusted for your local costs of electricity and oil, to derive the cost benefit of heating with Geo for your area. The typical Geo system that we design and install takes 4 to 6 years to pay for itself completely.
Green Talk, can you say more about your unit being “programed wrong”…we have just moved into a new house with Geo and we had a huge sticker shock with our first electric bill, it was twice what we expected. I believe our unit isn’t working correctly, we’ve had our installer return and he said our issue is “heat loss” due to fiberglass insulation vs. newer better types…we also have an unfinished basement (where the unit is located) and he suggested insulating that would help….any thoughts or suggestions from the group???? Please Help!!
Country Boy, my units were programmed for well instead of the closed loop that I have. My new installer told me that this is why one of my units frooze up in the winter. Actually, some of my units are in an unconditioned space in the attic. After, my installer passed away, another dealer came to look at the units and told me they should be in a conditioned space to be more efficient. We are in the process of building an insulated closet around them. However, my bills are not that high. I wonder what else is going on. My house has icynene which means it is better insulated with the fiberglass but again, something sounds wrong. Country Boy, can you give me some more facts. Take a look at your electric bill. What are you paying for electricity, how large is your house, and how many killowatts did you use last month, what is the size of your unit or units. Is the loop closed, open, or well? Does the geo sound like it is always running? Do you have emergency heat backup on yours? Do you have more than one unit? My neighbor’s units were not hooked up so during the winter he was only running with 1/2 of his units on! His bill was absurd.
Check your thermostat to see if it is emergency heat.I will see if Gary can help. Any other geothermal experts, you can always jump in. Anna
Country Boy,
I would be only too happy to try and help find out the problem, but, as Anna said, there is a lot of info regarding the system that is needed. Here is the list:
1. Manufacturer, Model No., Size (tons), and Type (water-to-water, water-to-air, combo) of Geo Unit?
2. Type of Geothermal Heat Source (Well, Horizontal Ground Loop, Open Loop, etc.)?
3. Square footage of your home that is heated?
4. Exterior wall thickness, type of insulation, and insulation thickness or R-value rating?
5. Attic insulation type and thickness or R-value rating?
6. Geographic location of your home?
7. Incoming and Outgoing Geo Loop temperatures, flow rates, pressures (any data that you have gauges for)?
8. Price you pay per Kilowatt Hour of electricity and the Demand Charge (if any) for electricity that you pay?
9. Who is your electric utility?
10. What type of back-up heat do you have (if any) and is it running?
From the answers to these questions, I will have another set of in depth questions. Don’t worry; we will get to the bottom of this issue.
Gary, you are the best! I need to start an “ask Gary column”. This post may not have Gary’s information. He installs systems in the Northeast and designs systems anywhere. His company is http://www.virstar.com. He has been in the geothermal business since 1978. Out of the goodness of his heart, he has been helping me and others with our geothermal systems. He also cleared up alot of misconceptions that I was told about my own geothermal system. As much as I wrote about my own system, Gary has taught me so much more. Anna
Gary and Anna, thanks so much for offering to help me…I’ll gather all the info you requested and post again when I have it. I really appreciate the help!!
Gary and Anna, I’ve tried to answer Gary’s questions the best I could..I had put my answers in “blue” text…but I’m not sure that will show up on the post…so I’ve repeated all of Gary’s questions – with my answers at the end of each question…thanks again…the latest is that we have an “expert” from the utility coming out in early Feb. to evaluate our house for “heat loss” and to try and help figure out our problem..thanks again.
1. I would be only too happy to try and help find out the problem, but, as Anna said, there is a lot of info regarding the system that is needed. Here is the list:
1. Manufacturer, Model No., Size (tons), and Type (water-to-water, water-to-air, combo) of Geo Unit? – Climate Master, Model # Tranquility TTV049 (4) Ton Geo- Thermal Double Flow Center
2. Type of Geothermal Heat Source (Well, Horizontal Ground Loop, Open Loop, etc.)? Vertical Ground Loop
3. Square footage of your home that is heated? – 2700 sq ft (first floor and second floor – unfinished basement is 1800 sq ft, and we have 3 vents downstairs but they are closed (we are going to finish the basement in a few years)
4. Exterior wall thickness, type of insulation, and insulation thickness or R-value rating? The basement has 10 inch walls of concrete with the back wall being above ground. In terms of insulation, per the bid from the contractor I have the following: Overhead of house has 15 ½” (R-38) fiberglass blowing insulation, overhead of dormer and bay area on 1st floor 12” (R-38) Kraft Paper, Insulate under dormer with 6” (R-19) Kraft Paper batt insulation, wall between house and garage with 3 ½” (R-13) Kraft Paper batts, insulate sidewalls of house with 3 ½” (R-13) Kraft Paper batts
5. Attic insulation type and thickness or R-value rating? – see above
6. Geographic location of your home? Northern Kentucky (near Cincinnati, Oh) FYI in Nov. we averaged high of 55 and low of 36, Dec. H of 44 L of 27, Jan (2007) was H of 39 L of 21.
7. Incoming and Outgoing Geo Loop temperatures, flow rates, pressures (any data that you have gauges for)?Not sure where to find out what the incoming/outgoing temps are, flow rates, etc…any direction on how to find this data?
8. Price you pay per Kilowatt Hour of electricity and the Demand Charge (if any) for electricity that you pay? I pay .0771986 per Kilowatt hour…however when you add in local taxes and an environmental surcharge it equals .0872384 per KW hr. For perspective our Dec avg KW/day was 127/day …our new bill for January shows that we are now using 97 kw/day…I had a phone call with the local utility company and they told us they would expect a house our size to be between 70-80 kw/day.
9. Who is your electric utility? Owen Electric (owenelectric.com)
10. What type of back-up heat do you have (if any) and is it running? The back up electric heat that came with the Geo unit , is the only back up heat we have. It has ran several times over the last several weeks- but we haven’t tracked exactly how much it’s been on.
From the answers to these questions, I will have another set of in depth questions. Don’t worry; we will get to the bottom of this issue.
Country Boy,
It looks like your installer’s comment about being under insulated is correct. The R-19 under the dormer should be doubled and your R-13 walls should be at least R-19. With fiberglas, you will have lots of air infiltration which is a huge source of heat loss. And if you have no insulation between your unheated basement and your 1st floor, that is also costing you money. This should be at least R-19. The R-38 in the attic is fine, but you should check for gaps or places where the insulation is not full depth.
I forgot to ask about your windows and doors. Who is the manufacturer and do you know the U-value for them? Basically, you need to find any location where air is coming in (walk around with a lit candle and see if the flame is being blown to the side near any exterior walls- careful not to set anything on fire!!). These drafts need to be stopped.
With respect to your Vertical Loop, what is the depth of the loops and how many are there? (I’d like to know the total loop length.)
Since you are heating 2,700 sq.ft., it seems that your 4-ton unit is undersized, especially given your insulation R-values. I would have put in at least a 5-ton unit, but you are in a much warmer climate than me, so I’d have to do an energy calc to find out what it should be. In any case, there is no way that 4-ton unit would be able to handle the additional load of heating your basement of 1,800 sq.ft.
By the way, how is it that your basement is 1,800 sq.ft. and your 1st & 2nd floor together are only 2,700 sq.ft.? Is the 2nd floor over only part of the home? Please give me a breakdown of sq.ft. for 1st and 2nd floor.
As for temperatures in and out of your loops, your system should have Pressure/Temperature gauges on the incoming and outgoing loop lines. If not, you should have some installed. We typically use Winters Tridicator Pressure/Temp gauges (you can get them from Grainger on line- http://www.grainger.com/ ), or you might use the ones that just attach to the outside of the pipe (don’t require any plumbing).
At first glance, it appears that your heat pump, due to its size, cannot keep up with the demand in your home, so it kicks into electric resistance backup to make up the difference. The cost of electric resistance heating is AT LEAST 3 TIMES as expensive as the Geo system, maybe 5 times as expensive.
To test this, you could disconnect your backup heat for a month and see what happens, both in terms of how warm your house is and in terms of the resulting electric bill. If you disconnect the backup heat and the Geo system on its own cannot bring the house up to the temperature that you’ve set on the thermostat, then you have your answer- it is too small and/or your loop is too small.
When you give me the additional information that I’ve asked for (including loop temps), I will run an energy analysis and tell you what size the unit should be.
Gary-
Remember we had this discussion about why I have electric backup? I could not understand why you were asking me about loop size since I knew that my installer installed the loop 300 plus feet in the ground. So, I asked the new company who is providing maintenance for me why I have electric back-up. He put the pieces together for me. He explained that the actually loop size has to be certain size or you will have to have back-up since the system will not be able to handle the load at given temperature times. Apparently (and we can’t confirm this because my installer passed away) some installers may put in a smaller loop to save money and put in electric back-up so in those occassion days when the temperature really dips, the electric is there to help. My new company uses the rule of thumb for 350 feet per ton in NJ area. My manufacturer (according to the company) mininum for the loop is 250 per ton. My installer may have thought it is not worth the added cost for those rare cold days.
Gary-did I understand this right? Also, what do you think the minium loop length should be in the northeast and how much does it vary through the country? What basically was the cost savings passed onto me with a shorter loop and installed electric backup?
Anna
Anna,
To undersize a loop to save money is pure stupidity! The Geo system saves money in operation and this is forever, so why would you want to limit the Geo system’s function by making the loop small? Wow!!
If you are talking about a Closed Loop with a circulator pump, then I usually size these to be 200′ of bore hole depth per ton. So, if you have a 4-ton system, your total loop depth should be 800′. We like to have the loop bore hole to be between 200′ and 300′ deep, so you would have (for 800′ total) 4 bore holes 200′ deep.
The loop lines run from the supply manifold, down to the bottom of the bore hole, make a “U-bend”, and come back up to the return manifold, each being a “home run”. So, in this case, you would have 1,600′ of pipe in the bore holes plus the distance from the house to the holes and back.
If the vertical loop is a Standing Column design, you need only 100′ per ton. So, for a 4-ton system, we would drill one well 400′ deep (plus a little extra to collect sediment at the bottom). A variable speed pump is placed inside of a “shroud” (4″ PVC pipe sleeve) and lowered into the well to at least 50′ below the static level of the well water.
The well water is pumped from the bottom of the well (the PVC shroud acts like a big drinking straw for the pump) into the house, through the heat pump, and back out where it returns to the top of the well just below the static level.
These rules are pretty much the same for the entire country, although there are other issues to consider if you are in the Southwest desert area.
Your cost savings for a shorter loop than is recommended is about $17/Foot of bore hole depth for the difference between what you actually installed and my rules above. So, if your system needed 800′ and you only installed 400′, you would save $6,800 on the initial installation cost.
In our systems, we rarely if ever put in the backup heat which also costs money to install; around $1,500 for 10Kw 3 phase. So this reduces your extra loop initial cost from $6,800 to $5,300.
For a 2,000 sq.ft. house (well insulated), the Geo system would cost approximately $7.00/Day (when it is 0°F to 5°F outside) to operate if your electricity costs $0.215/KwH. The electric resistance backup costs at least 3 times and possibly 5 times as much to operate.
If we use 4 times as much, then it is costing $21.00/day extra to operate using backup heat. Your initial install cost of $5,300 would pay for itself in 252 days of operation at 0°F to 5°F. You need to find out how many days/nights per year your area falls to this temp to determine how many years it would take for payback.
If your backup heat kicks on as soon as it hits 20°F, then there are a lot more days per year to add into this equation, but at a lower factor since the backup it only supplying part of the heat at these temps. So if we say it costs 2 times as much to operate when it is between 6°F to 20°F, then you have an extra cost of at least $7/Day.
For here in NH, this extra cost would pay for itself in 5 to 7 years. If you are in a warmer climate than NH, it might take 10 years. If your electric rates a lower than $0.215/KwH, then Divide $7.00 by $0.215/KwH and Multiply that result by your electric rate to get your base cost of operation per day.
For example, Country Boy states that he pays only $0.0872/KwH, but his home is 2,700 sq.ft. So, he would need 5 tons (instead of 4) or 20% more energy per day, but it costs him a lot less. His cost per day should be ($7.00 / $0.215) * $0.0872 * 1.20 = $3.41/Day at 0°F to 5°F and less on warmer days.
Therefore, the answer to your question, Anna, about the savings you realized with the shorter loop depends upon how you look at it. If you look at a 10 year or longer picture, you are losing money. If you look at a 1 year picture, you saved about $5,000 by installing a short loop.
Gary-We are just trying to figure out why I would have electric heat back-up if we did not need it. Unfortuneately, since we can’t ask anyone, we can either assume the loop is at the minium amount or we were sold something we did not need. We were told the electric heat would go on around 10-20 degrees but it has only gone on a couple times when there was a problem with the geo. It is SO expensive when that happens. As Country Boy knows as well. It is also expensive when the unit never shuts off too.
I suspect we were sold electric back-up when we did not need it. I asked my new company about your suggestion about putting a switch on the electric and they said they could do it.
As for savings, I was just wondering if my installer installed a shorter loop to cut corners, if in fact he did. I had no idea. He never gave us options. He just gave a price for the “perfect” system. If he said you needed “X” I would have said okay since he came highly reccommended. You are one of the first people who have really explained things to me. What I learned is get at least 2 quotes!
My point is if someone is trying to sell you a system, look at Gary’s guidelines above. Should a red flag go up if they start talking about electric heat backup, Gary? Anna
Anna,
You asked if a red flag should go up if a Geo installer starts talking about electric backup heat. As usual, I don’t have a simple answer.
Electric backup heat was very necessary with the old Air-to-Air heat pumps. Guys that sold these piece of junk (for the Northeast) systems who are now in Geo are quite likely to still think you need this backup.
Does the oil or gas heating system guy tell you that you need a backup system? No. Modern Geo systems that are well designed and installed correctly do not either.
So, the fundamental answer to your question is YES, if the installer insists on backup electric heat for a Geo system and says you need it when it goes below 20°F, RUN AWAY FROM THIS PERSON!! They don’t know what they are talking about.
Gary and Anna
I read your comments with interest. I recently installed a Geo system when my old heat pump died. Because of the failure I did not have as much time as I would have liked to do my research but I did interview four suppliers in the local area. Generally I was very disapointed with their knowledge. Anyway I choose the best of the bunch and the installation went pretty well (due mostly to the input of the one knowledgable lead guy.) and I have been very satisfied with the installed system. They did install the backup heat but thankfully with the worst part of winter over in Southern PA I can say it only ever turned on for short periods 2-3 days during the seasons so overall I would say the Unit is sized OK though reading your comnments Gary I have to say the idea of the bigger loop has some merit even further south.
Last week the installation company came and gave the system a check up six months after installation. They did the check when I was at work so I could not talk to the technician but they wrote down a few numbers on the service report, two of which were the water in and out pressures in the ground loop (Closed vertical type) which grabbed my attention. The pressure on the inlet was 28 psi and the outlet Pressure was 20 psi. Initially the large pressure drop stuck me so I looked up the manual for the Unit I have and it said the winter pressure in the loop should have been 50-75psi rande and the optimum pressure drop should have been in the 2-3 psi range. Needless to say the answe I got from the Service Department Manager has been less than satisfactory to date.
So Gary you mentioned having P & T guages on the lines which seams inherantly a good idea. I could not find the gauges you mentioned that clipped to the outside of the lines. Could you provide me with a more specific link. Further in your experiance what would you like to see the ground loop inlet pressure at? Also what is the effect in running the system at reduced pressure? Is it reduced flow through the system with less heat transfer etc?
Any insight you can share would be appreciated.
Darryl
Darryl-Let me see if Gary will answer. I am curious too. Anna
Darryl,
For a closed vertical loop Geo system, the pressure is not important. The water Temperature incoming (from the field) and the Flow Rate are what is important. The average closed loop that we install (4 ton system) will run around 20 PSI with a 12 GPM flow rate. The pressure drop you mention is not unusual.
I don’t know why your Owner’s Manual states that you should be running 50-75 PSI. That would require a hell of a pump to power that. What kind of equipment (and tonnage) do you have?
Anyway, to answer your question about the P/T Gauge, we use Winters Tridicator #401 P/T and install one on the inbound and outbound lines on the heat pump. You can get one of these here:
http://www.houseneeds.com/shop.....uypage.asp
The “clip on” gauge that I was talking about is (for example) from Stadler-Viega and is a Temp only type of gauge that has a built in clip to attach it to a copper pipe. It is not very accurate and costs more than the Winters, but you don’t have to do any plumbing.
For your closed loop system, the Flow Rate is more important. We install Blue-White Flow Meters, Model #F-410 or F-420 depending upon the flow rate of the system. You can buy one of these here:
http://www.blue-white.com/Prod.....ictube.asp
The manufacturer should specify in the Manual what flow rate the unit requires, typically different flow rates depending upon incoming temp. Your system may be a little more efficient at a higher flow rate than a lower one, but in no case should the flow rate be less than the recommended minimum rate. Higher flow rates require more pump energy, so the slight efficiency gain on the heat pump is offset somewhat by the pump losses.
A lot of heat pump installers do not put gauges or flow meters on their systems because (a) they don’t want the homeowner calling them every two seconds because the readings have changed, and (b) they want you to be dependent upon them so they can charge for service calls.
We put gauges and/or flow meters on all of our systems so that if a homeowner calls with a question, we can troubleshoot what is going on with the system by having the customer tell us what these gauges are reading. For us, the more “informed” the customer becomes, the better it is for everyone.
Thanks Gary! See, I am not the only one who has a back-up system. It seems that others are being lead into believing that they need a back-up system too. Anna
Anna,
Well, I never said you should not have a backup heat source. If you have a pump problem or a compressor problem, it will probably happen when it’s really cold out. (Murphy’s Law)
So, if you have backup resistance heating, you can wait a day or so and not have to pay premium service rates to fix your system right away.
Although we point this out to all of our customers, only 1 has ever added the backup to their system. It seems that the extra $1,500 or so to put it in is something most people don’t want to pay.
Gary-I meant that if you system is built correctly, you should not need back-up. Isn’t that what you explained to me? You make an excellent point about having one in case one of your geos are down. What would preminium service cost? Would running the backup be very expensive? Do your suggest getting service contracts for your system?
Also, what temperature would cause a possible pump or compression problem? Is there anything you can do to prevent a pump or compression problem? Thanks again for your help! Anna
Anna- Yes, if your system is designed and installed correctly, then you should not need a backup heat system. But even the best systems can have minor problems that cause the heat pump to not operate.
Events like this always seem to happen late at night on a Holiday, and if you are without heat and elected not to install a backup system, you need to get it fixed right away.
Service calls for late night/holidays can be double-time over their normal rate. So, if your service tech normally charges $90/hr., and you have them there on Christmas Eve for 3 hours, you will pay $540 at double-time rates. If the backup heat would have originally cost $1,500 you would have to have 3 such Holiday disasters for the backup heat to pay for itself. Since a well designed Geo system is very reliable (as reliable as any fossil fuel system), then the likelihood of such a scenario is very low. This is why so many people elect not to install the backup resistance heating which is at least 4 times more costly to operate than the normal Geo system.
Once again, remember that fossil fuel systems also have problems from time to time and need emergency service calls. And who ever heard of being required to have backup heat for a fossil fuel system? It is the same with Geo, but since Geo is new to most people, they feel more comfortable having a backup.
As for temperature issues, Standing Column designs that use reqular well water to get their heat can start having freezing problems in the heat exchanger coil when the water from the well comes in at below 38°F to 40°F, depending upon the heat pump. This is because the heat pump can drop the water temp to below freezing in the coil as it extracts its heat. Obviously, this would cause ice buildup on the inside of the coil and eventually block the coil’s water flow. The unit safety mechanism will “kick out” the compressor if the water flow drops too low to protect itself from damage. The ice melts, the flow starts back up, and the unit resumes operation after a reset.
On Closed Loop systems, vertical or horizontal, Glycol (food grade anti-freeze) is added to the water circulating in the loop so that the solution will not freeze until a much lower temp (typically 0° to 15°F). This is determined by the percentage of glycol in the loop done at time of installation.
Geo systems that are used to make ice (ice rink or restaurant ice maker or walk in freezer) do not require a colder source (as commonly believed). The extreme low temperatures (-10° to -30°F) are achieved solely through the configuration of the compressor’s refrigeration system.
There is no maintenance required on the loops, if that is what you are asking with respect to preventing problems. If the system is installed correctly in the first place, then there is nothing to worry about. If it was not installed correctly, then it needs to be fixed by a professional Geo person.
Hi,
I have read the thread here with interest, because I am looking into purchasing a vertical geo-thermal heating system for my house in Lexington, Massachusetts. I currently use gas and forced water to heat my home, which is quite old and drafty (over 100 years old, fair amount of glass windows/doors, some areas without insulation). I am curious as to three things:
1) Is a geo-thermal system better economically and/or environmentally than a natural gas/forced hot water system? If so, by how much?
2) Apparently much of Lexington is on ledge,and I’ve been warned that drilling into it is difficult. Gary, you state that you drill in NH, which I’m guessing is even worse than Lexington, so is this fear unwarranted?
3) Would I need to get town approvals to drill?
That’s all I can think of currently. Thanks in advance for any replies/comments!
David
David,
Geothermal Energy is much, much more “green” than any kind of fossil fuel. And the more that the Country (and World) implement renewable energy sources (i.e.- wind power, solar-photovoltaic, hydroelectric, nuclear, etc.), the more environmentally friendly it becomes due to the fact that all of these renewable energy sources generate electricity, and electricity is what powers a Geo system.
To use a fossil fuel for heating, you must burn it. This generates Carbon Dioxide which, if you’ve been noticing the global climate changes, is killing our planet. Although over 40% of the electricity generated in the USA today comes from fossil fuel fired plants, this will continue to drop as we progress. The production of natural gas also has a large carbon footprint for its production and, in its actual use by your furnace, has a HUGE carbon footprint from the exhaust gases.
In contrast, a Geo system has no carbon footprint from its production of heat since there is no combustion. It is my opinion that if everyone switched to Geo tomorrow, we could avoid the impending disaster from global warming.
As for the economics of Geo in comparison to natural gas, I would need to know what you are paying for natural gas and paying for electricity to answer this accurately. Using numbers from here in NH, it would cost you $1.17 to generate 138,000 BTUs of heat with Geo and approximately $1.42 to generate the same 138,000 BTUs with natural gas. (If it were propane, then the cost would be at least $3.36.)
Gas fired boilers are typically around 86% efficient, whereas Geo heat pumps run at least 95% efficient. Therefore, the Geo system would be 9% more efficient on operation alone, and would be 17.6% more efficient due to cost of energy differential. So, you would save approximately 22.6% in cost with Geo over natural gas. (You can’t just add the efficiency percentages from the two parts; they have to be computed overall.)
As for drilling, any good well driller in New England is equipped for and experienced with drilling in rock. I can recommend one for you if you’d like.
You do need a permit to drill a well in MA. Your well driller will obtain this permit for you. You will also have to obtain a permit from the Mass Department of Environmental Protection, UIC Division, in order to install and operate a Geo well. This is not a big deal and if your well driller and Geo system designer are experienced (as they need to be), then they will get this permit for you.
I might suggest that your best first investment would be to get your house into shape with respect to insulation. Your highest and fastest cost-rate of return is going to be from improved insulation. Ideally, you can insulate your home and install the Geo system at the same time.
Thanks Gary, I learned a lot from your response, and your comment about fully insulating my house is duly noted – I’ve contacted a consultant about an audit!
One follow-up question comes to mind: Isn’t electricity needed to run the pump in a geo-thermal installation, and thus fossil fuels are needed to generate that electricity? Does that add up to anything substantial, and is there a chance it negates the ecological gains from not using natural gas?
Thanks
David
David,
As I stated in my initial response, yes, over 40% of the electricity generated in the USA today comes from fossil fuel fired plants. So a Geo system using electricity does have a carbon footprint from these types of power plants.
However, there is also a carbon footprint caused by the production of natural gas. It may not be as large as the carbon footprint from the power plants using fossil fuel, but these plants are slowly going away as alternative power generation sources (wind, solar, etc.) come on line.
In the not too distant future, all electricity will be generated by renewable energy sources. This is a simple fact based upon reality that the fossil fuel supplies are running out (although coal will be around for at least another 100 years) and, at the same time, becoming too expensive to use.
In any case, the Carbon Dioxide generated by the power plants to make electricity is minimal in comparison to the CO2 generated by burning natural gas (or oil or propane) in homes for heating. Primarily this is due to the fact that the power plants have huge scrubbers and other air quality control systems in place (to meet Federal standards), whereas your home has nothing of the sort.
So, there is no chance that a Geo system which burns nothing can be compared ecologically to a fossil fuel heating system.
I am in georgia and planning on installing a 2 ton system where the load calc called for a 3 to 4 ton system. My installer is incredibly knowledgeable and I did get other bids. I am the one who wants to undersize it and my installer said it would work. We rarely get temperatures below 20 degrees here. I plan on using pull down window insulation on cold nights.
I think that the added environmental impact and financial cost of all that extra drilling and piping is unnecessary for some people. My attitude is save the money on installation and put the effort in to doing other things to deal with the occasional very cold or hot day. Obviously this is a strategy that may not work well up north. Down here you can pretty much get by with no heating or cooling at all like in the good old days. My house is passive solar and its sunny down here a lot. My dad’s house can get pretty warm just from the sun and it lasts most of the night. I think it may be unrealistic to imagine that everyone will have $30,000 to create a massive geothermal system. We have to look at minimalist systems and then not be lazy about dealing with those extreme days. Of course, if you have the money and live up north and don’t want to stick insulation on your windows on cold winter nights or superinsulate, or throw on the down comforter, then by all means it is very much worthwhile to install a big system.
Hello, I live in Cumberland, Maine and had a geothermal system installed about 1.5 years ago. I’ve had problems ever since and have had electric bills as high as $1200 in the coldest month. The lowest I’ve seen is $270. We’re quite frustrated and hoping someone might have some ideas to give me direction.
I have a 4000sf house and 1200sf finished basement which I have a zone but rarely heat. I have 2 – 5 ton climate master Genesis units (Model GSW060). One is a typical one with airhandler in the basement and services the first floor and basement. The other is a split system with the exchanger in the basement and the air handler in the attic (in an insulated room). The duct work is in the attic unfortunately. It has the typical insulation but I think it needs to be redone and sealed properly.
I have 2 inches of foam insulation sprayed in the 6” walls and R13 on top of that. The ceiling of the basement is insulated. I was told I have R50 in the attic, but I think it’s more like R38. I have jeld wen windows and doors which have a U value of .35 or less and a design pressure rating of DP50. I do have some drafts in the windows which may be an installation issue and I’ve put a claim into jeld wen. Someone should be coming soon to evaluate that.
I have 9 foot ceilings and lots of windows, it was estimated that I have a 10 ton heat load.
I have an open loop system with two 435 foot wells. The wells produce 30 and 40gpm. One of the wells also services domestic water. I have franklin cp75 constant pressure well pumps. The pressures on both were set at 60 psi. However, I asked the installer what pressure I need to maintain the 15gpm recommended thru each unit and he stated 20 psi. So I turned down the psi on one of the pumps that doesn’t also service domestic water to 35psi, but that didn’t seem to make much difference.
The water temperature in the 2 wells run between 43 and 48 in the winter and around 50 in the summer. Initially, the backup electrical heating was kicking in during cold days since it was taking some time for the geothermal to meet the demands of the thermostat. That was during the first winter, and since then I’ve turned the circuit breakers off to the electrical emergency heat and had the installer change out the thermostats.
The difference between the incoming and outgoing temperature from and to the wells is about 3-4 degrees, which seems low to me, but I wanted to check on that. Both units are set up to bleed 10% of the water when the well temperature drops below 47 degrees in the heating mode and above 52 degrees in the cooling mode. I don’t have pressure gauges on incoming and outgoing water, and the only flow meter is for the bleed. Both wells share one bleed line, which also seems a little strange, since they run independently and there is just one taco valve that they are both electrically wired to. The bleed line is a copper tube going into my foundation drain thru the concrete floor in the basement.
The tubing is copper and mostly 1” diameter, although stepped down in some areas.
One of the major problems has been related to water quality. We have high levels of iron and manganese. We have also been plagued with iron bacteria which has caused the taco valves to clog requiring over $2000 in replacement repairs. I have to filter my domestic water, but it’s cost prohibitive to try filtering the water for the geothermal units at the required flow rates.
I’ve hired a forensic engineer to evaluate the system and he hasn’t gotten back to me yet on his recommendations. He initially mentioned putting both units in one well and keeping the domestic on it’s own well which makes some sense. However, to keep the same well depth, the bleed would need to be considerably higher and I can’t bleed that much around my foundation. That still doesn’t solve my water quality issues.
I asked about converting to a closed loop system and he thought it would cost about $28,000 off the top of his head to make that conversion. I’m ready to scrap the whole thing, and change to propane boilers, which would be a lot less hassle. Although I would lose the air conditioning, and lose out on the large investment I made for this supposed high efficient system.
Please Help!!!!!! Thanks, Jeff
Jeff, you have an open loop? Gary, any ideas? Anna
Hallo! Great! Will come here more often
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