Photo courtesy of Energy Star
You know the verse, “oh, the weather outside is frightful, but the fire is so delightful?” 1 Perhaps it should be changed to “oh the weather outside is frightful, our natural gas bills are not so delightful.” With the expected increase in natural gas prices, it is time to start looking at how to winterize our homes.“ Air leakage and improperly installed insulation can waste 20 percent or more of the energy you pay to heat and cool your home. Typical homes have so many leaks, it’s like having a window open all the time, winter and summer.”2
As a veteran of having to plugs holes in a drafty house, I thought an article about winterizing your house would be appropriate for this time of year. After I wrote the fifth page and was still writing, I decided to break the article down into three different posts. This post is dedicated to winterizing your attic, and the next post will be about winterizing your living area.
The attic is getting special attention because heat rises. Guess where it rises to, along with your money? So, take off those ear muffs and tune in:
Winterizing your attic
“Climb up into your attic on a cold winter evening and leave a thermometer there for an hour or so. Then note the reading and compare it to  the outside temperature and  the temperature downstairs in your living quarters. If your attic is more than 10° F warmer than the outdoor temperature, or if it’s closer to the temperature inside than outside, you can figure something’s amiss.”3
Either you need more insulation, or you have too many air leaks from your living area into your attic.
First Tip: Replace Leaky Recessed Lighting with Air Tight Cans
Whenever I read about winterizing your home, the first item I read is add insulation. However, if you add insulation first, you will miss all the air leaks from your home into your attic.
Many houses have recessed lights in the second floor ceiling. I never could understand why my attic in one of my previous homes was so warm when it was so cold outside.
One day, I turned on the lights on the second floor and saw the light shining up in the attic. This gave me a clue as to how my heat was escaping from the second floor. You can not put insulation over your recess lighting unless they are air tight cans. Consider replacing those high hats with air tight recessed lighting known as IC rated recessed lighting.
Second Tip: Seal up Around Penetrations From Your Living Area
Walk around your attic. You may see plumbing vents, duct chaseways, wires, and ceiling light fixtures (not recessed lights). Even these small protrusions from the second floor to the attic can cause air leaks.You need to foam around all these items. In addition, caulk around holes and nails in the attic floor.
Third Tip: Air Conditioning and Heating Ducts
Photo courtesy of Energy Star
Check your air conditioning and heating ducts upstairs for adequate insulation.
“In a typical house, however, about 20 percent of the air that moves through the duct system is lost due to leaks and poorly sealed connections. The result is higher utility bills and difficulty keeping the house comfortable, no matter how the thermostat is set.”4
The US Department of Energy provides guidelines as to the amount of insulation that is needed around the ducts. If the ducts are not insulated, seal the duct joints with mastic. AMF Safecoat makes a good nontoxic product called DynoFlex for sealing the duct joints. Also, check to see that the ducts that extend into the second floor have adequate insulation around them. If not, stuff insulation down around the ducts.
After you have properly insulated the ducts, go down to the second floor. Take off the grill of the duct, and caulk around where the metal boot touches the ceiling drywall.
When I built my energy star house, I was required to seal around the boot to make sure that none of the air generated from the heating system did not escape into the walls. See Energy Star’s duct sealing Brochure. The illustration at the end of the brochure shows you common duct problems that impact your heating and air conditioning system.
Fourth Tip: Extra Insulation in Your Attic
Do you need additional insulation in your attic? The Department of Energy’s Insulation article links to the zip code program that will advise you as to the amount of insulation you need based upon certain criteria in your house. When I plugged in my house’s criteria I noticed that the cost per Kilowatt for electricity was a little low. Despite this, I was able to determine how much insulation I needed based upon what type of heating system I had.
Remember to insulate all knee walls in a finished attic as well. See the articles, “Button Up:Attic Doors and Knee walls,” and US department of Energy’s Knee Wall Insulation and Air Sealing.” (Attic hatches and access will be discussed in the next article.)
Don’t go crazy.
“Many energy analysts say the first four to six inches of attic insulation are ten times more cost-effective than the second four to six inches; in other words, for every fuel dollar you saved when you installed the first layer, you’ll save only about a dime by adding another layer.”5
It is better off to spend the money installing weather stripping and caulking up holes in your house. There are two invaluable articles by Mother Earth News, which I strongly advise you to read: “How to Insulate Your Attic and Save Money Year-round” and “How Not to Insulate Your Attic.”
Pay particular attention to the section about not covering your attic’s soffit vents and using a vapor barrier.
In addition, if you have Vermiculite insulation in your house, which is common in houses built before 1950, it may contain asbestos. Do not disturb it, and hire a licensed insulation contractor to remove the insulation.
Prior to insulating, look into using formaldehyde free insulation such as JM formaldehyde free fiberglass insulation, any insulation certified by Greenguard. Alternatively, check out a pricier but more environmental option, Bonded Logic’s Ultra Touch Cotton Insulation.
Fifth Tip: Beef Up the R Value of Your Attic Door
Replace your attic door with an insulated door rather than a regular wood door. If you do not want to change the door, add rigid insulation to the back of the door to increase its R-value. Add a sweep to the bottom of the door as well.
Since my attic door is not visible, I have a plain R-15 white insulated door with a sweep. I also put silicone between the threshold of the door and the step since there is a small gap between the two.
Sixth Tip: Insulate Your Attic Stairwell Ceiling
My attic stairwell has a ceiling over it. I added insulation to the ceiling in the attic. Don’t forget to use baffles between the insulation and the inside of the roof. You do not want to block your soffit vents or air flow from the vents. Otherwise, you could be creating a moisture situation in your attic.
Seventh Tip: Are Your Exhaust Ducts Vented to the Outside?
Make sure your exhaust ducts are vented to the outside. Sometimes, contractors forget to hook up the exhaust ducts to the roof or side walls in your attic. This happened both in my previous house and my new house. Why is this a problem? Warm air from a bathroom or laundry room is eliminated through the exhaust vents. Condensation could form when the warm air mixes with the cool air of the attic creating a moisture issue.
In addition, all exhaust flexible ducts should be insulated the same amount as flexible heating ducts from the beginning to the end of the duct. By adding insulation to the duct, you are eliminating any possibility of condensation forming.
Eighth Tip: Insulate Around Your Chimneys
Chimneys extend into your attic. Many people miss insulating around the sides.
“Pack gaps around an insulated chimney with unfaced rock wool or unfaced fiberglass insulation. Do not insulate bare, hot flue pipes. Do not use any combustible products such as cellulose or plastic foam here.”6
If you caulk around the fireplace, make sure you use a fire proof caulk.
Why should all of your hard earned money go towards your energy bills? If the idea of winterizing your attic is just not your thing or you would like to help determine what kind of remediation you need to winterize your attic, Energy Star provides a list of home energy raters by state. Check first if your local utility company provides this service for free or at a discounted fee.
1 “Let It Snow”, composers, lyricist Sammy Cahn and the composer Jule Styne, 1945.
2 “Air Sealing and Insulation That Works,” Energy Star
3“How Not to Insulate Your Attic” Mother Earth News, September/October 1985, reprinted.
4“Air Seal and Insulate with ENERGY STAR”, Energy Star
5How Not to Insulate Your Attic”, Mother Earth News, September/October 1985, reprinted.
6 “Insulation:The Facts, Part 4:Air leaks and moisture reduce insulation’s effectiveness,” TheOldHouseweb.com.