Do-It-Yourself Attic Insulation


With winter on the way and energy costs still much higher than last year, a lot of people are insulating their attics now.  This is a great step, if done correctly.  If you’re doing it yourself, it’s important to use the right details not just to save energy but also to stay safe!

Do NOT just roll out batts of insulation in the attic.  You’ll get very little benefit with fiberglass batts without rigorous attention to air-sealing.  Think of wearing a lose sweater or fleece on a windy winter day.  That fleece is a good insulating layer.  But when the wind blows through it, the heat gets sucked right out.  The same thing happens in your home as wind and the “stack effect” allow heat to escape through leaks in your home and blow right through the insulation.  (The stack effect:  warm air rises, and in the winter you whole house acts like a big chimney with the warm air rising out the top—unless you stop it)  This is a reason why you’ll see stained, dirty insulation in the attic.  It has essentially been filtering all of the air escaping your house–air that you paid to heat and cool and that you’re losing to outside. 



In fact, not adding insulation without air-sealing can lead to moisture and mold problems in the attic as the warm, moist air hits cold surfaces in the attic and the water condenses out just like it does on a glass of iced tea on a summer day.  Over time, this can lead to structural failure and other issues! 


Thus, it’s important to air-seal the attic.  This can be tricky as you need to use different materials and techniques depending on the type of holes and leaks.  For example, you can’t use foam against chimneys and flue because of the fire risk.  I can’t get in to all of the variations here.  The best resource guide for homeowners that I’ve come across is ENERGY STAR’s Do-It-Yourself Guide to ENERGY STAR Home Sealing.


Attics aren’t usually fun places, but you need to spend the time finding the holes and leaks.  And be careful up there!.  You don’t want to fall through the ceiling, you need to be on the lookout the electrical wiring, you need to watch out for protruding nails and screws, and you need to use the right techniques.


After insulating and air-sealing, it is very important to make sure that your combustion equipment—furnaces, boilers, water heaters, etc.—are operating safely and venting properly.  Most homeowner don’t have the equipment or skills to do this, so I won’t describe it here.  Your fuel company, a home performance specialist, or a good heating contractor should be able to do this for you.  As I’ve mentioned previously, carbon monoxide is not something to take lightly. 


All-in-all, this job may be more than most people want to handle.  If you hire someone to do this, make sure they are willing and able to do it right, with proper air-sealing and combustion safety testing.  If the contractor you’re talking to balks or doesn’t understand, walk away and find a contractor who can deliver what you need.




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19 Responses to “Do-It-Yourself Attic Insulation”

  1. Investing in Your Home « GreenHomes America Says:

    […] attic insulation and air-sealing.  (Remember, never think about insulation without thinking about air-sealing, too.)   And let’s assume that insulation is able to help you save $400 per year off of your […]

  2. Scott Parsons Says:

    We Love to recommend more insulation in the attic when were out on one of our home energy audits. The fact is that the more insulation there is in an attic… the better it will protect the thermal envelope of the home period.

    Energy Doctors

  3. AC Doctor Says:

    Properly sealing any part of your house, especially the attic can really help with heating bills this time of year. I do agree it is probably best left in the hands of professionals, however if you want to do it yourself, your best bet is to read up and research what you are doing beforehand, as there is a lot you could potentially make worse if not careful.

  4. david Says:

    what is the best batting insulator i can buy? owens corning or john mansville?

  5. greenhomesamerica Says:

    Hi David–

    There is very little difference between fiberglass batts from owens corning, johns manville, or others. If you’re going to use batts, buy what is convenient for you.

    That’s not the way I recommend. Installing batts properly is very difficult and time consuming. To work effectively, it must be carefully fitting into cavities with no voids or gaps. Even a half inch gap can drastically reduce effectiveness–by 40% or more! Spray applied insulation works much better at filling in the nooks and crannies. We use cellulose applied at sufficient density as the sweet spot on the cost/effectiveness scale. Spray polyurethane foam is the best widely availabe (with nanogels becoming available over the next few years), but it is considerably more expensive in most applications.

    If you’re installing batts, by all means do the critical air-sealing first and be very meticulous about fitting them in tightly in building cavities and around all obstructions such as wiring, plumbing, odd-spaced framing, etc.


  6. david Says:

    what about formaldehyde free? what does that do?

    • greenhomesamerica Says:

      According to the U.S. EPA, formaldehyde is a probably human carcinogen. IARC classifies it as a known human carcinogen–and thus probably something you want to avoid much and prolonged exposure to. Previously the resins used a binders in most fiberglass contained formaldehyde. Now, most of the manufacturers have formaldehyde-free versions. From an insulating perspective, there’s no practical difference. But to be prudent, if I were going to be using a lot of fiberglass insulation in my home, I’d go the formaldehyde-free route.


  7. “Scorched Air” Furnaces—It doesn’t have to be that way « GreenHomes America Says:

    […] That’s not the big cause of dryness in your home in the winter, though.  Air leaks are.  As air leaks out of your house (see my previous post on insulating) […]

  8. Insulate to Stay Cool « GreenHomes America Says:

    […] I’ve discussed before, insulation really only works if you air-seal first.  A good contractor will carefully air seal any leaks between the attic and the area below before […]

  9. McKinsey EE Report on Comfort and IAQ « GreenHomes America Says:

    […] on comfort and health.  Energy efficiency upgrades, including proper insulation and sealing against air infiltration [emphasis added], can address a number of common residential problems, such as drafty rooms, cold […]

  10. Attic Insulation « GreenHomes America Says:

    […] I mentioned furnace tune-ups.  Well, it’s never too early to tackle an attic insulation job.   Properly air-sealing (see recessed can light and open chase examples) and insulating your […]

  11. Kelsi Nibbana Says:

    One of our next big projects in our house will be the attic insulation. Right now, we are looking at spray foam, possibly in conjunction with denim insulation. We are no where near ready though, so we have a bit to investigate more. Thanks for the information!

  12. Tips to Save Energy This Winter « GreenHomes America Says:

    […] attic is a great place to start.  Air leaks from rooms below into the attic can be one of the biggest […]

  13. Small air leaks add up to an open “window” all winter long « GreenHomes America Says:

    […] huge difference in your comfort and utility bills. And it’s very important to air-seal BEFORE you add additional insulation—insulation doesn’t work well if you allow air to air to move through […]

  14. Air leakage–even the small cracks add up « GreenHomes America Says:

    […] Seal those leaks.  Or call someone who knows how! […]

  15. Bad use of foam–please do NOT do this! « GreenHomes America Says:

    […] important lesson:  when air-sealing or insulating, make sure it gets done right, whether you do it yourself or hire someone to do it for […]

  16. Onilne Hobbies Says:

    This is a great blog for improvment techniques. Im glad I came this site. I was looking bing for sites similar to my blog. Im a big fan of all sorts of do it yourself projects, and home improvement projects. I hope you check out my website as well. cheers!

  17. Homeowner with too much time on his hands? « GreenHomes America Says:

    […] with too much time on his hands? By greenhomesamerica Matt insulated his own attic.  And he did it right by air-sealing (and more air-sealing) first—-please, please also […]

  18. auto body shop los angeles Says:

    Solid information. This is my 1st time to this blog. Greatful for sharing . I have to bookmark this blog. I was a car mechanics specialist for a long time. My repair tip of the century is: Please do not make an attempt a very difficult repair job yourself. That can cost you mo money in the end. Thank you once again.

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