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Community and Q&A

Choosing a Door for an Insulated Garage

crc1 | Posted in Green Products and Materials on

Lots ‘o info from 10 years ago.   Summing it up, sounds like, surprise, air sealing is supreme and hinges on the hinges.   Or more accurately, on sealing margins between the panels and between the door and frame/floor interfaces as they hinge. Materials are important too but R values are apparently blatantly bologna so what’s the beta?  What works well?  eh?  And tolerates terrible weather to boot. Where is the modern sweet spot for the average Joe on his/her garage door purchase?

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  1. walta100 | | #1

    To my way of thinking the R value of the door is irrelevant because no one who cares about the cost would heat a garage.

    So if you are heating a garage cost does not matter.

    With that said I bought an insulated door because it seemed to be better quality door.


    1. Trevor_Lambert | | #4

      "no one who cares about the cost would heat a garage"

      Um... what?

      Sorry, does not compute. Can you draw a connecting line between the premise and the conclusion?

  2. GBA Editor
    Kiley Jacques | | #2

    This should prove helpful—lots of resources and solid explanation of considerations/materials/performance expectations: All About Garage Doors.

  3. crc1 | | #3

    Thank you both.

    The link to the garage door article is nice and it is interesting that the focus is cosmetic and insulation, similar to 10 years ago. The real question back then turned out to be, and still is, how well do they air seal, and this is completely ignored.

    Insulation ratings for garage doors have been unreliable in the past and there was no effort to certify them, unlike the window industry. R values in the insulated part of a door have very little to do with the overall door performance after air infiltration and thermal bridging between the insulated components.

    I would go so far as to suggest that the "All About Garage Doors" article is not all about them at all. It fails to address real world air sealing, is status quo, does not significantly address performance any more than 10-20 years ago, and that such information would be useful if anyone has guidance on this.

    Walta appears to have done what most do in the absence of useful data, he took a half hearted swing at the issue and called it good enough. I don't blame him but garage doors have room for a sizeable contribution to overall results.

    Let's see what we can find.

    1. Trevor_Lambert | | #5

      Honestly, I think Walta's comment was simply a not-so-subtle way of expressing his disgust at the idea that someone heats a garage.

  4. walta100 | | #6

    The way I see machines have no feeling heating the place you store a machine is obscene luxury in a home.

    If it is a professional shop the door will be opening often enough that heat loss thru the door will be chump change.


  5. Expert Member
    BILL WICHERS | | #7

    It can be nice to be able to heat your garage if you work on your cars or use your garage as a shop on occassion. I wouldn't want to heat a regular garage full time, at least not to comfy temperatures. Heating a regular garage to a low temperature, 40-50 degrees or so, can help the things in the garage to last longer though (things like cars), so there may be some advantage to doing that.

    I do agree that overhead doors are typically very leaky regardless of which one you buy.


  6. gusfhb | | #8

    I think it is wildly unproductive to criticize some ones decision making WRT heating a space or not.

    The OP is trying to find the most energy efficient solution to a problem, and should be assisted, not have his motives questioned

    Choose a door that has smooth vertical edges, so that the lip seals can seal. The commercial door I have at work is made like dental moulding, I mean, how is that supposed to work?

    AN insulated decent quality door is all you can hope for

    Installation of the seals is the biggest factor. The rails are junk, the wheels are junk, but if you set them up so that they cannot get away from the frame, thus they do not rattle in the wind, you are halfway there. It is my opinion that garage doors should close against a real frame like a regular door, and that although a sectional door has more opportunities for leakage than a regular swinging door, it should be possible to make it work acceptably

    The cheap plastic seal carriers don't seal to the building, so what good are they? I made my own of cedar, they seem to work decently

  7. BirchwoodBill | | #9

    In Zone 6a, some of us do care about heating the garage. The thermostat is set to 50F, so the average deltaT in the winter is about 57F. I installed rigid foam over the rafters which helped quite a bit. The garage door is the original Redwood panels from 1986. So I agree with Walta, just buy a well constructed, I.e. durable door. You can adjust the steel glides and install stiffeners to reduce the air leaks. For insulation, I just have 2x6 Kraft face insulation. I changed out the Thermostat to reduce cycling of the furnace, minor improvement but it saved money. Last time I checked, it was $30 per month for December through March with Natural Gas.

    Next house, the garage will just have hydronic heat in the floors, so i can use a solar powered heat pump, no gas, no furnace, just a heat pump with 78F water.

  8. walta100 | | #10

    Bill it seems to me we agree it would be a nice luxury to heat the garage on a rare occasion and crazy to do it often.

    Most of what I read says cars kept in heated garages are wet longer and rust more but that is an un provable argument that we are unlikely to settle.

    CRC face it if you are heating a garage you have decided you have money to burn and you are determined to burn it. Does it really matter if it 15% more or less seems unlikely to change your mind. Face it the cheap un insulated doors were never a real on your list. Money is no object, go ahead and buy the most expensive door generally you get what you pay for it will seal better and have a better R value.


    1. Expert Member
      BILL WICHERS | | #12

      Actually, I try not to judge the original poster's reasons for whatever it is they are trying to do, I just try to give them honest info to help them to achieve their goal. I think the biggest issue with most of the green movement is when people try to dictate to others, do this or don't do that. Better to let people do what they want to do, but to try to help them to do it as efficiently as possible. That's my view anyway.

      Regarding things staying wetter if the storage area is warmer, that's not actually true and is easy enough to prove. While I've never measured this with cars, I have worked with it a lot with generators and large electrical switchgear. Large electrical switchgear is typically REQUIRED to have a small heater inside. This is to keep the innards a little warmer than outdoors, which minimizes condensation on the interior of the equipment. Generators are typically heated continually with electric block heaters, which helps the engines to start in cold weather, but it also helps to keep moisture from accumulating inside the engine or in the lubricants. Just like in a wooden structure, warmer usually means dryer.

      For the OP: regarding the door itself, the biggest leaks are likely to be the sides (I'm assuming the usual roll up style door here). The sliding seals tend to be the leakiest, similar to how double hung windows tend to be the leakiest of window styles. In my expierience, the brush-type "gaskets" tend to hold up best in the sliding areas. Between the door panels you proabably want thin rubber or foam seals, with rubber probably holding up a bit better over time.


      1. walta100 | | #15

        Bill this link to thread has 30 posts on the subject and is far from definitive. But the theory I like go like this you take the warm car out of the garage when it is below freezing it quickly cools off and becomes covered in ice and snow when you park in the heated garage the ice and snow become liquid water wetting the steel for hours if the garage was unheated the ice and snow would remain in solid form keeping the steel drier. Totally unprovable one way or the other.


  9. crc1 | | #11

    Thanks all.

    1. Walta, my apologies. I don't heat my garage but will work in it and will insulate it so it will be warm by virtue of me being in it. I have plenty of long underwear that I wear under my jeans, wait for it, in the wintertime. In the summer I wear shorts. I am not the guy who runs his car 20 minutes in the morning before work. If you must know I pretty much bike to work 12 months a year. Once last year the snow was too deep and I had to turn back. Once. I don't bike to be holier than thou, I bike because I like it better than driving. Again, flannels under my pants are the best $10 ever spent when it comes to colder weather. 2 pair if it's real cold is not unreasonable for anyone who knows what real cold is.

    2. My garage will be insulated. This will make it warmer in the winter and cooler in the summer. The slab will help with both. Seems like a reasonable goal. The garage door will be by far my biggest liability to that end. Obviously it will not work if it is open but I generally keep it closed unless I am actively going in, going out or sweeping. It may be open momentarily but after that it is up to my enclosure to dictate how well it recovers.

    3. Just buy a "well built" garage door. Please define. Please identify. Which ones have better airsealing? Which ones have insulation that might actually work? Folks need help from those with experience. This is not my day job so I could use your expertise if you have any on this topic. Searching GBA mostly comes up with info from a decade or more ago.

    1. walta100 | | #16

      CRC I apologize I made some assumptions it is kind if a sore spot for me as the wife insisted we build a garage much like the one you are now describing, unheated with insulated wall, ceiling and doors.

      What I found is the garage is warmer than I would have expected both winter and summer. In the winter it is rarely below freezing. In the summer I am shocked when I go in the garage at 10 PM and it feels like an oven. Yes it is warm in the garage at than outdoors in the morning and it gets warmer all day long. Parking a hot car in the garage seems likely to bring thousands of BTUs into the garage each time. I suppose if I opened the doors all night and closed them in the morning the garage might be cooler.

      When I look at my insulated garage door I see an inch of foam 5 of the 6 sides are wrapped in steel with an R value of 0. With all that steel connecting the outdoors to the indoors I do not see much R value.

      What the market had to offer me 4 years ago seems unlikely to be the same now. Go look at the sample doors and there prices and pick the one that seem like the best value to you. The low costs doors are made from very thin steel the larger the gage number the thinner the steel is. I think I picked the 24 gage door with a foam core and a vinyl interior panel.


  10. gusfhb | | #13

    CRC it is difficult to be specific, because of money

    I could not find a pair of garage doors that were quality, insulated and looked like I wanted, so I insulated the wood ones I had

    I cannot detect serious leakage with an infrared thermometer, and I can heat the garage.

    What is your budget?

    1. Expert Member
      BILL WICHERS | | #14

      It is easier to find air leaks with a smoke stick than an IR thermometer.


  11. PLIERS | | #17

    I also liked the idea of heating a garage when needed. If you are using it to work in winter, exercise, or hang out there are times you would heat it. I don’t see the benefit in keeping it heated at all times unless you had water pipes or it was attached to the house.

    The real question is and I have asked this before what is the benefit of paying extra for an insulated garage door? Most of the extra cost could go into insulating everything else because at end of day a garage door is just a gigantic window that needs good sealing. This article from a few years back says you probably don’t need insulated doors.

    I don’t know what the actual cost benefit would be of a garage that is heated intermittently with an insulated door compared to a high quality and sealed door.

  12. andy_ | | #18

    Whether you heat the garage or not, having a decent performing garage door (and insulated garage) is still going to be beneficial because it will lower the delta T of the garage space to the attached living space.

  13. crc1 | | #19

    Yes, well, in response to those offering their insights:

    This garage is similar to what Walta is describing. Double stud, 8" thick, blown in insulation with insulated ceiling. It's an upfront investment that will give long time benefits.

    That being said the weak link is clearly the sixth wall, that operable overhead 16' x 8' door and it's ability to both insulate and air seal. As Andy S points out, this will benefit the temperature differential of the shared walls which will also be insulated and air sealed.

    By the way, I usually leave my car on the driveway to cool before putting it in the garage and, if covered in snow/ice it will likely stay on the driveway for a day or two until the sun breaks through and does the heavy cleaning work for me leaving the majority of the water content and debris outside for later cleanup.

    So, I honestly doubt that I will ever actively heat it with anything but body heat. It's possible that I might use a space heater although historically I have never done so and find it easy to bundle up while I work. As noted, the garage will likely actually stay above freezing, which is more than enough for most activities I might do, and insulating/sealing it will add even more comfort.

    (I also do not/ will not heat my driveway. I prefer my driveways near flat and south or west facing, it has served me well. I rarely even shovel anything more than a simple foot path to the street. Where I am the snow will settle significantly after a day or two, and, to be honest, I've been around long enough to know and remember that it just doesn't stick the way it used to 30-40 years ago so I let it lie. Modern cars/tires do fine 99% of the time and the other times selective shovel work is enough. )

    Although part of the issue is the door itself, and I'm all ears on that, the other part is how to achieve a good air seal. This site has spent a lot of time describing air sealing for all manners of walls, ceilings, floors, doors, windows, utilities, and fart fans but there is dang near nothing for the biggest hole in the whole house. Maybe it's not the most important but does represent a component of over all performance certainly and I'm in the midst of this build so it presents an opportunity.

    As I previously said, much of the information on this topic is a full decade old. How can that be?

    1. Expert Member
      BILL WICHERS | | #20

      >"As I previously said, much of the information on this topic is a full decade old. How can that be?"

      I don't think there have been any technological breakthroughs on overhead garage doors. Decade old info is still "current" here. Any operale door of this type is going to be fairly air leaky, since it has a lot of joints, and sliding seals which tend to be less reliable than pressure seals.

      I think you'll just have to accept that the overhead door is going to be a weak spot in your otherwise pretty well insulated garage. You may want to consider putting in a heater (I would recommend a gas unit heater -- a vented one -- here), and running it if/when needed. You can always just leave the heater turned off most of the time.


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