Garage door insulation value?

[Bert McMahan]

I'm building a new shop/garage and am picking the garage doors right now (it's really more like a shop with some garage doors). There will be two single-car doors.

I'm looking at pre-insulated garage doors and am seeing R-values from 6.5 up to 18. Obviously "more is better" but is there a good way to calculate "how much better"? If I could find a way to compare heat loads that'd probably be best so I can see how much harder my A/C or heater will have to work. For reference I live in TN, so summers are 80's to 90's and very humid, and winters are around 30.

[Bruce King]

I’m assuming that the walls and ceiling will be insulated. I would get the highest R value that you are willing to pay for. R8 would be the lowest I would consider and R12 the highest I would pay for assuming the best is way more money. If your doors face west, the summer sun will be brutal. In the winter I only heat mine to a max of 64 but in the summer I like 72.

If painting your concrete don’t paint within 12 inches of your safety sensors, all the way across the beam area. If you get a Chamberlain opener it won’t detect a leg or small item in the way. They refuse to admit the problem but also have no interest in seeing my proof that the problem exists. I filed a report with the CPSC.
I think their belt drive with battery backup is the best opener out there but you just can’t paint the floor along that area.

[Jim Becker]

Personally, if I were faced with putting "garage" doors on my future shop, I'd opt for doors that were as close to the same insulation value as my walls and also pay attention to how they seal. Your climate isn't much different from here. Part of your decision around this will also be which way the doors face so you can understand the impact of prevailing winds for winter and sun exposure for summer.

[Bruce King]

The bottom seal is easy to get right but the side seals should be installed with the door closed and pushed tight enough so the door does not rattle when the wind blows.

[Andrew More]

Jim's right. It's very easy to get caught up in R values, but air leakage is the real killer. Unfortunately, I have yet to see a decent way to seal the sides of a garage door. The usual answer, those rubber strips isn't great, and in my case leak when I turn on the cyclone, probably because it's venting outside.

[Andrew Seemann]

Jim's right. It's very easy to get caught up in R values, but air leakage is the real killer. Unfortunately, I have yet to see a decent way to seal the sides of a garage door. The usual answer, those rubber strips isn't great, and in my case leak when I turn on the cyclone, probably because it's venting outside.

If you didn't get leakage from somewhere when you fired up your cyclone, you would not have anything venting outside:)

Same with heaters, wood stoves, etc. The make up air has to come from someplace.

[Jack Lilley]

I put a garage door in my new shop this summer. I purchased the R-18 and the double seal rubber strips for the outside. My shop is heated all the time at 50 and usually 60 when I'm working. There are no drafts around the door at all, I'm happy with it.

[ChrisA Edwards]

My house in Dallas the metal garage doors faced due south. The doors had no insulation.

On a normal 90+ degree day, I could take a reading of 140F off the inside of the door.

When I insulated the doors, with self mount kit insulation from Home Depot, that reading came down to about 5 degrees above the air temperature inside the garage.

With a mini split, I later installed in my garage, with AC in the summer and heat in the winter. Without the insulation, that mini spit would never have been able to cool/heat the garage space, especially in the summer with the radiant heat coming off the doors.

The direction the doors face has a huge effect on the heat they will radiate in the summer.

[Dave Seng]

I think that Jim B. hit the nail on the head. I'd insulate the garage door as close to the value of the wall insulation as I could. A garage door, or any window or door, is essentially a big hole in a wall that lets warm(or cool) air escape almost unimpeded without some kind of insulation. The closer that you can come to matching your wall R-value, the more stable the interior environment will be. In the long run, insulation is far cheaper than fuel or electricity.

[Jim Becker]

While many of us have our shops as "conditioned space", even folks who work at ambient temps for the season will benefit from insulation. Chris makes a really important point above about his garage door experience when it was south facing in a warm climate...that was quite a temp rise projecting through an uninsulated door! Folks who have outbuildings that have no insulation are at the mercy of the sun in warm times of the year and even a little insulation can greatly reduce the "oven effect" in the space, even when there is great cross ventilation. So yes...treat the doors with the same care as other walls as best as possible.

[Bert McMahan]

Thanks for the advice everyone. There will be two doors, one north facing and one south, but the south facing one doesn't get sunlight due to a boatload of trees. I'll look into the sealing types. The math says a higher R value won't save lots of money (ignoring radiant heating, of course) but the sealing and general "draftyness" worries me. If it's any help, the builder wants to use Clopay garage doors. I am only just now starting down this path so I'll look into how they seal at the sides. I've never used these before.

[Bob Riefer]

To provide a contrasting point of view...

I have a single low-end (but insulated) Clopay garage door on one side of my shop. I can't remember, but definitely not high R value (about 1 inch of foam in each panel) and the vinyl seals around the perimeter block wind gusts decently. The rest of my shop is pretty nicely insulated, but not perfect by any means - it's a 120 year old barn after all. I do condition my space with a mini-split year round and it is very comfortable in all seasons - I keep a base temp at all times to eliminate humidity concerns and then touch up the thermostat while working. Works wonderfully.

My point is...

While I would definitely rather have better insulation and sealing on the garage door, we have found that the hit on the electric bill is very minor when comparing extreme-temp months (those where my mini-split is being asked to keep more than 10 degrees delta vs. outside air) to the mild-temp months.... As in, the swing between our most expensive month and cheapest month is hard to even detect in our bill. So upgrading just hasn't been a priority because it's not impacting my enjoyment of the space nor is it impacting our wallet in a meaningful way.

Of course, method of heating/cooling is playing in my favor here as a good mini-split is very efficient.

That said, if money had been no object when I installed the door many years ago I would have put in the best door I could get. But money WAS a major consideration back then, and the performance has been fine.

[Bert McMahan]

Thanks Bob. I tried running this through a calculator and it estimated something like a $5 a year difference between R6 and R12, which makes sense with your math. Even at R16 I think the difference was still under $10 a year. Thanks for the info on the Clopay door. I'll probably try to get the one with the best seals rather than the best direct R value since I don't think it'll get any direct sun.

[Scott Winners]

Another way to look at it is to compare, relatively, the insulation of the shop door to the insulation in the walls of your shop and then look at the insulation in walls and windows of your home.

We could probably all save a few bucks if we splurged on a $80k set of windows for the house, but not enough savings to cover the payments on the windows.

I agree with all of the above air seals are very very important. All other things being equal, I would rather have moderate R value and minimal well controlled air leaks than crazy R value and moderate air leaks.

If your overhead door is in line with the other insulation on the property it won't hurt your resale value. If you splurge on the most insulating garage door money can buy it probably won't help the resale value.

[David Miller]

I'll add another option. My garage (shop) was built with one standard 9' wide opening. Instead of using an overhead door I build two hinged doors that are 6" thick. They are effectively moving walls hanging on heavy hinges. They have studs in them so I can hang things on them. I also don't have overhead tracks to contend with but I do have to leave room for the doors to swing in.

[Bill Carey]

I put 2" owens corning foamular - painted white - over my 2 garage doors, which are insulated, and cut my electric heating bill in the shop by 50%. And it's kind of permanent cuz I don't use the garage doors, but can be removed if needs be.

450002

[Jerome Stanek]

How tall is your shop going to be. You can have them order high clearance track to get the head room higher.

[Jim Becker]

Air infiltration is always the number one thing that has to be addressed...if the leaks are meaningful, the insulation isn't going to matter as much. Lower R value, but very well sealed can be a good choice. Of course, higher R value plus very well seals is also very nice, albeit with more up front cost. Don't make it entirely a math problem...comfort is the larger goal.

[Andrew More]

While I think insulation is important, there are other issues with a garage door the usually make it a compromise. Most that I've seen have metal frames, which means that you've got a very good thermal bridge from the inside to the outside, partially negating any insulation in the door. Second, that metal door also usually doesn't have an sealing between the panels, so that tends to leak as well.

Some insulation is good, but I wouldn't get excited about it. The truth is that most garage doors have a number of compromises to make sure they meet the requirements most people put on them: cheap, good looking, low maintenance. Insulating factor is very low on the priority list, or the door seals and door design would be much better.

[sean meltvedt]

Bert, while the insulation value has been discussed pretty well, another consideration for me is the construction. Typically the better insulated doors are thicker. Being thicker, places the metal skins further apart making the door a ton more rigid. Just like a torsion box.
Cheers
Sean

[Alex Zeller]

One thing you didn't ask about but is worth saying is I would go with a jack shaft with a torsion spring vs coil springs to counter balance the doors. It'll give you more headroom and if you go with a jack shaft style opener (if you are going have an opener) it's not going to pull on the center of the door when trying to open it. Everyone else has hit on the key points when it comes to insulating a door.

Of course you could always build your own doors if you have the option for a sliding door like on a barn. A sliding barn style door is easier to seal as you can have a 6" overlap when closed and smooth surfaces to seal against.

[Jim Becker]

Carriage doors are also an option. Like this...


https://www.youtube.com/watch?v=PEmhfZg8NY0&t=4s

[Bob Riefer]

Outswing exterior doors can really be wind sails (in my old constructions sales days, one customer had a normal "man door" pulled completely off the hinges by a sudden gust). Not saying it's impossible, but it's something to be very aware of (and that particular vid, he only had a latch for once the door was open... if wind hit during the opening, but before the latching, he has no chance of stopping it)

[Doug Dawson]

Outswing exterior doors can really be wind sails (in my old constructions sales days, one customer had a normal "man door" pulled completely off the hinges by a sudden gust). Not saying it's impossible, but it's something to be very aware of (and that particular vid, he only had a latch for once the door was open... if wind hit during the opening, but before the latching, he has no chance of stopping it)

If you’re actually driving cars in or out of the garage, one gust of wind can spoil your whole day. IOW. :^)

[Ryan Lee]

Matt Risinger just did a video on youtube about a different track and seal that is supposed to help with air leakage on the sides and the bottom seal was some type of rubber that compressed when closed to make a better seal than the standard garage door.

https://youtu.be/h7pEGEyVBLI

[Jim Becker]

For a slider, it would be kewel to have the type that slides out from flush with the wall when opening and then slides into the wall completely allowing for a full seal when closed. The tracks, top and bottom, would have a curve that makes that work. Basically, a movable section of wall. :)

[Dan Rude]

There are several products out there to push the door against the front weather stripping and cause the space between the panels to seal. One is https://www.greenhingesystem.com/ the other I just found out about is https://thermotraks.com/. Both do the same thing but with different methods. Now if they seal it so the mice do not get into the garage. :confused: Dan

[Scott Winners]

On a related note I remembered "whisper air." No affiliation and I didn't search for a link since I couldn't share it anyway. They are popular up here -might be a nickname- in tight homes with wood stoves. Stove running, open the whisper air to let fresh outside air in near the woodstove. Not running the stove, close the whisper air. They have a much higher R value than a window when closed. Two sizes IIRC, depending how big your wood stove is.

Might be a handy option if you have a tightly sealed garage door and want to run a dust collector.

[Bob Riefer]

There are several products out there to push the door against the front weather stripping and cause the space between the panels to seal. One is https://www.greenhingesystem.com/ the other I just found out about is https://thermotraks.com/. Both do the same thing but with different methods. Now if they seal it so the mice do not get into the garage. :confused: Dan


I've heard positive reviews around the green hinge system but haven't tried it myself.

As for mice... Here's how I have eradicated in my barn...

Step 1: Use the garage door "easy access" (before improving the seal a ton is even better) by putting traps right next to the left and right of the opening, facing the wall. Those little buggers will just squeeze in, and then they stay along the wall as they begin their exploration. The first year I did this, I caught two per night for a couple days, and then about one per week for some time after.

Step 2: Reduce or remove "hiding places" around the building. I used to have grass coming right up to the barn. Basically field mouse heaven (field + my warm barn). Since then, I paved parking spaces on two sides, a dog pen with gravel on the third, and a basketball court on the fourth side. Once we did this work, my mouse catching dropped to about one every 6 months at most.

edit: I don't even bait my traps... if placed where they naturally walk anyways, it works just fine.


Step 3: Some disapprove of the use of decon (and similar) but decide for yourself where you are on this topic and consider if some smartly placed "last dinners" make sense for your setup.



I went from mice running between my feet while working to present day where I catch maybe one per year.

(PS - if chipmunks come after you, let me know... been there too)

[Lee Schierer]

My detached garage door is not insulated, but the space isn't heated either. When the installed the door, I noted something different in how they mounted it. The vertical tracks are mounted on an angle so the door never touches the rubber weather stripping until just before the door is one panel from closed. This provides a wedging action that seals the door very tightly.

The two insulated doors on my regular attached garage are insulated. The replaced some older non-insulated doors and what a difference they made after they were installed. Even though the garage is not intenionally heated some of the duct work runs through the garage. The garage is also partially below grade so it stays warm enough to melt the snow off the cars and snow blower.

[Ronald Blue]

I would definitely go with insulated doors. I looked to see what mine are and was surprised that the R value is just over 18. Same type door on my shop building. If you use an opener it should be adjusted to compress the bottom seal when closed. This has kept mice out well for me. My shop is well insulated. I also have a 12" wide by 14' tall sliding door. It's got the pink R-10 foamular insulation lining it with a covering of luan underlayment over laying it. My shop is over 1600 square feet and at the moment I am keeping it at roughly 60 degrees with three 1500 watt heaters set at 60 degrees. It was 12 degrees this morning but comfortable in the shop. This is my temporary heat because I haven't got the floor heat operational yet. The point is though and it's already been mentioned is you won't regret insulation even if you didn't heat it. In the summer it takes days for it to become even 80 degrees in the shop when it's in the 90's outside. If it were just a shell I would feel and experience large temperature swings. Hopefully this year I will get a mini-split installed for summertime comfort.

[Myk Rian]

I had a 7'x16' C.H.I. insulated door installed 3 years ago. My Dayton electric heater costs dropped drastically.
The door faces SSE and the windows across the top tier light the shop well.