How much will an extra-insulated door help me?

[kevinwilly]

Hey guys- I've got two crappy particle board single doors on my attached garage in Durham, NC.

Want to throw a lift in the garage eventually, but at least need to get a car in the center for now, so I'm putting in one 17'6" wide door and tearing out the center pillar (new header, etc- already had structural engineer come out).

So I'm looking at doors. I'm leaning toward the Clopay classic premium with an R value of 18.4...

But I can save 400-500 bucks by getting a door with an R value of 6-7.

Currently the garage gets WAY too hot in the summer to work in. But the attic and walls are not insulated (which I will be doing very soon). In the winter it doesn't get too cold... a space heater keeps it decently warm most the time.

But the summers... oh MAN they get hot. So hot that I sweat enough that I can barely hold onto tools.

Will the more expensive door make enough of a difference to be worth it? ANY door is going to be a huge improvement over the **** that is there. And the attic/wall insulation should make a world of difference.

I know I'll never recoup the money in heating savings (and I don't care)... but will I notice that a big enough difference in temperature to justify the money? If i'm more comfortable out there I spend more time there and get more done. But if it's only going to be a couple degrees, then it's not a big deal....

Thanks for any help!

 

[Voi]

Do the current doors face south and/or take a sustained direct hit from the sun?

 

[kevinwilly]

The doors face south-southwest. There's tall trees that partially shade them for the majority of the day, though.

 

[koditten]

I know from expertise how much an uninsulated door Will radiate heat. It's is a lot. If you want to save money, buy rigid foam board with foil backing and glue it to your existing door.

It works awesome. I don't know if better than an insulated door, but a lot cheaper.

 

[kevinwilly]

I know from expertise how much an uninsulated door Will radiate heat. It's is a lot. If you want to save money, buy rigid foam board with foil backing and glue it to your existing door.

It works awesome. I don't know if better than an insulated door, but a lot cheaper.

The existing doors are getting torn out. They are particle board and sag about 6-8" in the middle despite being only 7' wide.

The difference between an uninsulated door and R-6 or 7 door is 100 bucks. So I'm at least going to get an R-6 door.

I just need to know if getting the R-18.4 door for $500 more is worth the upgrade.

 

[1949 caddyman]

I just put in one of the R-18 polyurethane doors. Don't know about summer but it is a very solid door with the injected insolation vs the snap in insolation. If you can afford the $500 I would opt for the R18 door.

 

[CNGsaves]

Go with the better insulated garage door. You'll never regret it.

 

[ekraft84]

Go with the better insulated garage door. You'll never regret it.

This.

 

[38Chevy454]

Remember insulation works for both keeping cold out in winter (or more properly keeping heat in) and keeping the summer heat out. Combine the better insulated door with some ceiling and wall insulation and the result will be a nice working environment year-round. I would spend the extra money for the better door.

 

[NUTTSGT]

Go with the better insulated garage door. You'll never regret it.

I agree. I wish I would have sprang for the extra in my doors for the times I don't have a fire going.

Insulation is an investment. Every time you heat or cool it's a return on your investment.

 

[rburke65]

A wise manonce told me....No one has ever said, 'Damn....I wish would have bought the Black and White TV'. Meaning you will never regret buying the better product rather than trying to save the dollar. Buy the insulated door and it will pay you benefits for the next 30 years or more. Oh....and I do have the same door you are considering....very nice door.

 

[sublime68charger]

as what other have said what color door are you getting?

if your more concerned about heat in the summer get the door color that will reflect sunlight the best and deflect the heat from the sun.

what type of AC are you going to run?

you will either pay for the better door or you will pay every summer to run the AC more to get the temps where you want
and then in the winter you'll pay again to get the temp up to where you want.

any way you shake it you either pay for the better door now or pay for not having the better door yearly later.

just my thoughts

sublime out

 

[kbs2244]

I think more than insulation you need shade.
Your orientation to the afternoon sun makes your doors great solar collectors.
Can you put up some kind of awning?
If so, I would save the money on the door and spend it on an awning.
(BTW, paint the doors white.)

 

[sberry]

The door is a big part of a small building here, it would probably be worth it.

 

[kevinwilly]

The doors are definitely going to be white. Partially for thermal purposes, but also because it matches the color scheme that I am painting the house.

Currently the garage is not heated or cooled. I can run ducting if I need to, it would be trivial because it connects to the crawl space. In the winter a space heater keeps it in the high 40's which is ideal working weather to me. I'm comfortable in a t-shirt when I'm working in that. In the summer I basically never work out there because it's too hot and humid. I'm thinking the ceiling and wall insulation and SOME insulation on the doors will be good enough.....

I know that R-values are not a linear scale. So an R-18 is NOT 3 times the insulation of an R-6. It's maybe an 8% improvement.

You guys still think it's worth it? After doing some more searching, I've found several people that say SOME insulation is great, but extra insulation in a door is offset by the inherent small air leaks that they are bound to have no matter what....

I'm placing the order on the way home from work today (15% off sale ends tomorrow).... and also ordering my lift at the same time, I think.

 

[Farrviewsouthfarm]

One more reply, I didn't have the money on mind so I cheated out and then had to retro fit.....Yup spend it now, you will be glad you did on the first hot summer day

 

[kevinwilly]

One more reply, I didn't have the money on mind so I cheated out and then had to retro fit.....Yup spend it now, you will be glad you did on the first hot summer day

But did you buy a non-insulated door and then have to insulate it? Or did you buy a "regular" insulated door and then replace it with a more insulated door?

 

[megalo]

You definitely should not/can't (by code) connect your house's HVAC to your garage.

 

[kevinwilly]

You definitely should not/can't (by code) connect your house's HVAC to your garage.

Sure. Technically. By code. I don't disagree. But if that's so you don't **** exhaust fumes or something into an air return. If I have a shutoff installed and have no air return in the garage it's not going to pose any danger to anything.

 

[farphle]

It's against code for a reason. Even without a return you run the risk have having fumes and gasses enter the ducting and make it's way into the house. BIG mistake. Don't do it.

 

[JCByrd24]

I generally agree with insulating to the fullest extent however garage doors are an area that in general are a tricky one. Data shows that the panel insulation value is very exaggerated compared to the actual performance of the door, because they are very very leaky and the thermal bridging is bad. Therefore, looking at the door alone, you are likely not tripling the r-value of the door as the numbers suggest. That being said, there is logic that the panel itself being better is better than it being worse. Just like in your house even though windows are R-3 or something it doesn't mean you make your whole house r-3 or eliminate windows. With this in mind, if you are heating/cooling 24/7 you need to air seal the doors to the greatest extent and probably want to go with the better door. If you will heat it just on occasion and let it be whatever it is the rest of the time, you'd probably be ok with the R-7 door (again airsealed) and put the money somewhere else.

 

[kevinwilly]

I generally agree with insulating to the fullest extent however garage doors are an area that in general are a tricky one. Data shows that the panel insulation value is very exaggerated compared to the actual performance of the door, because they are very very leaky and the thermal bridging is bad. Therefore, looking at the door alone, you are likely not tripling the r-value of the door as the numbers suggest. That being said, there is logic that the panel itself being better is better than it being worse. Just like in your house even though windows are R-3 or something it doesn't mean you make your whole house r-3 or eliminate windows. With this in mind, if you are heating/cooling 24/7 you need to air seal the doors to the greatest extent and probably want to go with the better door. If you will heat it just on occasion and let it be whatever it is the rest of the time, you'd probably be ok with the R-7 door (again airsealed) and put the money somewhere else.

Yeah- not heating or cooling the garage. At all. Nor do I have plans to. I usually work with the door open most of the time... it's just when it's the middle of summer that there's a problem. I get cranky in the heat and tend to not get as much done as I would like.

I'm fairly certain insulating the garage itself is going to make a HUGE difference.

Either way I'm not going to be disappointed in this project because the end result is a lift in my garage.

 

[NUTTSGT]

You guys still think it's worth it? After doing some more searching, I've found several people that say SOME insulation is great, but extra insulation in a door is offset by the inherent small air leaks that they are bound to have no matter what....

I cut a couple of small wood wedges that I put in between the latches and rails of my garage doors to help hold the doors tight and prevent air leaks. I just pull them out when I unlatch the door to open.

 

[Nowater]

Sure. Technically. By code. I don't disagree. But if that's so you don't **** exhaust fumes or something into an air return. If I have a shutoff installed and have no air return in the garage it's not going to pose any danger to anything.

So, if one depressurizes an area like a house by sending air out (into a garage without an air return) then makeup air must come into the house from somewhere. A nice source is any combustion air chimney such as from a gas or oil burner, or even a fireplace. You don't want those fumes in your house either.


Back to the door concern, the air sealing on the door will easily make or break the benefit of the extra insulation. There is another thread about special door hinges with springs built in so that the door sits tighter against the frame to keep out air. Do the math: a 1/4" air gap around an opening perimeter of 10 feet by 10 feet by 10 feet by 10 feet (40 feet in all) equals 1/4 " times 480 lineal inches. That equates to 120 square inches, almost equal to a one square foot (144 square inches) opening allowing hot or cold air to blow in.

 

[kbs2244]

You need air circulation more than temp regulation.

Get an exhaust vent, up high, to get rid of your hot and humid air and draw in some cooler air through the door.
It may not even be need to be powered.

I have learned that low velocity, but constant, air movement will cool very well.
If you want to get into the technical side of it look into Antebellum (Pre Civil War for you Yankees) architecture and even Polynesian and Indo-China architecture.

They knew how to keep a constant, low speed, air current going for comfort.