To Insulate or Not to Insulate

[mrramsey]

I am dealing with a perplexing question. My garage is not as black and white as I make it sound so here it goes.

I have a roughly 21x21x10 attached garage. I am adding a HD45 heater. There is living space above 1/2 of it but the ceiling is all R-19. I can add additional over the other half if needed.

Two interior walls are insulated. The two exterior walls are not. Here is the problem. One wall has two large windows. 36 SF of glass. The second wall has a 16x7 door and a 3' door with 7 sf of glass.

I will be adding 1" foam to the OHD but how much am I really gaining by tearing down the drywall to insulate? The expense is not the issue just a hassle doing it.

 

[Radix2]

the missing piece is how often and to what extent you plan on heating it.

100% of the time to 70 degrees like your house - worth it.

only when you are out there - nope.

I have a similar set up - my garage stays a bit above freezing all winter (no heater at all), melting the cars, etc. - Is it the same for you ? I am not sure if that outside wall is insulated or not - considering how cheap builders are... I am guessing not.

 

[Jess]

I have an attached double garage at my home. It was built in 1990 to the current code and when I moved in 16 yrs ago, was fully finished but had no insulation in the exterior walls. My home is heated with base board electric heat. Not the best, but not the worst either. In order to keep the garage at a reasonable enough temperature to do anything out there in the middle of winter, which is mild compared to where some of you live, I decided to add 2 layers of batts to the attic and eventually do the walls. The batts in the ceiling made enough of a difference, that a small heater would warm up the space so I could spend the day in there and so far, I have not done the walls. My point being that if you do anything, do the ceiling as most heat rises. Best bet is air sealing to keep whatever heat you have in the space, then insulation, ceiling first, followed by walls. Insulated doors make a big difference too.

 

[mrramsey]

the missing piece is how often and to what extent you plan on heating it.

100% of the time to 70 degrees like your house - worth it.

only when you are out there - nope.

I have a similar set up - my garage stays a bit above freezing all winter (no heater at all), melting the cars, etc. - Is it the same for you ? I am not sure if that outside wall is insulated or not - considering how cheap builders are... I am guessing not.

For the most part I will kick it up to 65 when I am working out there and leave it at 40-45 when I am not. Most likely it stays above freezing unless we ger some real cold snaps for a week or two at a time (like single digits and lower)

Essentially it will cost about $300 to redo the drywall and add insulation. It's more the time and hassle of doing it.

 

[DC73]

Essentially it will cost about $300 to redo the drywall and add insulation. It's more the time and hassle of doing it.

That's not a bad cost so you should be able to have a reasonable payback period if you decide to insulate the two exterior walls.

Right now, those two exterior walls are the weak link in the thermal envelope. Within reason, the more you can do to improve the overall insulation of the entire thermal envelope and to reduce air leakage, the more comfortable the space will be and the less it will the cost to heat the space.

Personally, I would insulate the walls. Maybe check into blowing cellulose instead of removing the drywall completely. I'd also increase the insulation in the 1/2 of the ceiling above the space to R49 if possible or at least as much as you can up to that level.

If you choose to not insulate those walls, at least increase the insulation in the ceiling and caulk or spray foam all penetrations through the wall to minimize air infiltration.

DC

 

[fastjohnny]

just drill a couple 3" holes with hole saw and blow in cellulose. minimal disruption, minimal patching, minimal cost.

 

[Hartwell]

Greetings Mrramsey. My house was built in 1967, and the garage had no insulation. Our house stayed cold during the winter. I decided to insulate every square inch, walls and ceiling. On one wall I had to tear plywood down to do it. It made a big difference. Then I insulated the garage door and buttoned this thing down right. I used the highest Rvalue available and it really worked out. Our house now stays much cooler during the hot summer (don't use air conditioner because we don't need to now) and use very little heat in winter. This pays for itself in the short and longrun, and you'll notice a difference right away.

 

[NUTTSGT]

It might be a hassle but once it's done, you'll be happy you did it. Not only will it save you money over the years on your heating cost, it should also allow you to not have to turn the heater on till later in the heating season.

 

[Fortunateson]

What about insulating when you have radiant heating? Not really needed, helps a bit, insulate no matter what?

 

[Richard Cranium]

Insulate all you can, it will only make your life better each and every year.

 

[Fortunateson]

Insulate all you can, it will only make your life better each and every year.

That is what I figured s is my first time install radiant heating so I was wondering if much was needed. I understand the reflected heat off objects would be good to trap. Thanks.