Should I insulate the garage in the home I’m having built


I am an amateur woodworker and am having a new home built. My part-time workshop will be in the garage. Where I live (central Maryland), the winters are often cold (below freezing) and occasionally much colder (+10F/-10C and below). My current home has no insulation in the garage walls or attic, so I use an electric space heater, which is almost useless when it's really cold. I am considering having the garage in the new home insulated, since it will be much easier to do before the drywall is up.

The builder is using R-20 for the exterior walls of the living spaces, but I don't need it to be insulated enough so that I can live there, I just don't want my fingers to freeze off! I am still planning on using the space heater. The entire house will have Tyvek housewrap, including the garage (whether I choose to insulate it or not).

My question is: what level of insulation should I request? The builder wants to know what level of insulation I want before they give me a quote on the price (and I can determine if it's worth it). Do I also need to have the garage door and attic insulated to see any benefit, or can I just get by with the walls? (The walls are the critical part, since I can easily add insulation to the attic and door after the fact).

A secondary question would be: is it worth it at all? One possible answer is to do nothing and just wait for warmer weather — it's a hobby, not a profession.

UPDATE: I've asked the builder for the pricing for R-15 in the walls (can't do R-20, since the garage is framed with 2x4s, not 2x6s) and blown insulation in the attic. Still waiting to hear back from them.

UPDATE 2: The builder has quoted me over US$1400 to insulate it. Yeah, that's only $100/year, but I think I'll just wear an extra sweater, because it's not worth that much to me.

Best Answer

I would insulate it unless the cost is exorbitant.

As you have discovered, it is basically impossible to heat an uninsulated structure with just a little space heater.

Also if you are going to be keeping cars in the garage as well, having an insulated garage will keep it warmer even if you don't heat it. My garage is insulated but unheated and it is usually a good 10 or 20 ºF warmer than outside temps in the winter. The difference between a car that is 20 ºF and one that is 40 ºF in the morning is considerable.

Mine also stays very cool in the summer, so I think the insulation will help you there, not hurt you. (I bet insulating the roof/attic probably makes the biggest difference there.)