You could reframe(or simply shim the existing studs) in the two outside walls with 2" by 6" studs(or simply add 2" by 2" shims) and use R-19 batts.

With new sheet rock, you would loose 2" on those two walls.

Simply adding R-15 batts to the garage wall would be fine.

You can blow cellulose insulation into the existing wall without having to take the drywall down to get you up to R15 assuming 2x4 construction.

In addition to that there is an interesting product we looked at a while ago that was panels of 2" rigid foam laminated on to drywall that could be added to the existing walls. This would add another R10-12.

Pointless to add insulation if the existing steel door is not insulated. If it is insulated, double check sweeps and gaskets to be sure they're tight. Caulk baseboards/trim on the exterior walls as well. An unimproved residence of that era is likely not to have much or even any insulation.

This post was edited by worthy on Tue, Oct 28, 14 at 10:36

Thank you Handymac, rwiegand and worthy

This room as the entire main level of house has been redone about 7-8 years ago but I think they never put in any extra insulation. Just cosmedic changes.Looks lovely but cold

How can I tell if steel garage door is insulated?
I will check all the caulking on trim and baseboards, but I think that is done, meaning there is baseboards all around and then a quarter round piece on the bottom touching floor.
Do you mean I should calk at the base of the quarter round or is that piece enough and takes the place of caulking.

I think we are going to have to go with insulation in the walls.

Handymac,

I have been reading articles on r19 insulation and what needs to be done.
Can you tell me if you think all this is necessary.
It is for a 1944 house , that has cinderblock construction with stucco op top of it.
The one wall we removed partially upstairs in bathroom because we were putting in new tub we could see under the drywall, and we could see the cinderblock and a very very small amount of what looked like shredded paper...
So for this ,mudroom on ground level, I read I have to put Tyvek paper up against cinderblock
then R-19 batts,then plastic film, then new drywall.

In your opinion , do I need all this.
Thank you

I'd hire a cellulose company to come out, and blow the walls through small holes.