We're going to knock through from our living room into the room behind it (known as the Non-Room). This will give us an open plan dining area.
The living room, being at the back of the house, is very quiet. The Non-Room adjoins the integral garage and also has a window at the side (frosted for privacy as the next door house is pretty close). The Non-Room has a door into the garage, as well as into the hall.
The Non-Room (1) is noticeably cooler than the Living Room and (2) is noisier, with sound coming from the garage and also the window at the side.
If we knock through, I want to reduce both the sound entry and also heat loss.
The window at the side is already double glazed, but not that new. What would work best there?
I figured I could insulate the wall adjoining the garage (on the garage side) - what is the best way to achieve this? Oh, and one factor: garage has an asbestos ceiling, so I can't touch that.
Pic of layout below.
Cheers

