All Forum Posts by: Mark Lieb

 What type siding do you have? My first thought is to frame in the smaller unit, then use spray foam insulation to seal it up efficiently. After it is installed securely and sealed up, I would just use trim on both the interior and exterior to cover up the gap that was framed and insulated!

If you had vinyl/steel siding you may be able to match that and use actual siding to cover it up on the exterior as well. However, depending on the age of the siding it will be hard to color match. Using trim would be fine IMO!