Hi Peggy,
It can vary widely based on what kind of window you have now (aluminum, wood, vinyl, etcl) as well as if you have brickmould casing on the exterior etc. It can be up to 5" different. Just ... read more
Generally, you would call an electrician to replace the exhaust fans. In our area, there are a few service companies that provide electrical services as well as HVAC and plumbing. That way if issues ... read more