Sunwood Builders

The Amherst Building Department does not require a permit for a like-for-like window sash replacement in the same rough opening. Any change to opening size — enlarging an opening, adding egress to a finished basement bedroom in a student rental, or converting a window to a door — requires a building permit. Rental-property work additionally needs to satisfy Amherst's rental-unit certification requirements when egress windows and entry-door hardware are involved. Pre-1978 homes (much of the older Amherst stock) fall under federal RRP lead-paint rules — expect a $50–$150 per opening lead-safe surcharge.

Amherst window pricing sits at the Pioneer Valley mid-tier, somewhat below Boston-metro averages. Expect roughly $500–$1,000 per opening installed for a quality vinyl double-hung, $1,200–$2,800 per opening for wood or composite (Andersen 400, Marvin Elevate, Pella), and $1,800–$4,500 for an entry door with sidelights and a quality lockset. Rental-grade vinyl replacements on student-housing triple-deckers often run at the low end of that range or slightly below. Patio sliders typically run $2,500–$5,000 installed.

Massachusetts requires a written contract and a Home Improvement Contractor registration for most residential window & door installation work; ask for the registration number and check it before paying a deposit.

More on permits, costs, rebates and common questions, plus every other window & door installation contractor serving the town, on the Windows & Doors in Amherst page.