Upgrade the glass. Feel it every day.

An ENERGY STAR Most Efficient window in the Northern Zone hits U-factor 0.20 or better. Three panes of glass instead of two. Low-e coatings on the inside surfaces bounce radiant heat back into the room. Argon gas between the panes slows conduction. Warm-edge spacers stop the cold ring around the frame. The result: window-side rooms stop being the coldest rooms in the house, and outside noise drops noticeably the first night.

A modern ENERGY STAR exterior door is a sandwich: insulated polyurethane core, low-e glass in any lites, full-perimeter weatherstripping, and an adjustable threshold and sweep that seal against the floor. Air leakage drops to near zero at the doors you open and close every day. In hurricane states, impact-rated cores also cut homeowner's insurance premiums. Most window projects roll one or two new exterior doors into the same crew day, the same envelope, finished.