Repair, seal or replace?
Gaps around the frame, worn weatherstripping or a sticking sash can often be fixed. Replacement is more likely when frames are rotted, glass is failed or the unit no longer works.
Reading the labels
| Label | What it describes |
|---|---|
| U-factor | How well the unit keeps heat in or out. Lower is better. |
| SHGC | How much solar heat comes through. The right level depends on your climate. |
| Air leakage | How much air passes through the closed unit. |
| Visible transmittance | How much daylight gets through. |
Frame materials
- Wood: classic look, needs upkeep.
- Vinyl: low upkeep, limited color choices.
- Fiberglass: stable and durable.
- Aluminum: slim, but conducts heat unless it has a thermal break.
Installation
A well-made window can leak if flashing and sealing are done badly. Ask how the opening will be flashed, what happens if rot is found, and whether finishing trim and paint are included.
Questions worth asking
- Who measures, and who is responsible if it is wrong?
- Is lead-safe work needed for an older home?
- What does the product warranty and the installation warranty cover?
General information only. Gablevo is not a contractor, remodeler, lender, insurer, or licensed professional, and this is not professional, legal, or financial advice. Codes, prices, and practices vary by location and change; check with a licensed professional and your local building department. Updated October 30, 2026.