One: full-frame or insert
An insert (pocket) replacement keeps the existing frame and fits a new window inside it. Faster, cheaper, less disruptive, and it loses a little glass area because the new frame sits inside the old one.
A full-frame replacement removes everything down to the rough opening. More work, and it is the only version that lets anyone see and fix rot in the sill or the framing, re-flash the opening properly and insulate the cavity.
Neither is wrong, and a cheap quote is frequently an insert quoted against somebody else’s full-frame. If there is any sign of water damage at a sill, an insert is covering it up rather than fixing it.
Two: frame material, named
Vinyl, fiberglass, composite, aluminium-clad wood and wood all behave differently on thermal movement, on strength in a large opening, on paintability and on price. "Vinyl" alone is not a specification — wall thickness, welded against mechanically fastened corners, and reinforcement in the meeting rail all vary within it.
Ask for the manufacturer and the specific product line. Every major brand sells a builder line and a premium line that share a logo and very little else.
Three: the glass package, with numbers
This is where the quotes diverge most and it is the easiest to verify, because the numbers are printed on a label. Ask for U-factor (heat transfer, lower is better), SHGC (solar heat gain, lower means less summer heat), the number of low-emissivity coatings, whether the space is argon-filled, and the spacer type.
For this climate, a low-E coating and argon fill are the sensible baseline. Triple glazing is available and is usually not the best next dollar in a Mid-Atlantic house — the same money spent on air-sealing the rest of the house typically does more.
A quote that will not give you a U-factor and an SHGC is a quote for an unspecified window.
Four and five: the parts nobody photographs
Exterior trim and capping. Is the existing wood trim being kept and painted, wrapped in aluminium coil, or replaced? Wrapping is common and it is done well or badly — badly means water gets behind it and rots the wood you can no longer see.
Flashing and air sealing. Sill pan or flashing tape at the opening, low-expansion foam rather than fibreglass stuffing in the gap, and a proper exterior sealant joint. This is what decides whether the window leaks air and water in five years, and it is the first thing a cheap quote drops because nobody inspects it.
Six: warranty, and who actually honours it
Two separate warranties exist on every window job. The manufacturer covers the unit — glass seal failure, hardware, sometimes prorated, sometimes transferable once. The installer covers the installation, which is what almost every real-world window complaint turns out to be: air leaks, water, operation, a unit out of square.
Get the labour warranty in writing with a company name on it and a term. Ask whether the installers are employees or subcontracted, because that decides who you can actually call in year three.
The sales tactics worth recognising
A price that drops steeply during one visit was never the price. A discount contingent on signing that day is not a discount, it is a close.
"Lifetime" used without a definition. Lifetime of what, to whom, transferable how many times, and prorated after when.
A per-window price with no specification attached, which is the same as no price.
An energy-saving claim as a dollar figure. Windows do reduce loss; a specific saving on your house depends on the whole envelope and nobody can honestly promise it from your doorstep.
How we quote it
Measured, per opening, with the six items above named in writing: full-frame or insert per opening, manufacturer and line, glass package with U-factor and SHGC, trim and capping detail, flashing and air-sealing method, and both warranties with terms.
Free walkthrough across Maryland and Northern Virginia. MHIC #111971, Virginia Class A #2705183185 — and because we also run the siding and the roof, a rotted sill found behind a window is something we can actually fix rather than hand off.
Get it looked at, free
We inspect across Maryland — Montgomery, Prince George's, Howard, Anne Arundel, Frederick, Carroll and Baltimore counties. Free inspection, photo report within 24 hours, and the report is yours to keep whether or not you hire us.