What decides the figure

Why a price per window tells you very little

The unit everyone reaches for is the price of one window, and it is close to useless on its own. Two houses on the same street with the same number of openings can land a long way apart, because almost everything that matters is about the opening rather than the glass in it.

The same word covers two different jobs. An insert — sometimes called a pocket replacement — sets a new unit inside the existing frame, which stays. A full-frame replacement takes the whole thing out down to the rough opening, and the trim and exterior capping come off with it. The second is more work, and it is the one that gets specified when the frame itself has gone.

Asking which one a figure refers to is the single most useful question about any quote.

What moves the figure

How many openings. Mobilisation, measuring and set-up are spread across the order, so the cost per opening usually falls as the count rises. This is the main reason a whole-house order and a two-window order are not simply multiples of each other.

What shape the opening is. Rectangles are the cheap case. A bay or bow, an arched head, a half-round over a door, anything that is not a standard rectangle — each of those is a made-to-order unit.

How the window opens. Double-hung, slider, casement, awning, fixed picture. They differ in hardware and in what the installer has to do to fit them.

What the frame is made of, and what you are going to. Vinyl, fibreglass, wood, aluminum-clad wood, and composite frames sit at different points, and the spread between the least and most expensive frame material is wider than the spread between glass packages.

What glass package. Double or triple, the coating on it, whether the cavity is gas-filled. In this climate zone the code sets a floor that the package has to clear regardless.

Where the opening is. Ground floor with a clear approach is one thing. Second floor over a deck, over a porch roof, or above a stairwell with no floor under it, is another — access is labor.

What is behind the trim. This is the one nobody can quote in advance. Rot at the sill, a header that was never right, or water damage found once the old unit is out becomes a change to the job. A contractor who says nothing about this possibility has not done many of them.

What a quote should spell out, line by line

Ask for these to be written out rather than folded into one number:

• Insert or full-frame, stated plainly.
• The interior trim — whether it comes off, whether it goes back, and whether it gets painted.
• Exterior capping or wrapping of the frame, and in what.
• Disposal of the old units.
• Who pulls a permit, in the cases where one is needed at all.
• The written warranty, split between glass, frame, hardware and labor — those are often four different terms from three different parties.

A figure that changed in 2026, and it is worth knowing

The federal tax credit that covered part of the cost of efficient windows no longer applies. The Energy Efficient Home Improvement Credit ran through to the end of 2025 and was terminated for property placed in service after 31 December 2025.

That matters because a lot of advice online still assumes it exists. Pages written in 2023 and 2024 that talk about claiming a credit against a window order are describing something that has since stopped. If a salesperson raises it, that is worth a question rather than a nod.

Utility programs in this area are a similar story: the local energy-efficiency programs here pay toward air sealing, insulation, heating and water heating — not windows.

Common questions

Is it cheaper to do them all at once? Per opening, usually yes, because the fixed part of the job is spread wider. Whether it is the right call is a separate question from whether it is cheaper per unit.

Can I replace just the glass in a fogged window? Sometimes the sealed unit alone can be swapped while the frame stays. Whether that is sensible depends on the age of the rest of the window, and on how many others are the same age.

Why do two quotes differ so much? Most often because one is an insert and the other is full-frame, or because one includes putting the trim and capping back and the other does not. Both can be honest. Put them side by side on those two lines first.