Roof and exterior
Window replacement cost
Nine windows fitted as inserts run about $6,689 — $8.20 a united inch — and about $9,140 done full-frame. That 37 per cent is the difference two quotes for the same house usually disagree by, and almost none of them say which one you are getting.
Written and edited by Pablo Ruiz Quintero
Last reviewed 2026-09-17 · Nothing you type leaves your browser
The windows
Windows are quoted by united inches — width plus height — not by the unit. A bathroom window and a picture window are not the same purchase and a price “per window” hides it.
Group 1
Group 2
Group 3
The new window goes inside the existing frame, which stays. Nothing is opened up, the interior trim is untouched and a fitter does several in a day — but you inherit whatever is wrong behind that frame, and you lose glass to the second frame inside the first.
Three quarters of the replacement market. Cheapest, insulates well because the frame is hollow chambers, and it cannot be repainted — the colour it arrives is the colour it stays.
What a modern replacement window is unless you ask otherwise. Two panes, a microscopically thin metal coating and argon between them.
Functional double glazing with no coating. Replacing it is a comfort and appearance decision, not an energy one.
4,500 heating degree days.
It changes what a saved BTU is worth.
Used only to pick a regional labour rate. It stays in your browser.
Installed, all in
$6,689
$743 a window · $8.20 per united inch · 9 windows
Full frame would be $2,450 more
Same windows, same house — $9,140 against $6,689. Most quotes never say which method they are for, and it is the commonest reason two prices for the same job disagree.
Window by window
Priced on united inches, then by style — a fixed pane is the cheapest glass you can buy and a casement the dearest that opens.
| Group | United in | Each | Total |
|---|---|---|---|
| 6 × BedroomsDouble hung | 96 | $518 | $3,110 |
| 1 × Living roomPicture / fixed | 120 | $486 | $486 |
| 2 × BathroomsHorizontal slider | 60 | $298 | $596 |
What it saves, honestly
U 0.49 today against U 0.3 new, over 127 ft² of glass and 4,500 heating degree days.
$44
Saved a year
on heating
152 yr
Energy payback
against $6,689
Yes
Meets ENERGY STAR
zone 4 wants U 0.3
That payback is longer than the windows are warranted for, and it is the number the industry does not put in the brochure. It does not mean do not buy them — it means buy them for draughts, for noise, for sashes that open, and for how the house looks. Those are worth real money. The heating bill is not where it comes back.
What it costs
National average. Windows, insert / retrofit installation, trim and flashing, and taking the old ones away. Permits, painting and any rot repair found on opening up are separate.
$8.20 per united inch installed. If the walls are coming off anyway, doing the siding at the same time is when full-frame replacement stops costing extra — the flashing work is happening either way.
Worth knowing
- Quoted by united inches — width plus height — because that is how the trade prices windows and because a figure “per window” means nothing across a house where a bathroom unit and a picture window differ by a factor of four. These 9 come to 816 united inches, which is $8.20 each installed.
- Insert / retrofit: The new window goes inside the existing frame, which stays. Nothing is opened up, the interior trim is untouched and a fitter does several in a day — but you inherit whatever is wrong behind that frame, and you lose glass to the second frame inside the first. The same windows the other way — full frame — would be about $9,140 against $6,689. Most quotes do not say which one they are for, and it is the single commonest reason two prices for the same house disagree.
- An insert puts a new frame inside the old one, so every window loses about 12 per cent of its glass — 15.2 ft² across this job. On a large window nobody notices. On a small bathroom or basement window it is visible, and on an egress window it can take the opening below code.
- Energy: going from double pane, clear, 1980s–90s (U 0.49) to U 0.3 over 127 ft² of glass in a mixed climate saves about $44 a year on heating. Against $6,689, that is a payback of 152 years — longer than the windows are warranted for. Windows are worth buying for comfort, draughts, noise and how they operate. The energy saving is real and it is not the reason.
On this page — 8 sections
- 01Quoted by united inches, not by the window
- 02The distinction that explains most of the gap between two quotes
- 03What new windows actually save, which is not what they are sold on
- 04Frames, glazing and what each actually buys
- 05Measuring, and the two mistakes that get repeated nine times
- 06Five ways this goes wrong
- 07How the calculator works it out
- 08The words on a window quote
Quoted by united inches, not by the window
The short version
- Insert or full-frame is the biggest variable. About 37 per cent, and almost no quote names which it is.
- Windows are priced by united inches — width plus height — because a bathroom unit and a picture window are not the same purchase.
- The energy payback is 39 to 152 years. On a 25-year product. Buy them for draughts and noise instead.
- An insert costs you glass. Around 12 per cent, and on an egress window that matters.
A quote of “$800 a window” is not a price, it is an average. A 60-united-inch bathroom window and a 120-inch picture window differ by more than a factor of two in glass and rather more than that in what they cost to make.
The trade prices by united inches — width plus height — for exactly that reason, and once you have that number a quote becomes comparable with another one.
united inches = width + height
- width, height
- of the opening, in inches, measured in three places and taking the smallest
- price
- per united inch, by frame material, then adjusted for style and glazing
Worked through — Nine windows — six bedroom units at 36 × 60, one picture window at 60 × 60 and two bathroom sliders at 24 × 36 — come to 816 united inches. Fitted as inserts in vinyl with double low-E glazing, that is about $6,689, or $8.20 a united inch. Which is $743 a window on average, and no single window in the house costs that.
MaterialsEstimator, Replacement window price survey · checked 2026-09-17
The distinction that explains most of the gap between two quotes
If two window quotes for the same house are far apart, this is usually why — and neither of them will say it in those words.
| Insert / retrofit | Full frame | |
|---|---|---|
| This house, fitted | $6,689 | $9,140 |
| What comes out | The sashes only | Everything, to the rough opening |
| The wall behind | Never seen | Inspected, reflashed, re-insulated |
| Interior trim | Untouched | Replaced |
| Glass | About 12 per cent lost | Full opening kept |
| Time per window | An hour or two | Most of a day |
| Rot you cannot see | Stays | Found and fixed |
| When it is right | Frames sound, trim you like, budget matters | Any doubt about the wall, or the siding is coming off |
Then full-frame stops costing extra — the flashing work is happening either way. Doing both at once is the best-value decision available on this page.
Is the siding coming off anyway?What new windows actually save, which is not what they are sold on
Every window advertisement is about energy. So here is the calculation, run on the same house, with the U-factor of what is there now against the U-factor of what goes in, over the glass area, across a heating season in the mixed middle of the country.
BTU saved a year = (U_old − U_new) × glass area × heating degree days × 24
- U
- how much heat passes through the whole window. Single glazing about 1.04, modern double low-E about 0.30
- glass area
- square feet of window, all of them together
- heating degree days
- how cold the year is where you are — about 4,500 in the mixed middle, 7,500 in the cold north
Worked through — 127 ft² of glass going from U 0.49 to U 0.30 in a 4,500 degree-day climate: 0.19 × 127 × 4,500 × 24 = 2.6 million BTU. At 80 per cent furnace efficiency and $1.35 a therm, that is about $44 a year — against $6,689 spent.
39 yr
Payback from single pane
the best case
152 yr
From sound double glazing
the common case
25 yr
The windows' own life
which is the point
+37%
Full frame over insert
same windows
ENERGY STAR / U.S. Department of Energy, ENERGY STAR window criteria by climate zone · checked 2026-09-17
Frames, glazing and what each actually buys
| Frame | Per united in | U-factor | Life | What it is |
|---|---|---|---|---|
| Vinyl | $5.40 | 0.3 | 20–30 | Three quarters of the replacement market. Cheapest, insulates well because the frame is hollow chambers, and it cannot be repainted — the colour it arrives is the colour it stays. |
| Fibreglass | $8.20 | 0.28 | 40–50 | Expands and contracts at nearly the same rate as the glass it holds, which is why the seals last longer than in vinyl. Paintable, stiffer, and about half again the price. |
| Wood, aluminium clad | $11.50 | 0.29 | 30–50 | Wood inside, aluminium outside. What goes into a house where the interior joinery matters, and the only one you can stain to match a room. |
| Aluminium | $6.50 | 0.45 | 30–40 | Strong, thin-framed and a thermal bridge — even with a thermal break it insulates worse than anything else here. It belongs in hot climates and modern architecture, not in a cold one. |
| Glazing | U | SHGC | What it is |
|---|---|---|---|
| Double pane, low-E, argon | 0.3 | 0.27 | What a modern replacement window is unless you ask otherwise. Two panes, a microscopically thin metal coating and argon between them. |
| Triple pane, low-E, argon | 0.2 | 0.25 | A third pane and a second gas gap. Genuinely better in a cold climate and genuinely heavy — the sash weight is what people notice, not the heat. |
| Double pane, clear (no coating) | 0.49 | 0.6 | What was fitted from the seventies to the nineties. Still sold cheap, and the coating it lacks is most of what makes a modern window work. |
Styles change the price too: a fixed pane is the cheapest per united inch and a casement the dearest that opens — double hung ×1, horizontal slider ×0.92, casement ×1.22, picture / fixed ×0.75, awning ×1.25, bay or bow ×2.6.
Measuring, and the two mistakes that get repeated nine times
- 01Measure each opening and add the twoWidth plus height is united inches. Measure the opening in three places and use the smallest — houses are not square.
- 02Decide insert or full-frame before pricing anythingIt is the biggest single variable and almost no quote names it. Full-frame is the only version that inspects the wall.
- 03Pick the frame materialVinyl for most, fibreglass where the budget stretches, clad wood where the interior matters, aluminium only in the south.
- 04Check the U-factor against your climate zoneENERGY STAR sets a maximum by zone. It matters for rebates more than for the heating bill.
- 05Count the trim and cappingAn insert needs the outside capped; full-frame needs trim inside and out. It is a real line and it goes missing from quotes.
- 06Work out what it actually savesU-factor difference times glass area times heating degree days. Do this before believing any payback claim.
Before the order goes in
- Each opening measured in three places — top, middle, bottom for width; both sides and the centre for height. Use the smallest. Houses are not square and a window ordered to the largest will not fit.
- Bedroom windows checked against the egress minimum, after the insert's glass loss rather than before.
- Which way each window opens, and whether a casement will clash with a path, a tap or a window air conditioner.
- Anything above a ground floor: how it gets there, and whether that needs scaffolding — it is a real line and it goes missing.
- Lead paint, if the house predates 1978. Disturbing it is regulated work and a compliant contractor charges for it.
- Who caps the exterior trim, and in what colour. It is what the job looks like from the street.
- Where the old windows go. Nine units is a skip, not a kerbside collection.
Five ways this goes wrong
01Comparing quotes without knowing which method each one is
Insert against full-frame is about 37 per cent on the same house. Comparing them directly makes the more thorough contractor look expensive and the other one look sharp.
Instead — Ask each quote which it is, in writing. If they cannot say plainly, that answers a different question.
02Buying on the energy label
The payback is 39 years from single glazing and 152 from sound double glazing, on a product warranted for 25. A decision made on that basis is made on a number that will not arrive.
Instead — Buy for draughts, noise, operation and looks. Then choose the efficient version of what you were buying anyway — the upgrade within a purchase is usually worth it even when the purchase is not justified by energy.
03Inserting into a frame with a leak history
Water that got past a window has been in the wall. An insert seals it in neatly and you find out in five years, by which time the sheathing has gone.
Instead — Any staining, soft trim or known leak means full-frame on that opening at minimum. It does not have to be the whole house.
04Forgetting egress on bedroom windows
An insert loses about 12 per cent of the opening, and a bedroom window that was just compliant becomes non-compliant. It is found at resale, when it is expensive.
Instead — Check the clear opening after the insert, not before, on every bedroom. Full-frame keeps the opening.
05Doing the windows a year before the siding
The flashing work that makes full-frame expensive happens again when the siding comes off — and doing it twice costs more than doing it once at the right time.
Instead — If a re-side is within a few years, do the windows with it. If it is not, forget it and carry on.
How the calculator works it out
Prices are a survey collected by united inches and by method, not averaged per window — insert and full-frame labour are gathered separately because it is the distinction that most often explains two different quotes. U-factors for single glazing, older clear double glazing and current low-E products come from the fenestration rating council, and the maximum U-factor by climate zone from ENERGY STAR. Heating degree days by zone come from the same place and feed the payback. All of it is on the sources page, dated.
Two things stated plainly. The payback covers heating only — cooling savings exist and are much smaller in most of the country, so including them would move the numbers by less than the uncertainty in the fuel price. And no figure here includes a rebate or a tax credit: those change yearly, they are local, and building them into a national calculation is how a number stops being true.
Nothing you type is sent anywhere — the whole calculation runs in your browser.
The words on a window quote
Two worth knowing before comparing anything: united inches, because it is the unit the price is actually in, and insert against full-frame, because it is the difference the quote will not name.
- United inches
- Width plus height. It is how windows are quoted, because a bathroom unit and a picture window are not the same purchase and a price per window hides it.
- Insert
- Also called a retrofit or pocket window. The new unit goes inside the existing frame, which stays. Cheaper, faster, less disruptive — and you inherit whatever is wrong behind that frame.
- Full-frame replacement
- The old frame comes out to the rough opening. The wall gets inspected, reflashed and re-insulated and the trim is replaced. Roughly twice the labour, and the only version that fixes what you cannot see.
- Rough opening
- The hole in the framing, before any window. A full-frame replacement exposes it; an insert never sees it.
- U-factor
- How much heat passes through the whole window, frame included. Lower is better. Modern double low-E is about 0.30; original single glazing is about 1.04.
- SHGC
- Solar heat gain coefficient — how much of the sun's heat comes through. Low is good in the south and actively bad in the north, where free winter heat is worth having.
- Low-E
- A metal coating a few atoms thick on the glass. It reflects heat back to the side it came from and it is most of what makes a modern window work.
- Argon fill
- Argon between the panes instead of air. It conducts less, it leaks out slowly over decades, and the difference it makes is real but small next to the coating.
- Sash
- The moving part that holds the glass. An insert replaces the whole unit including sashes; a sash-only kit replaces just these and keeps the frame and the jambs.
- Glass loss
- Putting a frame inside a frame costs glass — around 12 per cent of the opening. Invisible on a large window, obvious on a small one, and it can take an egress window below code.
- Egress
- A bedroom window big enough to climb out of in a fire. There is a minimum clear opening, and an insert that shrinks the glass can take a compliant window out of compliance.
- Capping
- Wrapping the exterior trim in bent aluminium so it never needs painting. It is standard with an insert and it is what the outside of the job actually looks like.
Common questions
- How much does window replacement cost?
- About $743 a window fitted as an insert on a typical house — nine windows for around $6,689, which is $8.20 per united inch. The same windows full-frame come to about $9,140. Cost per window is a poor way to think about it, because a bathroom unit and a picture window differ by a factor of four.
- What are united inches?
- Width plus height, in inches. A 36 × 60 in window is 96 united inches. It is how the trade quotes because it scales with the actual size of the window, and it is why a quote of 'X dollars a window' means nothing until you know which windows.
- What is the difference between insert and full-frame windows?
- An insert goes inside the existing frame, which stays. A full-frame replacement takes the old frame out down to the rough opening, so the wall can be inspected, reflashed and re-insulated, and the trim is replaced inside and out. Full-frame is about 37 per cent more on a typical house and it is the only version that fixes rot you cannot see.
- Why are two window quotes so different?
- Usually because one is an insert and the other is full-frame, and neither says so. That difference alone is a third of the price. After that it is frame material and glazing, both of which are easy to compare once you know you are comparing the same job.
- Do new windows pay for themselves?
- Almost never in energy, and this is the part the industry does not put in the brochure. Replacing single-pane glazing on a typical house saves about $171 a year against roughly $6,700 spent — a 39-year payback on a 25-year product. Replacing sound 1980s double glazing saves about $44 a year, which is 152 years. Buy windows for draughts, noise, operation and looks. Those are worth real money and they arrive immediately.
- Are triple pane windows worth it?
- In climate zone 6 and colder, often yes — the extra pane takes the U-factor from about 0.30 to 0.20 and the difference compounds through a long heating season. Below that the extra cost is about 35 per cent of the window for a saving that takes decades. The sash weight is what most people notice first either way.
- Which window frame material is best?
- Vinyl for most houses: cheapest, insulates well because the frame is hollow chambers, and it lasts 20–30 years. Fibreglass expands at nearly the same rate as glass so the seals last longer, at about half again the price. Clad wood where the interior joinery matters. Aluminium only in hot climates — it conducts, and even with a thermal break it insulates worse than anything else.
- How long do replacement windows last?
- Vinyl 20 to 30 years, fibreglass 40 to 50, clad wood 30 to 50. What fails first is almost always the seal between the panes rather than the frame — and a fogged window still works as a window, it just looks wrong.
- Do I lose glass with insert windows?
- Yes, around 12 per cent, because you are putting a frame inside a frame. On a large window nobody notices. On a small bathroom or basement window it is visible, and on a bedroom egress window it can take the clear opening below code — which is worth checking before ordering rather than after.
- What is a good U-factor for windows?
- It depends on where you are. ENERGY STAR wants 0.27 or lower in the northern zones, 0.3 in the mixed middle and 0.4 in the south. Meeting it matters for rebates and resale paperwork more than it matters for your heating bill, which the payback numbers make clear.
- Should I replace all the windows at once?
- Financially, doing them together is cheaper per window — one mobilisation, one crew, one set of scaffolding. But there is no structural reason to, and doing the worst elevation first is a legitimate way to spread it. What you should not do is replace half in vinyl and half in something else, because they will never match.
- When does full-frame replacement stop costing extra?
- When the siding is coming off anyway. The flashing and wall work that makes full-frame expensive is happening regardless at that point, so the incremental cost collapses. If a re-side is on the horizon, doing the windows at the same time is the single best-value decision on this page.
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About the author
Pablo Ruiz Quintero — Editor
Editor of MaterialsEstimator. Decides which documents count as a source, what every default value is, and where the line sits between what the reader parses and what the engines compute.
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