Double glazing cost
Double glazing cost is part of the window price with us: every new window has double glazing as standard. We have no separate price per m² for glass, because we don't supply glass on its own.
Double glazing cost per m²
Because double glazing is standard in the window, we don't price it separately per m². What a window cost with us is on the price pages for uPVC and aluminium windows, measured on our own quotes, in GBP excl. VAT and import duties.
Double glazing supplied and fitted
We don't give that price: we don't install. You fit the window yourself or with an installer.
Replacing double glazing in existing frames: cost
We don't supply that. For new glass only in an existing frame, ask a glazier for a price.
Double or triple: the difference in price
Triple glazing costs more than double. The difference for your windows is in the quote if you have both priced.
Work out your double glazing price
Put your windows together in the configurator with double glazing and request a quote. Within three working days you'll have the price for your sizes, glass and colour.
What HR++ double glazing is
HR++ is the Dutch name for double glazing with a heat-reflecting coating on one of the panes and argon in the cavity. The coating lets light through but reflects heat back into the room; argon conducts heat less well than air. HR++ glass generally has a Ug between 0.9 and 1.2 W/m²K. The HR++ double glazing in our windows is 1.1.
From single or old double glazing to HR++
Single glazing has a Ug of around 5.8, and ordinary double glazing without a coating 2.7 to 3.0. With HR++ you go from five or six to just above one. If you still have single glazing or old uncoated double glazing, HR++ is the biggest step there is to make in glass.
HR++ in three versions
Clear HR++ is the standard glass. If you want light without being overlooked, there is obscure double glazing with the same Ug of 1.1. For a door or a low window there is safety glass, double: laminated glass class P4A with a Ug of 1.0, which stays held by the interlayer if it is struck. You choose the version per window in the configurator.
What Part L asks of a replacement window
In England, a replacement window in an existing home needs a U-value of 1.4 W/m²K or WER band B (Approved Document L). That figure is for the whole window, frame included, not for the glass: the Ug of 1.1 of our double glazing is not the number that is checked. The U-value of your whole window is in your quote. Replacing windows is notifiable work: your installer registers it through a competent person scheme such as FENSA or Certass, or you notify building control beforehand. Scotland and Northern Ireland have their own rules.
Why double glazing is standard with us
HR++ double glazing is in every window you put together, unless you choose something else. It insulates many times better than old glass and is lighter and thinner than triple. For a bedroom or kitchen window of average size, many people find it the sensible middle way. If you want more, switch to triple in the glass step.
A warmer pane on the inside
With single glazing the pane feels cold in winter and water often runs down the glass in the morning. HR++ keeps the inner pane closer to room temperature. You notice it as less cold by the window, fewer draughts along the windowsill and less condensation on the glass.
Double glazing in a door or next to the front door
In a door or a side panel, too, HR++ is the standard glass. If the glass is low down, or next to the lock of a front door, choose the laminated version: safety glass, double, class P4A. It insulates almost as well as clear HR++ and stays held by the interlayer if it is struck. For a bathroom window or a side panel facing the street there is obscure double glazing, which lets light in without passers-by seeing inside.
When you're better off going straight to triple
If you have large areas of glass, a house that is otherwise well insulated, or plans for a heat pump, it's worth having triple priced as well. The extra cost is in the quote. For an average window in an ordinarily insulated house, double glazing remains a good choice.
How heavy double glazing is
Double glazing weighs 20 to 24 kg per square metre. A window with one and a half square metres of glass therefore quickly weighs more than 30 kg in glass alone, before you add the frame. Allow for that when fitting.
Frequently asked questions
How much does double glazing cost per m²?
With us, double glazing is part of the window price and isn't priced separately per m². We don't supply glass on its own.
How much does double glazing cost?
Double glazing is the standard glass in every new window and is in the window price. What a window costs is on the price page for uPVC and aluminium windows.
How much does double glazing cost with fitting?
We don't work that out, because we don't supply glass on its own and don't install. For glass in an existing frame, a glazier is the place to go.
How expensive is double glazing compared with triple?
Cheaper. Have both priced in the quote to see the difference for your windows.
Is the price including VAT?
Our prices for the UK are in GBP excluding UK VAT and import duties, which are payable on delivery.
Can I buy double glazing from you on its own?
No, we only supply glass in a new window. For new glass only in an existing frame, go to a glazier.
What is the difference between HR, HR+ and HR++?
They are Dutch labels for successive steps in insulating glass; the more plus signs, the better the glass insulates. We supply HR++ double glazing as standard and triple glazing (HR+++) as an option.
Is double glazing enough for a new window?
For many homes, yes: it is a big step up from old glass. Part L sets its limit on the whole window (1.4 W/m²K for a replacement window in England), not on the glass alone; the U-value of your window is in your quote. If you want the best there is in glass, choose triple.
Know what you want? Put it together.
No form first: you watch your window take shape as you choose. The price follows in the quote, within three working days.
Configure your window or door
Where we have a guide price, it is on the page, not behind a form — not a quote and not a final price; the amount for your sizes is in the made-to-measure quote.
Request a quote