Buying guide

Replacing windows in a UK home: what to check

See if it can be repaired first

A misted double-glazed unit usually means the seal has failed, and the sealed unit can often be replaced without changing the frame. Worn hinges, handles and locks can usually be swapped too, so it's worth asking for a repair quote before you replace the whole window.

Replacement windows fall under building regulations

In England, replacing a window usually has to meet the Building Regulations. You can use an installer registered with a competent person scheme, who can self-certify the work, or ask building control to sign it off. The Planning Portal explains the rules for windows and doors.

Keep the certificate

Your installer should give you a certificate or completion record for the work. Keep it safe, because a solicitor may ask for it when you sell.

Compare energy ratings

Many windows carry an energy rating label, which makes it easier to compare products from different companies. Ask for the rating of the whole window, not only the glass.

Listed home or conservation area?

Different rules can apply. Listed building consent may be needed for work to a listed home, and some conservation areas have extra restrictions. Check with your local planning authority before you order, because it can save a costly mistake.

Read the guarantee

Ask what the guarantee covers, how long it lasts, and what happens if the company stops trading. An insurance-backed guarantee can protect you in that case.

Get more than one quote

Ask each installer to quote for the same specification, in writing. It's the simplest way to compare fairly, and it gives you time to decide without pressure.

A note on this guide

This is general information, not legal or professional advice. Rules change, so please check the official sources we link to before you make a decision.