Choosing new windows

New windows are one of the bigger decisions you'll make about your home. They affect how warm it feels, how much noise gets in, how secure it is and how it looks from the street, and you'll live with them for decades. This guide covers the choices that make the most difference.

Start with what you want to fix

It helps to be clear about the problem before you look at products. Common reasons include:

• Draughts and cold rooms. Often caused by worn seals or single glazing.
• Condensation between the panes. A sign the sealed unit has failed. Sometimes only the glass needs replacing, not the whole window.
• Rotten or damaged frames. Usually means replacement.
• Noise. Glazing type and how well the window is fitted both matter.
• Security. Older locks and hinges may be easier to force.
• Appearance. Especially if your current windows don't suit the age of the house.

If only one or two windows have a problem, repair or reglazing may be enough. A good specialist will tell you if that's the case.

Frame materials

uPVC is the most common choice in the UK. It's low maintenance, keeps heat in well and is usually the most affordable. Quality varies between systems, so ask which profile the installer uses and how long it's guaranteed for.

Aluminium frames are strong, so they can be slimmer and hold larger panes of glass. Modern aluminium windows have a "thermal break" to stop heat escaping through the frame. They generally cost more than uPVC.

Timber suits older and period homes, and may be expected in conservation areas or on listed buildings. Modern engineered timber windows can last a long time, but they need repainting or treating every few years.

Composite (aluminium-clad timber, for example) aims to combine a low-maintenance outside with a timber look inside. It's usually the most expensive option.

Glazing

Almost all new windows are double glazed with low-emissivity ("low-E") glass and a gas such as argon between the panes. Triple glazing can improve insulation further, but it's heavier, costs more and the extra benefit in a typical UK home is often modest. It can be worth it on north-facing walls, for very exposed homes or where noise is a priority.

Other glazing options include acoustic glass for busy roads, toughened or laminated safety glass (required in certain places such as near doors and low down), and obscure glass for bathrooms.

See our guide to window energy ratings for what the labels mean.

Opening styles

• Casement windows hinge at the side or top. They're the most common style and the simplest.
• Flush casements sit flat in the frame for a more traditional look.
• Tilt and turn windows tip inwards for ventilation or open fully inwards, which makes upstairs windows easy to clean.
• Sash windows (vertical sliders) suit Victorian and Georgian homes. Modern versions are available in uPVC and timber.

Rules that apply to replacement windows

In England, replacement windows must meet Building Regulations. In practice:

• Energy performance. Replacement windows need to meet a minimum standard for keeping heat in. Your installer should confirm the product meets it.
• Certification. If your installer is registered with a Competent Person Scheme (such as FENSA, Certass or Assure), they can certify the work complies. You should receive a certificate after installation. Keep it, as you'll usually be asked for it when you sell.
• Escape windows. Some upstairs windows need to be large enough to escape through in a fire. A replacement shouldn't make escape harder than before.
• Ventilation. New windows can make a home more airtight. Your installer should check whether trickle vents or other ventilation are needed.
• Safety glass is required in certain positions.

Planning permission isn't usually needed to replace windows in a house with similar ones, but it often is for listed buildings, and conservation areas can have extra rules. Flats can also be different. If any of this applies, check with your council before you commit.

Security

Look for windows tested to PAS 24, a recognised security standard for windows and doors. Ask about multi-point locks, internally beaded glass (so panes can't be removed from outside) and locking handles.

Questions to ask before you agree a quote

1. Which frame system and glass will you use, and what are their energy ratings?
2. Will you survey and measure every window yourselves?
3. Does the price include removal, disposal, making good and any trickle vents?
4. Which Competent Person Scheme are you registered with, and will I receive the compliance certificate?
5. What guarantee comes with the windows and the installation, and is it insurance-backed?
6. How much deposit do you need, and when is the balance due?

You're always free to compare. Get the price, the specification and the timescale in writing before work starts.