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Double and Triple Glazing: cost, savings and EPC impact
New windows are a large purchase, and the energy saving is usually smaller than people expect. They are often worth it for comfort, noise, condensation and security as much as for bills.
IndicativeFigures on this page are indicative ranges for a typical UK home. They are not a quote, a survey or an EPC. Your home will differ.
What it is
Old single-glazed or failed double-glazed units are replaced with sealed double-glazed (or triple-glazed) units in a new or existing frame. Look for a good frame and a low U-value on the unit.
Secondary glazing is a cheaper alternative for older or listed homes, and it can perform well.
Indicative cost, savings and EPC effect
| Typical cost | £3,500 to £8,000 |
|---|---|
| EPC points (SAP) | +1 to +5 |
| Bill saving | £30 to £150 a year |
Comfort, noise and security benefits are often bigger than the bill saving.
For comparison, the Energy Saving Trust’s average installed cost for a typical semi-detached home is £4,800 (A-rated double glazing). See Energy Saving Trust: Retrofit explained for the latest figures.
Replacing single glazing can add some EPC points. Replacing old double glazing with new gives less. The score reflects the whole house. See how EPC ratings work. Savings from several upgrades do not simply add up.
Is it right for your home?
- Single-glazed homes and windows with blown, misted or draughty units.
- Homes where the frames are rotten or badly fitting. Replacing just the glass in a sound frame can be a lower-cost option.
- Flats and homes in conservation areas or listed buildings may need consent, and leasehold flats may need the freeholder’s permission.
What affects the price
- Number and size of windows
- Frame material: uPVC, aluminium or timber
- Double or triple glazing
- Style, such as sash or bay windows
Questions to ask any installer
- Is the installer registered with FENSA or CERTASS, or will building control sign the work off?
- What is the whole-window U-value and the energy rating?
- What guarantee do I get, and is it insured in case the firm stops trading?
Always get a proper survey and written quote. We introduce you to one vetted firm to do that, and explain why only one.
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