Double & Triple Glazing — Keep More Heat In
Energy efficient windows cut heat loss, draughts and cold spots — most of all if you still have single glazing.
New windows are a big purchase, and the energy saving alone takes a long time to pay back — so they are usually worth it when windows need replacing anyway, or where single glazing makes rooms cold and draughty. Cheaper options such as secondary glazing, heavy curtains and draught-proofing existing windows can also help.
- Yearly saving, single to A-rated double (semi)
- £85
- A-rated windows for a semi-detached house
- ~£4,800
- Look for the energy rating label
- A-rated
What Is Glazing?
Double glazing has two panes of glass with a sealed gap between them; triple glazing has three. Energy efficient windows are rated on a scale using the window's overall performance, which is a better guide than the U-value alone. PVC frames tend to be cheapest and hardwood the most expensive.
How It Works
Survey and Quote
A window company measures each window and agrees frame material, glass and rating.
Manufacturing
Windows are made to measure.
Installation
Old windows are removed and new ones fitted and sealed, keeping any required ventilation such as trickle vents.
Certification
Replacement windows must meet Building Regulations. Installers registered with a competent person scheme can self-certify the work; otherwise building control must be involved.
Is It Right for My Home?
Most homes can have double or triple glazing. Listed buildings and homes in conservation areas may have restrictions on window styles and materials, so check with your council first. Homes that still have single glazing see the biggest improvement.
Key Benefits
Lower Energy Bills
Around £85 a year when replacing all single glazing in a semi-detached home with A-rated double glazing (Energy Saving Trust).
Fewer Draughts
Well-fitted modern windows reduce draughts and cold spots.
Less Condensation
A warmer inner pane means less condensation on the glass.
Quieter Rooms
Double and triple glazing reduce outside noise.
Lower Carbon Emissions
The Energy Saving Trust estimates around 290kg less CO2 a year for the semi-detached example.
Other Options
Secondary glazing, thermal curtains and draught-proofing can help where replacing windows is not possible.
Ask for a Free Glazing Quote
Typical Costs and Savings
Typical figures to help you compare, not a quote for your home. Your costs and savings depend on the property, how you heat it and how you use energy.
| Example | Typical Cost | Typical Saving a Year |
|---|---|---|
| Semi-detached house, all single glazing replaced with A-rated double glazing | ~£4,800 | ~£85 |
Energy Saving Trust figures for Great Britain. The Energy Saving Trust publishes these figures for a semi-detached house only; costs depend on the number and size of windows and the frame material. Source: Energy Saving Trust — windows and doors. Last reviewed September 2026.
Help With the Cost
Funding depends on where you live, your income and your home, and schemes change. We are not a government body — check the official scheme before relying on it.
Scotland, Wales and Northern Ireland
Home Energy Scotland funding can include glazing. Windows are not covered by the 0% VAT rate for energy-saving materials.
Read more on our grants guide →Frequently Asked Questions
Your next step
Thinking about Double & Triple Glazing?
It is free to ask and there is no obligation.