Free Eco Home Calculators

Glazing Comparison Tool

1 min read Last updated 20 May 2026
Quick answer For a typical 8-window UK home, A-rated double glazing (U=1.2) costs around £3,600 installed and saves £100-£140 a year. Triple glazing (U=0.8) costs around £5,200 and saves £140-£180 — usually only worth it for noise-sensitive locations or super-insulated homes.

The Glazing Comparison Tool puts A-rated double, triple and premium triple glazing side by side for the same window area. It shows install cost, U-value improvement, annual heat-loss savings, payback period, CO2 savings and noise reduction so you can pick the best-value option for your situation.

Glazing Comparison Tool

Compare different glazing options side by side to find the best value for your home.

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Check your latest energy bill. Ofgem cap (2026) is ~7.2p/kWh.

See 20 real-world examples

Each link below runs this calculator with real UK city and property inputs and publishes the exact computed savings, payback time, install cost and CO2 figures.

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How this calculator works

The same heat-loss formula as the Window U-Value Calculator: U-value × area × heating-degree-days × 24 × utilisation factor / 1000. We apply the BRE 0.6 utilisation factor to reflect solar gain offset and intermittent heating. Cost-per-window figures come from FENSA installer averages (£450 A-rated double, £650 triple, £850 premium triple). Savings convert kWh × user-supplied gas rate / 0.9 boiler efficiency.

Sources & references

Frequently asked questions

Is triple glazing worth the cost?

Usually no for energy alone — the £80-£200 install premium per window vs A-rated double earns back about £4-£8 per window per year. Triple becomes worth it when noise reduction matters (busy roads, flight paths) or when you're aiming for EPC A or passive-house standards.

What is a Window Energy Rating?

WER is a BFRC-administered A++ to E rating that combines thermal transmittance (U-value), solar gain factor (g-value), and air leakage. Most UK installers quote WER A or A+ as standard for new windows.

Can I keep my old frames?

Yes — replacing only the glazing units (sealed unit retro-fits) costs about 30-50% less than full window replacement. This works well for hardwood and composite frames but is rarely available for old uPVC.

Will new windows help with damp and condensation?

Often, but not always. Modern airtight windows reduce ventilation, which can move condensation from the windows to colder walls or ceilings. Trickle vents and mechanical ventilation are usually needed alongside.

Tool: Glazing Comparison Tool. Last reviewed: . Figures based on Ofgem price cap, gov.uk grant guidance, and Energy Saving Trust advice. Verify scheme eligibility with your installer before commissioning work.