How Much Can You Really Save with New Double Glazing?

Upgrading your home with new double-glazed windows isn't just about modernising appearances or increasing security—it’s also one of the most effective ways to save on your energy bills. As households across the UK face rising energy costs, making smart, long-term investments in energy efficiency has never been more important.
So, how much can double glazing really save you? Let’s explore the numbers and the benefits.
Heat Loss Through Windows: The Hidden Cost
Older windows—especially single-glazed ones—are a major source of heat loss. According to the Energy Saving Trust, as much as 20% of a home’s heat can escape through inefficient windows. This means your heating system works harder, for longer, just to maintain a comfortable temperature.
Modern double glazing combats this by using two panes of glass separated by an insulating layer of air or gas, significantly improving thermal efficiency.
Energy Bill Savings: What to Expect
The actual savings depend on your property type and the quality of your existing windows. However, if you’re upgrading from single glazing to A-rated double glazing, here’s what you might expect:
Detached house: up to £235 per year
Semi-detached: around £150 per year
Mid-terrace: up to £110 per year
Flat or bungalow: approximately £95 per year
Over 10 years, this translates to anywhere from £950 to £2,350, and even more as energy prices continue to rise.
Other Ways Double Glazing Pays Off
The benefits of new double glazing go well beyond just lower heating bills:
Improved Comfort: Rooms stay warmer in winter and cooler in summer.
Reduced Condensation: Helps prevent mould and dampness caused by moisture build-up.
Noise Insulation: Especially valuable for properties near busy roads or urban areas.
Better Security: Modern locking systems provide peace of mind.
Higher Property Value: Energy-efficient upgrades are a strong selling point.
What Affects the Savings?Several factors can influence how much you save with new windows:
Frame material: uPVC is the most common, offering a good balance of insulation and affordability. Timber and aluminium frames are also efficient but differ in cost and appearance.
Glass type: Low-emissivity (Low-E) coatings and inert gas fillings (like argon) enhance insulation.
Installation quality: Poor installation can result in drafts and negate the benefits of good glazing. Always use certified professionals.
Making the Switch
When choosing a supplier, look for a company that provides certified A-rated windows, offers a variety of styles (like casement, sash, or tilt & turn), and is experienced in both modern and traditional homes. Local installers like Martindale Windows in Northampton, for example, offer a wide range of window styles and ensure expert installation—but many trusted providers across the UK can deliver similar quality.
The Bottom Line
If your current windows are more than 15–20 years old or are still single glazed, you're likely losing a significant amount of heat—and money. Investing in high-quality double glazing could lead to hundreds of pounds in annual energy savings, while also making your home more comfortable, secure, and appealing.
In the long run, double glazing isn’t just a home improvement—it’s a money-saving upgrade that pays for itself.