If you have ever had an EPC completed, you are aware that it can significantly affect the value of your house, your mortgage options, and even your energy bill payments. Because of this, more households are searching for methods to raise their rating, and double glazing is one of the most common modifications.

Swan Windows, who provide double glazing in St Albans and surrounding areas, says, “not only can double glazing improve the energy efficiency of your home, it can also enhance your home’s appearance, security and value”.

But how much of a difference does it really make? And is it worth the investment? This guide walks you through what you need to know.

Understanding EPC ratings

Your property’s energy efficiency is rated from A (most efficient) to G (least efficient) by an Energy Performance Certificate (EPC). It examines items like windows, lighting, heating systems, and insulation.

Even if you don’t intend to sell or rent your property, it’s always worthwhile to keep an eye on it. Lower bills, a more comfortable house, and possibly a better price if you do decide to move are all benefits of having a higher EPC score.

The impact of double glazing on your EPC

Double glazing insulates your home by trapping a layer of air (or inert gas) between two panes of glass. This minimises the quantity of heat that escapes, making the indoor temperature more steady.

When it comes to your EPC rating, double glazing can usually add 2-3 points. That may seem insignificant, but if you’re hovering between a D and a C rating, it could be enough to propel you into the next band, increasing the value of your house or making it more appealing to potential buyers.

It also adds to other aspects of the EPC calculation, such as reduced heat loss and increased comfort, which indirectly boosts your score.

Other benefits beyond EPC scores

Even if you’re not chasing a higher EPC rating, double glazing comes with plenty of other perks that make it a smart long-term investment.

• Lower heating bills – Less heat escapes through the windows, so your boiler doesn’t need to work as hard.
• Better sound insulation – Ideal if you live near a busy road or in a built-up area.
• Fewer draughts – Older windows can let in cold air, even when closed.
• Increased property value – Buyers are increasingly aware of energy efficiency.

Plus, well-fitted double glazing can last 20 years or more, so it’s not something you’ll need to replace often.

Costs to consider

For a typical three-bedroom home, replacing all the windows with modern double glazing will roughly cost between £4,000 and £6,000, depending on the size, style, and materials used. It’s not a small investment, but the combination of lower energy bills and increased home value means it often pays for itself over time.

If you’re only able to upgrade a few windows at a time, it’s worth prioritising the largest or draughtiest ones first to get the most benefit.

When double glazing isn’t an option

If you live in a listed building or conservation area, there may be restrictions on what changes you can make to your windows. In these cases, secondary glazing can be a good alternative. It involves adding a second pane of glass to the inside of the existing window, improving insulation without affecting the external appearance.

Always check with your local authority before making changes to protected properties.

Government support and future funding

Upgrading windows or enhancing insulation isn’t always affordable, but federal assistance could be on the way. Labour has offered £13.2 billion in subsidies and low-interest loans over the next five years to help homeowners improve their energy efficiency, with the goal of upgrading five million properties by 2030.

This investment is nearly double what the previous government pledged, albeit down from an earlier £60 billion proposal. For landlords, the party is anticipated to maintain a £10,000 restriction on improvement expenditures.

If you’re thinking about making renovations, keep an eye out for prospective grant programs or financial assistance such as ECO4, HUG2, and more. They may make modifications such as double glazing much more affordable in the near future.

Final thoughts

So, in short, double glazing might not offer the biggest jump in EPC points but it can still help with energy-efficiency. It also ticks a lot of boxes: better insulation, improved comfort, added value, and increased soundproofing. It’s a long-term upgrade that makes sense both on paper and in everyday life.