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Are your old sash windows making your house uncomfortably hot? Learn how to stop solar heat gain and upgrade your windows for year-round comfort.
No obligation · Find out how to upgrade your windows.
We all love the sun, but when your house turns into a greenhouse in summer, it quickly becomes unbearable. If you live in London, your home is likely absorbing heat directly through your glass windows. This is especially true if you live in a period property with original single-glazed sash windows.
Sunlight carries immense amounts of thermal energy. When this short-wave solar radiation passes through your glass and hits the objects inside your room (like floors and furniture), it transforms into long-wave heat energy. Because standard single-pane glass provides practically zero thermal insulation, this long-wave heat cannot escape back out. The heat becomes trapped inside your home. This process is known as solar gain.
If your windows face south or west, they are taking the absolute brunt of the afternoon sun, making it nearly impossible to cool your rooms down without resorting to expensive and noisy air conditioning units.
Older Victorian, Georgian, and Edwardian houses with traditional single-pane sash windows are particularly vulnerable to temperature fluctuations. Single glazing is effectively just a 3mm or 4mm thick sheet of glass separating your living room from the elements.
Not only does this thin barrier allow solar heat to pour in during the peak of summer, but it also allows your expensive central heating to escape during the freezing winter months. Furthermore, older timber frames that haven't been maintained often suffer from gaps, leading to severe draughts.
There are several ways to reduce heat gain through your glass, ranging from quick DIY band-aids to permanent, energy-efficient property upgrades:
The simplest temporary way to stop heat is to block the sunlight entirely. Thermal curtains or blackout blinds can reflect the sun away before it heats up the room. However, this means you must sit in the dark during the brightest, most beautiful days of the year, which is far from an ideal living situation.
You can apply a reflective or tinted UV film directly to the interior of the glass. This bounces a significant portion of solar radiation back outside. While it helps reduce heat, it can darken the room year-round, often peels or bubbles over time, and can ruin the heritage aesthetic of traditional sash windows.
Blocking the sun before it even hits the glass is highly effective. Installing exterior awnings or solid timber shutters can provide great shade. The downside is the significant upfront cost, and the fact that many London Conservation Areas or listed buildings will not permit alterations to the exterior facade.
If you want to permanently stop heat coming through your windows while keeping your home bright and beautiful, the best investment is upgrading to slimline double glazing. At Golden Ratio Windows, we can remove your old, thin single-pane glass and replace it with high-performance double-glazed units—fitted directly inside your existing sash frames.
Modern double glazing contains a layer of inert gas (like Argon or Krypton) and low-emissivity (low-E) coatings. This drastically reduces solar gain in the summer by reflecting heat away, and provides unbeatable insulation in the winter, all without destroying the character of your period property.
Get a Double Glazing Quote TodayWe have helped hundreds of London homeowners upgrade their inefficient single-glazed windows.
Finsbury Park
"Saved our original Victorian windows when others said replace. Beautiful workmanship — our sash windows look brand new."
Stoke Newington
"Draughts completely gone. Warm house for the first time in years. Fair price and they clearly know period properties inside out."
Central London
"They completely replaced two windows in our Edwardian home. Friendly, communicative and done quickly — in just 2 days."
North London
"The detailing is very well done and accentuates the property nicely. The whole front of the house looks much better as a result."
Yes. Double glazing acts as a highly effective thermal barrier. The gap of air (or argon gas) between the two panes of glass dramatically reduces the amount of solar heat that can pass from the outside to the inside of your home. During summer, this means your house stays much cooler.
Yes, absolutely. We specialise in retrofitting slimline double-glazed units into original timber sash windows. This means you don't have to rip out the entire window box, saving money and preserving the historical character of your London property.
Yes! While draught-proofing is famous for keeping cold air out in winter, it also stops hot air from leaking into your home during a summer heatwave. A properly sealed window improves your home's overall thermal efficiency year-round.
Stop the heat and start saving on energy bills. We offer a free, no-obligation survey and quote for all window upgrades across London.
218 Hornsey Road, London, N7 7LL
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