Call Us
01452 300912
Find An

Are your windows losing heat… and boosting your bills?

Most people who live in a heritage property with original timber windows have the same tale to tell. Winter means draughts, heat loss and a season filled with chills, rather than cosy evenings in. Chills that mean higher heating bills eating into household budgets.

At The Residence Collection, our approach is always backed by science. Our beautiful windows and doors are precision engineered to mitigate heat loss, and to turn those chilly nights back into cosy ones. So we’ve tasked heat experts to come up with the data that proves just how impactful heat loss through windows can be, and why you should consider choosing windows that retain warmth.

The Science

The primary way heat loss can be measured is by using u-values, which calculates the rate at which heat is lost – the lower the better. But a bunch of numbers are a little difficult to translate when it comes to the external profile of your house, with everything from windows and doors to walls providing a risk of heat loss.

So we’ve used typical u-values to illustrate heat maps that give a striking insight into what’s going on. u-values are shown across the house in a differentiating colour, from blue for the coldest zones, to red for the hottest areas. Then we can compare houses with different options for glazing, including single, double and triple options. And here are the results…

The Big Number

It turns out, when all the measurements are taken, and the heat maps are calculated, there’s a big number to consider…

On average, British houses are losing a whopping 18% of their heat through windows!

And with that comes some pretty hefty implications for bills and savings. That means windows account for nearly one fifth of our heating bills. But how do different glazing options compare when it comes to heat loss?

How your windows measure up

Single glazed windows

Unsurprisingly, single glazed windows are guaranteed to lose the most heat. Single glazed homes offer an average u-value of 5.5, which is 52.8 W/°C per window. Most of that heat comes from windows, doors and the roof, and it’s so high because the single pane of glass – as commonly found in traditional sash windows installed in heritage properties – allows heat to escape quickly, as well as inviting condensation and damp.

Double glazed windows

Double glazed windows fare slightly better, with the average home offering a u-value of 1.2, and an average loss per window of 11.52 W/°C – one fifth of the loss of a single glazed window. That’s definitely a higher level of protection, with a corresponding benefit to bills of £135 a year from savings.

Triple glazed windows

But there’s an even more efficient and cost effective option to consider – triple glazing. A triple glazed home could offer an average u-value of 0.74, and just 7.1 W/°C per window! It’s a 35% reduction in heat loss compared to double glazing, which is the key to preventing heat loss and reducing those bills even further.

Top tips for boosting insulation

When you’re considering a major renovation, it makes sense to opt for double or triple glazed windows to lock in those low u-values and keep energy bills to a minimum. But what can you do if changing your windows isn’t on the agenda right now?

First up, weather strips and film can offer a quick and easy way to fill draughty gaps. These come in several forms, including compression and V-type strips, alongside films that can coat a window and provide some reduction at least.

Thick, insulated curtains could offer further benefits, especially when made with three or four layers of material. When hung correctly, they offer an extra thermal barrier in front of windows and doors. A little more cosy, at least!

Finally, draught excluders can offer a cheap and cheerful cold weather fix, fighting floor-level draughts and filling gaps that otherwise might be missed. But make sure to accurately measure your door or window to ensure any excluder you buy fills the space.

Top quality windows are the answer

Ultimately, thermal efficiency comes from installing better windows – like those supplied by The Residence Collection. Our industry leading ranges provide both double and triple glazed options with A++ energy ratings, combined with aesthetic stylings that mean you don’t have to sacrifice on the heritage look and feel of something like a draughty sash window to feel the benefits come winter.

If your house is feeling the chill, then perhaps The Residence Collection could boost your u-value for you? 

Our carefully curated collections, include:

R9, authentically replicating 19th Century timber designs with traditionally elegant, flush exteriors and stylish, decorative interiors.

R7, with a sophisticated seven chamber design that’s flush inside and out, offering the best in modern living.

R2, providing an architectural highlight, with clean lines matched by cutting edge design and superb performance.

Our experts have also created a range of more than 25 colours from timeless classics like Grained White to modern favourites such as Eclectic Grey. Plus, dual finish is available that allows you to find windows that look as good from the inside as they do from the outside.

Data References:

  1. Data from
  2. Data from Global Windows
  3. Data from Statista
  4. Data from Money Sprout
  5. Data from Super Prof

Image Methodology

These images have been based on a thermal scale of W/°C, where 0 W/°C represents blue and 55 W/°C represents red. The calculations are detailed in full in the graph below, and are based on the transmission per degree Celsius (the loss of heat/warm air) via all the windows in a home.



At Residence Collection, we have a range of colours available and can offer everything from timeless classics like Grained White to modern favourites such as Eclectic Grey. Don’t forget, we also offer a dual finish that allows you to find windows and doors that look as good from the inside as they do outside.