How your windows and doors could be raising your energy bills

Did you know your windows could cause around 18% heat loss to your home, and draught-proofing windows could save your energy bills about £40 a year?

When it comes to our homes we work hard to find the best energy tariffs, we consider whether we want a fixed tariff, we compare energy deals, consider switching energy providers, we look for modern heating and insulation solutions, we try to lower our carbon footprint through using electric vehicles, solar panels and air source heat pumps.

Yet, one of the easiest ways to help our homes improve their energy efficiency and carbon usage, is to think about our doors and windows!

In this article, we explore reasons why doors and windows become less energy efficient and cause heat loss, how to check if yours are inefficient, ideas you can try to reduce their energy loss, and whether it's worth replacing windows and doors.

What causes doors and windows to be less energy efficient? 

With both doors and windows, how well they work at keeping draughts out and you warm, depends on whether they stop heat escaping through them. If air's leaking from seals and gaps, and if sunlight can't pass through your window's glass, you're going to find your doors and windows aren't keeping you as warm as they should, and your home isn't energy-efficient.

Top reasons your windows and/or doors are causing energy loss 

If you think your windows and doors are no longer keeping you as warm as they once did, it's probably due to age and wear. After time, materials start to break down and lose their initial efficiency. Seals start to deteriorate, wood begins to rot, and even uPVC window frames can warp, meaning the frames don't fit the glass as snugly as they once did, leading to gaps.

Different types of energy-efficient windows 

The most energy-efficient windows tend to have two or three layers of glass, with gaps between each sheet. The glass sheets are sealed in a single-unit frame made out of materials such as wood, uPVC or aluminium.

Single glazed windows 

If you've got an older property that hasn't been updated, your windows could easily be single-glazed - in other words, they only have one layer of glass. Single-glazed windows are nowhere near as efficient at keeping you warm and cause other problems:

• Heat loss: one layer of glass is very conductive and doesn't effectively prevent heat loss
• Draughty: single glazed windows are more prone to draughts - making your home colder and more expensive to heat
• Condensation: with only a pane of glass, condensation occurs more easily as the heat from your home comes into contact with cold on the glass - this leads to dampness and mould in your property
• Lack of sound-proofing: single-glazed windows offer very little sound-proofing meaning you'll hear noise from traffic and passer-buys more acutely
• Security: it's far easier to break a single-glazed window than double or triple-glazed windows
• Decoration: due to the condensation, you'll most likely find yourself having to constantly wipe and clean away the mold, as well as repaint them more frequently as the dampness ages paint more quickly

If you have single-glazed windows, keep reading to find ways to help you better insulate them or consider whether it's worth replacing them.

Wooden windows 

As they're aesthetically pleasing, wooden windows can be a great addition to how your property looks. Wood is also a natural insulator which is ideal for energy-efficiency, and many people like having windows that come from a renewable and biodegradable resource. However, wooden windows do require maintenance; time and care is needed to prevent the wood from warping and their energy efficiency declining.

uPVC windows 

Low-maintenance, durable and largely resistant to weather, uPVC windows are often the most recommended style due to their moisture-resistant and non-corrosive properties, they can be cheaper to buy as well. However, older uPVC windows do lose their energy-efficiency. With age their seals degrade; this allows air to leak in, stops them from insulating and warps their frames, all of which lead to draughts.

Aluminium windows 

Modern aluminium windows can be a great energy-efficient alternative to wood or uPVC. New aluminium frames come with thermal breaks which insulate barriers between the frame sections and come as double or triple-glazed. As aluminium is recyclable and has a long lifespan, they're often viewed very positively. However, they can more expensive than either wood or uPVC windows.

Different types of energy-efficient doors 

Composite Doors 

A composite door is an external door made from a blend of materials, such as uPVC, timber, foam, or glass-reinforced plastic (GRP). A composite door is made to be long-lasting, secure, weather-resistant and importantly, great at draught proofing doors to stop heat from escaping. They often had a low U- value meaning they offer good insulation.

Wooden Doors 

Not only do they look attractive, but as wood is a good insulator, choosing a solid wood door is great for helping keep your home energy efficient.

uPVC Doors 

These are a popular choice as they last for a long time, are energy efficient and weather-resistant.

Aluminium Doors 

Often chosen for properties near the sea, aluminium doors offer protection from corrosion and don't expand or contract like wooden or uPVC doors can.

Energy ratings explained 

Window manufacturers use an energy-rating scale from A++ to E (like you see on white goods such as fridges or tumble driers). The frame and the glass are measured to give a rating that shows how efficient the window will be in your home. To choose the most energy efficient window, look for the BFRC rating.

U-values and R-values 

Window and door efficiency is also measured in values:

U-values

If your windows or doors have an energy rating, it'll be shown as a ‘U-value’ on the window's energy label. A U-value is shown in Watts per square meter per Kelvin (W/m²K). U-values measure how easily heat can pass through. For example, a window with a U-value of 0.2 is more energy-efficient than a window with a U-value of 0.3.

R-values

Conversely, an R-value measures a material's resistance to heat flow. The higher the R-value, the better a material is at preventing heat from passing through it, which means better insulation and energy efficiency for your home. For example, a window with an R-value of 5 is better insulated than a window with an R-value of 4.

How to check if your windows or doors are inefficient? 

Seal gaps

Check your window and door frames for obvious cracks, damage, gaps and seals - these can often be found around the frames or where they join a wall. Age and weather can cause these problems.

Condensation

If you've got condensation, misting or water between window pane glass, then this is often a sign of age and you'll be losing insulation. Your windows will suffer from this if they're single pane, and will be energy-inefficient.

Draughts

Usually, you can feel the cold air coming in through gaps in window frames or doors, but if you're not sure, carefully try holding a lit candle near the edges. If the flame starts to flicker, or even goes out, you'll know you've got a draught. If you don't have a candle, try using a torch with someone standing on the other side of the door or window. If they see tiny spots of light coming from the torchlight from the other side, you'll know you've got a gap.

Unit frames

If you find it difficult to open or close doors or windows, this can be a sign that the frames are warped and probably letting heat escape.

Energy bills

If you notice your energy bills are higher than maybe your neighbours, and you run similar-sized households, it may be a sign your doors and windows are no longer energy efficient.

Steps to reduce energy and heat loss through windows and doors 

• Invest in thermal curtains or blinds - both will help insulate your windows and help prevent your home from losing heat
• Draft excluders or stoppers are an easy way to seal gaps around frames and at the bottom of doors
• Sticking window film over your windows and frames can help your windows from losing heat
• Reseal your window frames and sill with weather-stripping or sealant to fill gaps
• Shutters attached to windows can help improve energy efficiency and also keep your home cooler in the summer
• Replace damaged window and door frames with new ones made from wood, uPVC or aluminium
• Install new double or triple-glazed windows with frames made from wood, aluminium or uPVC
• Replace old doors with new energy-efficient versions made from composite materials, wood or uPVC

Cost of improving or replacing doors and windows, is it worth it in the long run? 

While replacing windows and doors is expensive, especially if your property has a lot of large windows, the investment is rarely unwise. Even if you're looking to only stay for a short while, replacing these will add value to the property.

By replacing doors and windows with new ones, you'll:

• Improve the energy efficiency of your whole property
• Get reduced energy bills due to lower heating costs and heat loss
• Improve your property's EPC rating, which also helps with selling or renting it out
• Improve the value of your property - not only from achieving an improved EPC rating, but by enhancing your curb appeal with windows and doors that no longer look old or outdated
• A warmer and less draughty home
• Improved security from robust frames and modern locking mechanisms
• Reduced noise coming into your home, and from your home

Upgrade your heating system

While there are plenty of free ways to boost your home’s energy efficiency, investing in long-term improvements like adding insulation or switching to an air source heat pump can make a much bigger difference. These upgrades may come with a cost, but the benefits are greater, and you'll notice the impact more.

Looking for a simple change? Switch to EDF, the UK’s biggest provider of zero carbon electricity. We offer a variety of energy tariffs and special offers, and by joining us, you’ll be supporting Britain’s path to net zero.

Get an energy quote with us today.