Windows and doors contribute to a significant amount of your home’s heat loss. In fact, single pane windows can lose up to 20% of your property’s warmth, so you’ll be wasting hundreds of pounds every year. Even double glazing over 15-years-old will have lost the majority of its energy efficiency and heat will be escaping.

There are plenty of reasons to upgrade your windows:

  • Enjoy cheaper energy bills
  • Produce a smaller carbon footprint
  • Have a more comfortable home with no draughts or cold spots
  • Reduce noise pollution and keep your home in peace and quiet
  • Minimise condensation build-up.

Costs and savings for replacement windows will vary from home to home and are dependent on factors such as frame material and size. The energy saving calculator on the Glass and Glazing Federation’s website should give you a better idea of potential savings.

Window frame materials

When replacing your windows, there are three frame materials to consider:

  • uPVC frames: The nation’s favourite. These have a number of excellent attributes such as being weather resistant, hardwearing and durable. uPVC is the cheapest option for your window panes too.
  • Wooden frames: An environmentally friendly option with fantastic aesthetic appeal. However, wooden frames will require increased maintenance to keep them in tip-top condition.
  • Aluminium frames: The most expensive of the three, yet with the price comes incredible strength and resistance. Aluminium frames won’t rot, warp, crack or peel.

When deciding on replacement windows, look to the energy rating for guidance. Windows are rated from A-G, with A being the most efficient and G the least. Both the frame and glass are incorporated in the energy rating, which is governed by the British Fenestration Rating Council (BFRC.

What if I live in a Conversation Area?

Conservation areas are regions of national heritage and protected by local councils to ensure they maintain their original appeal. As such, property owners in conservation areas will struggle to have planning permission approved for a variety of renovations. This can include double glazing and other replacement windows. However, it is possible to resemble the original windows so speak to a local planning officer for more information.

Double glazing

Double glazed windows are superb insulators and can save you over £200 each year. Because of their fantastic energy saving qualities, double glazing is the standard in new build homes. If your windows aren’t double glazed, you’ll likely be losing up to 20% of heat through the panes.

Double glazing is aptly named, with two sheets of glass installed and separated only be an energy efficient gas spacer. The gas spacer tends to be one of Argon, Xenon or Krypton, with Argon typically the most popular. Not all double glazing windows are the same, so always be on the lookout for the BFRC rating between A and G.

With double glazing:

  • Slash your heating bills

The main reason for installing double glazing is the opportunity to significantly reduce energy bills. Energy bills have been on the rise for the last few years and better insulating your home is the best way to avoid extreme costs. With double glazing you can save over £200 annually.

  • Reduce carbon dioxide emissions

By improving energy efficiency you’ll be helping the environment by cutting CO2 emissions. Carbon is released when fossil fuels are burnt. With better insulation, your home won’t require as much heat, thereby fewer emissions are released.

  • Enjoy a warmer property

Double glazing not only prevents heat escaping your home. It also eliminates draughts and cold spots, ensuring a warmer and more comfortable environment for you to enjoy.

  • Keep your home in peace and quiet

Double glazing’s efficient qualities aren’t just useful for reducing energy bills. In the same way double glazing will retain heat, it’ll also keep sound out. Noise pollution can’t pass through the motionless gas spacer, so you’ll have a quieter home.

Energy Rating Detached home Semi detached home Mid terrace home Bungalow Flat
A rated £130-£175 £90-£120 £80-£105 £60-£80 £50-£65
B rated £120-£160 £80-£110 £70-£95 £50-£70 £40-£60
C rated £120-£150 £80-£105 £70-£90 £50-£65 £45-£55

Secondary glazing

Secondary glazing is a cheaper option to double glazed windows, but it won’t have the same level of energy saving qualities and money saving possibilities. You can save up to £100 annually with secondary glazing and it’s often recommended for conservation area homes and listed buildings.

Secondary glazing is essentially a second pane fitted to the inside of your original glazing. This means the exterior appeal doesn’t change, which is why councils often don’t have a problem.

If you’re on a budget, there’s also the option of fitting thin, transparent plastic film to the windows. This can be done yourself, so there’s not the expense of hiring a contractor. It looks similar to cling-film but when fitted it should be wrinkle-free and almost invisible.

Understanding U Values

The U Value is often mentioned when referring to a window’s energy efficiency. In layman’s terms, it’s the measurement of heat that can escape or be retained. Whilst the Window Energy Rating (WER) gives you a good idea on a scale of A-G, the U Value is a more accurate calculation.

The U Value calculates the rate in which heat will pass through a particular unit. This is known as thermal transmittance and the lower the U Value, the better the window’s efficiency. This is measured in W/m²K (Watts per square metre, per degree Kelvin).

The energy performance of your windows can be ascertained with heat loss and heat gain. Free heat can be gained from the sun, which passes through the window and is absorbed by internal fixtures. This is short wave radiation. Once heat transfers to long wave radiation it’ll try to escape your home through the windows, roof, doors, floors and walls.

This is why double glazing windows have a lower U Value as the energy efficient spacer blocks heat and prevents it from escaping.