A Guide to Energy-Efficient Wood Windows

Wood windows are a particularly elegant and energy-efficient feature for your home. When manufactured to high standards, they are even likely to surpass the expectations required by Building Regulations. If you have been thinking of getting energy-efficient wood windows for your property, you will find out everything you need to know about them here.

Why Are Wood Windows Energy-Efficient?

Wood windows are energy-efficient because timber is a natural insulator, meaning it absorbs and retains heat before releasing it slowly. This helps to keep interior spaces warmer for longer, and means thermostats do not have to be turned up as high and energy usage is reduced. This also saves money on energy bills.

How to Make Old Wood Windows Energy-Efficient

Windows do lose energy efficiency as they get older. If you have an old set of timber windows and you are wondering how these can be made more energy-efficient, follow these tips:

• Repairing or replacing old timber window frames with new ones is often less expensive than replacing the windows entirely. It also ensures the frame material is strong enough to hold double or triple-glazed panes of glass if you decide to use these.
  
• Checking the locks you have on your existing windows may help to ensure you are sealing the windows securely each time. Making sure the windows lock without leaving gaps ensures cold air is not being let in by accident.
  
• Replacing single glazing with double glazing is the most common and popular method of ensuring the energy efficiency of windows. Old double-glazed units are also less energy-efficient and should be replaced every 15 to 20 years, on average.
  
• If you have old double-glazed windows, consider replacing these with triple-glazed windows. Depending on the installation, triple glazing is likely to be at least 20% more efficient, and can be up to 40% more efficient than double glazing.
  
• Organic materials like wood might warp over time, which has the potential to create gaps that can let cold air in. Checking if this has happened in your windows can help to determine energy efficiency, and tell you if the windows need draught-proofing.
  
• Apart from replacing the frames to close gaps, you can always use heavy curtains or roller blinds, as well as other coverings, to help draught-proof your home. To see a full list of the most energy-efficient window coverings, please take a look at our page.
  
• If you do not want to install double glazing, you can choose to have secondary glazing fitted. This is a second sheet of glass added to a window, with an air gap in between it and the original window instead of the typical layer of argon gas.

Calculating Energy Efficiency in Wood Windows

There are two specific methods of measuring the amount of energy saved from timber windows:

• U-values: These are a measurement of the rate of heat loss through a material. All windows have a U-value, and most manufacturers quote “whole window” U-values, measuring heat loss through the entire window. The lower the U-value of a window, the more thermally efficient it is.
  
• Windows Energy Ratings (WERs): This method of measurement was originally launched by the British Fenestration Rating Council (BFRC) in 2004. It is based on a rating system with a scale of G to A+, with A+ being the most energy-efficient. It is generally more popular because it is considered a simpler method for most.

How Energy-Efficient are Wood Windows?

Wood windows boast exceptionally low U-values and can improve thermal insulation in a home significantly. Timber window frames often receive “A” energy ratings when measured using WERs, which means that they could save homeowners up to £160 a year in energy bills, according to experts. This amount may decrease depending on the type of property, but having energy-efficient wood windows is still considered an excellent way to save money.