How to save energy with windows
With soaring energy prices this winter it seems self-builders are weighing up the costs as they consider their next move. Energy-efficient, eco homes are an appealing option which offer lower running costs in the long-term.
Low-income homes in England have been given funding by local authorities and social housing providers with the aim of upgrading 130,000 homes. Double glazing, insulation, heat pumps and solar panels are all measures that could be funded.
Unfortunately, less help is available for those building their own homes. The Green Homes Grant, which launched in early 2021 to help homeowners make their homes more energy efficient, was scrapped after six months.
Funding big purchases in the home, such as windows, may be off putting for self-builders. However, rest assured that with schemes like Help to Build and thoughtful ways to reduce self-build costs, the goal of building your dream home isn’t out of reach.
Windows of opportunity
Windows play an important role in ensuring your home is thermally efficient. Not only choosing the positioning can play its part in solar gain but energy-efficient glazing ensures your home is kept warmer and quieter, and can significantly reduce running costs.
In a bid to tackle the UK’s climate-warming emissions, the UK Government is committed to delivering zero-carbon homes by 2025 through their Future Homes Standard, which was announced in the government’s 2019 spring statement. The aim of the Standard is to radically improve the energy performance of new homes in England to ensure they are future-proofed with low carbon heating and high levels of energy efficiency. Self-builders have to adhere to the Future Homes Standard, and the new building regulations which came in from June 2022.
When it comes to construction, the airtightness and energy efficiency requirements for thermal elements of windows, doors and walls will need to be improved.Windows need to achieve lower U-values (the measure of the overall heat transfer) and meet targets for primary energy, carbon emissions and fabric energy efficiency rates.
What kind of window options are available to save money and create a sustainable self-build?
Double and triple glazing
Energy efficient glazing covers both double and triple glazing.
These type of windows have two or more glass panes of glass.
Double-glazed windows have two sheets of glass with a gap in between each pane, usually about 16mm. Triple-glazed windows have three sheets of glass, and two gaps. The gaps between the glass panes are filled an inert gas such as argon. The air or gas is completely sealed.
How do you measure the energy efficiency of your windows?
Windows should have an energy rating. The energy rating system for double glazing is rated between A++ (the best) and E (the worst). Building regulations require all new windows to be at least C-rated. According to the Energy Saving Trust, by installing A-rated double glazing to windows in an entirely single-glazed semi-detached gas heated property, you could save £195 a year and 330kg of carbon dioxide.
The British Fenestration Rating Council (BFRC) verifies the energy performance of windows and doors in the UK. Look out for the BFRC rainbow rating name on the energy rating label of your window to show that its performance has been verified. In England and Wales, the easiest way to make sure your windows are fitted to the UK Government’s building regulations standards is to choose a reputable installer who is registered with one of the official competent person schemes.
Look out for U-values
The thermal efficient of windows is measured by their U-value. Windows that have an energy rating will have the ‘U-value’ of the window displayed on the energy label. This measures how easily heat passes through a material. The lower the amount of heat the material lets escape, the higher the U-value will be. This is not a complete measure of how efficient a window is. The overall label rating will give you a better indication of the window’s energy saving potential.
How to choose energy efficient windows
Glazing costs vary significantly depending on style and materials used. For example, hardwood frames are more expensive while PVC windows tend to be cheaper.
Saint-Gobain Glass manufactures some of the UK’s most energy efficient glass.
Planitherm is a range of modern, high-performance glazing for the home made by Saint-Gobain Glass. Planitherm glass doesn't just meet UK energy standards and Building Regulations, it exceeds them: offering better efficiency than traditional double glazing. Planitherm glass can be used to achieve the best possible U-values and Window Energy Ratings.
