Upgrade windows to improve insulation

Upgrading your windows can help you keep out unhealthy draughts and noise, make your home more comfortable and save you some money on your energy bills.


Replacing old windows with new higher performance models will substantially cut this heat loss. This makes the room more comfortable and easier to heat. It can also cut your heating bills by £195 a year (A-rated double-glazing) and £235 (A++ rated double-glazing) if your current windows are single glazed. New windows may also help if your home regularly overheats in the summer months.

If a window is obviously damaged, or doesn’t fit properly, or if the glazing unit has misted up on the inside, then it could be time to replace it. You’ll need to replace it sometime soon anyway – if you replace it now then you’ll benefit from a warmer room sooner.

Double glazing costs vary significantly depending on the materials and style. PVC windows tend to be cheaper, while hardwood frames are the most expensive. A set of A-rated windows for a semi-detached house will typically cost around £7,500 according the the Energy Saving Trust.


Check whether you need planning permission

You don’t need planning permission to replace windows in most homes. If you live in a conservation area or a listed building, then there will be restrictions on what you can and can’t do. But if you already have double glazing then the restrictions may be less rigid, or may not apply. Check with your local planning office before making any decisions.

Find an installer

All window replacements have to comply with building regulations. Windows are normally fitted by a member of a relevant competent person scheme to make sure they comply with building regulations. Your installer will usually provide the windows for you and offer you a choice of different styles and layouts of window. Make sure you ask them about the window’s energy rating which could be somewhere between C and A++. Don’t buy any windows without energy labels.

You can find a local installer via Fensa or DGCOS or through our Open Eco Homes suppliers directory.

Choose your energy performance

A++ is the highest rating currently available. If you want efficient windows then you should ask for a rating better than C. Generally, any double glazed window is likely to be more energy efficient than a single glazed window. However, some double glazed windows are better than others, and triple glazed windows can be better still. The energy label is there to help you navigate and compare the performance of different models without having to worry about the details. The Energy Saving Trust provides a good overview of energy efficient window solutions on their website.


Open Eco Homes Directory: Our Open Eco Homes directory includes links to insulation products and suppliers used by our case study eco-homes.

Energy Saving Trust: offer advice on installing energy efficient windows and doors.