How to Improve Bay Window Insulation

Bay windows are an attractive feature in a house, but they’re notorious for letting in cold and damp. Here’s how to improve your bay window insulation.

bay window insulation

Bay window insulation is something most people struggle with.  Bay windows (often single glazed) take up a large amount of wall space which is usually not insulated well, and rely on radiators to compensate for the heat loss.

As soon as there’s just a small gap in a building’s insulation you’ll start losing heat. According to a survey by NASA, a 5% insulation gap will account for 50% of overall heat loss. This figure could be higher for bay window walls which have single glazing and no insulation.

To improve your own bay window insulation, follow these easy steps.

Fit double or triple glazed glass

While this won’t help the insulation of the wall itself, you’ll be able to reduce how much energy is lost through the windows. Windows are commonly one of the largest contributors to heat loss in a house as it is impossible for them to ever be as effective as an insulated wall. This can be improved by replacing single glazing with double or triple glazing.

Fit interior bay window insulation

It’s a bit easier to fit insulation in a bay window wall without disturbing the design of it when it consists of cavities. But the intricate, awkward shapes often seen in bay windows make it a bit harder to fit insulation when the wall is solid. The exterior is often where most of the detail is, and fitting external insulation could damage this and make the exterior lose all its character. In this instance, you should fit internal solid wall insulation because there is often less detail found on the inside.

Remove bay window radiators

Most of the heat from a bay window radiator just escapes right through the wall if it’s not insulated. This can lead to extreme condensation problems caused by the heat hitting the cold surface of the wall. You may get some warmth in the room from the radiator, but as soon as it gets turned off you’ll notice it getting cold very quickly. Replacing the radiator with bay window insulation will reduce your energy bills, create longer-lasting warmth and reduce the amount of CO² emissions being produced by your home.

Consider thick, ceiling-to-floor curtains

This won’t be guaranteed to suit your décor, but it will add another layer to your bay window insulation. Ceiling-to-floor curtains which are lined with fleece will cut out further heat loss and the amount of cold air coming in. Please bear in mind that this is an additional insulation method, not a replacement one. You’ll still need to fit good insulation in or to the wall if you want to make a noticeable difference.

If you’re confident of your DIY ability, check out this article for some further bay window insulation techniques.

Image: Claus Wolf

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