With winter well and truly with us and temperatures plummeting (brrrrr), you might be looking for ways to keep your home a little cosier. Believe it or not, the cleanliness of your windows could help.

‘Solar gain’ is the term for the warmth generated by the sun’s rays within a home that is either produced indirectly (i.e. heating up of materials in the construction of your home which then radiate heat to the inside) or directly through its windows.

There are pros and cons to this solar gain. Obvious pros are lower heating bills and warmer homes in winter when heating systems may struggle. Obvious cons are overheating in summertime. and where windows are located as you can only have direct solar gain when you have glazing that faces the sun.

In winter you want to maximise the solar gain you can achieve to make your home warmer. Here are a few things that could hold you back:

  1. Obstructions. Trees offer wonderful shade from overheating due to solar gain in the summer, but could they be preventing the sunlight entering your home in the winter too? Evergreens keep their leaves all year round and offer as much shade in the winter as summer, preventing solar gain. If your trees are between you and the sun’s rays consider speaking to a tree surgeon about moving them or pruning to minimise the disruption or replace with a deciduous variety.
  2. Reflections. Direct solar gain relies on the sun’s rays entering your home through glazing, so reflective surfaces and elements in your windows, skylights and conservatories will reduce the solar gain you can benefit from. White frames can reflect sunlight away from the home and the more spacer bars you have within your glazing (reducing the glazed surface area) the more reflective your windows become.
  1. Materials. The higher the iron content in your glazing the less sunlight will pass through it ­while the lower the iron content the more sunlight will pass through, so the material your windows are made from can make a difference to solar gain as well.
  1. Gasses. Double and triple glazing often comes with gases between the layers, often argon or krypton. Their purpose is to reduce the amount of heat loss by reducing the ‘conductive heat transfer’. While this is designed to stop heat getting out it also reduces thermal gain getting in.
  1. Cleanliness. The dust, grime, bird droppings and pollution that dull your windows will also reduce its solar gain capacity. Just like the gasses in double glazing they will slow the path of the sunlight or reflect it away. You may not be able to do much about the orientation of your windows, or the materials and gasses in your windows, but keeping them clean is something you can do to improve the solar gain your home will receive throughout the long winter months.

A professional clean will ensure a smear-free sunlight-welcoming surface for longer to help you create a snug and warm home this winter. As we’re all going to be spending more time at home, this is one little thing you can do to make the experience just that little bit more comfortable.

For all your window cleaning needs, call London Window Cleaners 020 3954 2900.


  1. https://www.greenspec.co.uk/building-design/windows/

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