What can you do to save energy in your home, particularly if you have an older property? According to the British Blind and Shutter Association, blinds and shutters are a practical and affordable measure.
When energy was cheap and plentiful we did not think of how we should use the everyday things that could save energy. Just through behavioural change and therefore at no extra cost, a building’s energy consumption can be reduced by up to 10%. Solar shading, often thought of as the decoration of the window only, should be part of this energy saving strategy.
Blinds and shutters act as an extra layer of insulation for windows, helping keep heat in during the winter. Windows, particularly single-glazed and older double-glazed units, are poor insulators – meaning that precious heat can escape. Blinds and shutters can help reduce this heat loss, saving energy, money and increasing the comfort of your home.
Research conducted by Glasgow Caledonian University has shown that a reflective roller blind is as effective as a pair of curtains in reducing heat loss on single glazed windows. Both reduced the amount of heat lost by 40%, which is great news for heritage properties where glazing cannot be changed.
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It’s all to do with U-values. The lower the U-value, the slower the heat loss through the material. So a material with a low U-value is a good insulator.
The best U-value of a heat retaining (low emissivity) glass is around 1.2. As a comparison, building regulations say that walls need to have a U-value of 0.3 (about four times better) and roofs 0.18 (about six times better).
Even with modern coated glazing designed to retain heat in the winter, blinds and shutters can still offer an improvement in U-value, although obviously the effect is less dramatic than with older windows.
Generally, the better insulating blinds are those which are thicker, have reflective coatings, and have air gaps or pocket-like honeycomb fabrics. Blinds fitted in a cassette or frame will improve insulation, as these reduce gaps around the extremities of the blind. Wooden internal shutters are also good insulators, as are some external shutters.
One of the traditional ways of minimising the heat gain in buildings is to take advantage of nature and plant trees outside your windows. In the summer the leaves provide shade (just like shutters) and in the autumn when they shed their leaves the sun will be able to enter the building and provide natural winter heating. When we go on holiday to say Italy or Spain, we tend to do the same as the locals and close the shutters on the windows in the early morning to keep the excessive heat out. Later in the day the room is a cool refuge from the summer heat. This is another traditional and efficient method of keeping houses cool without using energy. Summer months in the UK can also get very hot. Many of our buildings are designed with large areas of glass and as a result will need cooling with either fans or air-conditioning systems to keep them pleasant and comfortable. This unfortunately uses energy and costs us money. Instead, we should look for ways of utilising passive cooling methods available, like planting trees and installing solar shading.
A significant amount of heat can be lost from a building during the cold winter months especially through the windows as they tend to be the weak point in the building insulation. The low angle winter sun can help us maximise the heat gains and blinds and shutters play an important role in reducing the amount of heat lost. They can be raised to maximise the solar energy entering the building when the sun shines and closed after sunset insulating the building throughout the night. This means less heating will be required in the morning to get the building to a comfortable temperature and less money will be spent on the heating bills.
One BBSA member installed reflective blinds in a domestic building along with advice to the owner that if he closes the blinds in winter after the sun has gone down, he will reduce heat loss, keep more heat in and save energy. The owner monitored his central heating carefully and found that after having the blinds installed he was able to switch his heating on an hour later than usual therefore saving energy and money.
Your local BBSA member will be able to offer expert advice.
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