Doors & Windows

Use Less Energy

They may be useful, but doors and windows are a real issue when it comes to heating and feeling comfortable in our homes. There are, however, many ways to improve your fenestration, and they needn’t be costly – door socks are making a big come back (make your own!) and the thermal qualities and draughtiness of all glazing can be improved by the addition of insulating curtains, shutters, blinds (the latter must be fitted properly to prove effective against draughts), or relatively inexpensive secondary glazing.

Note: We would always advocate timber doors and windows over uPVC – see materials.

Draught proofing

Unless your home is very new, you’re probably losing heat through draughts around doors and windows, gaps around the floor, up a chimney or two, and a whole host of other little holes and cracks in the external envelope of your home.

Bunging up these gaps and cracks is relatively inexpensive, but could save £100 a year or more, and make your home feel much more comfortable besides.
Draught-proof your doors and windows using seals and excluders available from your local DIY shop, seal your skirting boards with a silicone sealant, cover letter boxes and keyholes, and fit chimney draught excluders, balloons, or pillows (black bags filled with screwed up newspaper work well) – but remember that they’re up there if you light a fire!

Particularly if you have sash windows, you may like to consider an overhaul of your windows by a professional. They will insert draught-proofing strips into the sides of the window sashes – this can cost up to £300.00 per m2.

Remember though, your draughty single-glazed windows are well-ventilated, and draught proofing may result in a marked increase in condensation.
After plugging up your gaps (leave all intentional ventilation open), you may find that your draught proofing efforts are so successful that you will have to introduce managed ventilation - although this is very unlikely in an old house.

NB: Always ensure gas appliances have adequate ventilation – check with your local gas technician if you are unsure.
If you do use chimney draught excluders, balloons or pillows, you should take them out when you’re not heating the house (from spring til autumn say) in order to properly ventilate the chimney stack. If you don’t, you may find dampness and mould forming within the chimney stack or on the chimney breast.

Replacement glazing

The Energy Saving Trust (EST) estimates that replacing your single-glazed windows with even B-rated double glazing could result in a saving of £170 and 680kgCO2/year.
If the window frames of your single glazing are in good or reasonable condition, you may like to consider having the glass replaced with double-glazed units, as well as having the window over-hauled – this will cost up to £400.00 per m2.

Replacing the whole window is likely to result in a more air-tight and better thermal result, which with the right care could last for over 100 years (see Materials) – however this will cost £500.00 per m2, or up to £1000.00 per m2 if you also need to replace your sash boxes.

If your house is currently uninsulated, and given the costs of replacement glazing, it is worth considering that 20% of the heat in your home is thought to be lost through the windows and doors, compared with 25% through the roof and 35% through the walls. (Visit our energy calculator pages to find out more). However, replacing old windows is an important aspect of ongoing house maintenance, and if you do it will undoubtedly make your home less draughty and more comfortable, which in itself is worth several degrees of heat.

Secondary glazing

A reasonable alternative to over-hauling or replacing windows is to install secondary glazing, which fits onto the window frames on the inside of the house - according to the Energy Saving Trust, this could still save up to £105/year on fuel bills.

Secondary glazing can be quite substantial, and cost up to £200.00 per m2, although one of our favourite solutions comprises acrylic panels and magnetic strips for £40.00 per m2 which is easy to fit yourself.

Secondary glazing ensures that the window’s thermal qualities are increased, but ventilation to the original window is retained, thus minimising condensation risks.
It does however render the window more difficult to open, can result in window ledges being covered (with the more substantial systems), and the acrylic panel solution demands that the panels be stored somewhere during the summer should you wish to be able to open the windows regularly – under the sofa makes sense!

Solar blinds, shutters and shading devices

In the UK even in the hottest summers, cooling isn’t really too much of an issue, although it may become more so in modern houses with high insulation levels, lack of thermal mass, and inadequate ventilation.
However, when it is hot it is worth blocking out as much of the sun as you can from your house, so as to keep the internal atmosphere comfortable without the need for air-conditioning units.
Having solar blinds, shutters or shading devices installed will of course do this, or you may like to consider growing a vine or other deciduous vegetation above or in front of south-facing windows. This not only blocks out the sun but has a cooling effect in itself – and looks good!

In contrast, during the heating months it is important to try and allow as much direct sunshine into your house as possible, thus replacing your energy use with passive heat!

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