Traditional windows do a great job of bringing daylight into our homes but are rather less brilliant when it comes to keeping the heat in. Although the simplest ways of reducing heat loss involve a sacrifice of daylight, there are also ways of improving the thermal performance of the windows of Cheltenham’s traditional homes without making them darker.


Daylight brings to our interiors not only illumination but also warmth and delight, a fact that the builders of the eighteenth century were quick to exploit in the distinctive form of the tall sash window. In the regency and Victorians periods, builders developed this design further, bringing yet more daylight into their principal rooms by lowering the sills and using large panes of plate glass instead of small panes divided by glazing bars. Consequently most of the traditional buildings of Cheltenham enjoy good daylight.

If any of your rooms seem dark during the day, do your best to maximise the daylight before you turn the lights on. If you paint internal window sills and window reveals white and use light-coloured finishes on the walls and floors, you will reflect daylight deep into a room and help to illuminate the parts of the room furthest from the windows. This is a relatively easy way to brighten a gloomy room. You should also ensure that your curtains or blinds do not hang in front of the glazing of the windows when they are fully drawn.

Hallways and staircases need to be properly illuminated to be safe but are sometimes the darkest spaces in traditional houses. A roof window may be an option here. Because they face the sky, roof windows provide around three times as much natural light than an ordinary window of equivalent size. However, before installing a roof window, consider the effect of the installation on the building and streetscape. Roof windows are a fairly common sight in Cheltenham but if you live in a street with a particularly consistent look to its roofs, the addition of a roof window could be disruptive. In these circumstances, install the roof window on a valley or back roof rather than on a street-facing roof if at all possible.

Heat loss

Windows lose heat both directly through the thin fabric of the glass and through the draughts that whistle through the gaps between the window and its frame. On average, 10% of heat losses are through windows but this figure is likely to be much higher in many traditional terraced houses which have large windows and no exposed side walls.

Heat losses through traditional windows can be reduced in the following ways:

  • Protecting windows with shutters, curtains and blinds
  • Renovating and draught-proofing windows
  • Installing seasonal or integrated secondary glazing
  • Installing double glazing

Replacing windows with new double-glazed units is often presented as the standard upgrade for old windows but this is not necessarily the best option. If you live in a house that has its original windows still in place, you may not want to lose them. If you renovate and draught-proof the windows, install seasonal secondary glazing in the winter months and always close your shutters and curtains, you will keep the heat in just as well at much lower cost.

However, in many traditional houses the original windows have long disappeared through decay, war damage or previous upgrades. In these circumstances, installing high quality timber double glazing which is sympathetic to the design of the house may be an attractive option.

As so much heat is lost through windows, the best option is always to combine measures. If you do install double glazing, don’t forget to close your shutters and curtains when the light falls.