East or West facing windows let in the summer sun and each square metre of unshaded window heats your home by the same amount as a one bar radiator. In a living room with west-facing windows with blinds – but no external shade – the room can be up to 3 degrees hotter for several hours, than the same room with awnings over the windows.
External shading is best
There are many options to choose from when shading windows – both internally and externally. However, it is important to consider that external shading is more effective in reducing heat. A curtain or blind on the inside of a window will reduce heat by around 35%, however shading the outside can reduce to heat by up to 80%.
Some options for external shading:
- Plant trees or tall shrubs: this is a very effective and low cost solution that looks great! However, you need to make sure you have adequate space for the trees or shrubs to grow away from the house. Your garden can really help reduce heat around your home. Try and avoid paving on your north, east or west facing windows as it soaks up heat during the day and radiates it at night. Try a ground cover or shrubs alongside walls and windows instead.
- Shaded pergola or sail structures: these are very effective in summer and also can be removable in winter. They also provide a shaded outdoor living space, however again you need to ensure you have the space to build out from the house.
- Window tinting: this is a great option if you don’t have much spacing for planting or to build a shade structure and can be applied to any window. However, window tinting does reduce light all year round.
- Roller shutters: these will reduce heat loss in winter as well as heat gain in summer and are adjustable at any time of the day. They also can improve security and noise control, however are a more costly option that some others.
- Awnings or external blinds: these require minimum space to be installed, so can be a good option for tighter areas. They too are adjustable for the time of day and season and are often slightly less expensive than roller shutters. However, they may not fit on all window types.
- Shade cloth: for a very low cost solution, simply hanging a roll of shade cloth from the eaves will also be very effective!
Amount of heat blocked compared to unshaded glass