As the climate heats up, more and more people will be turning on the AC to keep cool. By 2050, up to two thirds of households globally will have an air conditioner, and unless the energy to power these is from sustainable sources, more and more greenhouse gas emissions will be generated which will in turn, contribute to more global warming.
But there is a way to design buildings to keep a comfortable interior environment with resorting to AC. Here are some of the strategies we deploy at Leanhaus:
Windows and Shading
Opening windows is a common way people try to cool buildings – but air inside will be just as hot as outside. In fact, the simplest way to keep the heat out is with good insulation and well-positioned windows. Since the sun is high in summer, external horizontal shading such as overhangs and louvres are really effective. East and west facing windows are more difficult to shade. Blinds and curtains are not great as they block the view and daylight, and if they are positioned inside the window, the heat actually enters the building. For this reason, external shutters are preferable. Keep the shutters closed during the hot part of the day and open again when the temperatures drop.
Windows are generally the weakest link in a building envelope, so it is important to install high performance glass and framing that resists heat gain. For this reason we prefer to use UPVC frames, not Aluminium which acts as a thermal bridge for heat gain. Double glazing is preferable to single glazing when it comes to preventing unwanted heat gain. High performance comes at additional cost, but the price is continually dropping. You can expect the windows to last the life of a home and there will be a significant operation cost saving over this period.
High levels of insulation:
A house that is designed to act like an icebox (or esky in Australia) will provide the best buffer from a scorching exterior climate. Insulation acts to resist the passage of heat through a building envelope. The higher the insulation value, the greater the thermal resistance. Timber framing provides good thermal resistance with a lower environmental impact - much better than brick, stone, steel or concrete. Timber framing also allows us to pack the space between the framing members with high performance insulation, something that is not possible with mass construction types.
Natural Ventilation and air movement.
Even the slightest air movement can improve comfort levels on a hot day. As air passes through a room, it collects stale warm air and exhausts it outside. We improve natural ventilation by positioning doors and windows to capture cooling breezes, create layouts that enhance the passage of air and provide operable windows for it to escape. Ceiling Fans are a low cost way to generate air movement in a room - a slight breeze passing over your skin creates evaporation and reduces the perceived temperature of a space by several degrees. For this reason we provide ceiling fans in every living space and bedroom.
Greening the space around your home can reduce the heat island effect and provide a buffer from high temperatures. In addition to the shading potential of trees and plants, vegetation carries moisture which cools the air and creates a micro-climate around it. Garden beds and water features positioned adjacent to low opening windows can cool the air by a few degrees before it enters the home.