Click here to download a copy of the City’s draft Green Building Guidelines and other supporting documents.

Creating an energy efficient house

Reduce up to 70% of your total household energy needs by means of simple design principles that reduce lighting, heating and cooling needs. This is known as passive solar design.

• Orientate the longest side of your house to face north for light and sunshine.
  
• As the northern side of your house receives the most sun, the roof overhang should be longer (at least 40 cm to 60 cm) in length. Windows will be shaded in summer when the sun is high, while allowing the sun’s rays through the windows in winter when the angle of the sun is low.
  
• Window shutters, awnings or screens shade rooms by keeping the hot sun rays out during summer.
  
• A skylight in the roof allows natural light into the house on sunny days and eliminates the use of artificial lighting. Make sure that the sloping glass of the skylight faces north.
  
• Natural materials (stone, timber, thatch and clay), often obtained locally, are most suited to keeping the home cool in summer and warm in winter. Mud bricks are an excellent source of insulation.
  
• Floors made out of brick or concrete maintain comfortable temperatures in your house as they are good at absorbing heat during the day and releasing this slowly at night. These floors should not be covered with carpets as a concrete floor absorbs more heat than a floor covered by carpeting.
  
• Heat loss is ten times faster through glass windows than through insulated walls, so open the curtains during the day (let in the natural light and heat) and close them at night (keeps in the heat).
  
• Grow a deciduous creeper or tree over a veranda or yard. During summer, these leafy plants shade your house. When the leaves are lost during autumn, the bare tree lets the rays into the house (through the windows) during the colder months.
  
• Plant trees on the south, east and/or west of your home to provide shade during summer.
  
• A tin roof loses a lot of heat during the winter and gets very hot in summer. Insulate the roof and paint it white (reflects light and is therefore cooler) or use aluminium or other roofing materials.
  
• A ceiling and insulation in a small house can reduce your energy requirements by as much as 124 kWh a month – saving roughly R50,00/month.
  
• Install ceiling insulation fibre to keep your house cool in summer (reduces warm air conduction) and warm in winter (regulates the temperature of rooms and prevents heat loss).
  
• Ensure suitable ventilation for fresh air and cool breezes - rooms can be ventilated using airbricks, forced ventilation or by opening windows.
  
• Install efficient heating, ventilating and air conditioning (HVAC) systems if required and ensure they are efficiently used. Be sure to shade the air conditioning unit outside with a tree for example.
  
• Install a solar water heater – these are relatively expensive but result in substantial savings on your electricity bill (water heating is the biggest part of most household’s electricity use profile).
  
• Install solar (photovoltaic) panels on the roof to provide electricity to run low consumption appliances such as the TV, radio, lights and fridge.
  
• Install energy efficient light bulbs (CFLs) throughout the house. These are usually more expensive than conventional incandescent light bulbs, but have a much longer life-span and use far less electricity. They pay themselves back in a few months and are a very sound environmental choice.
  
• Used water or ‘grey water’ from sinks, baths and showers can be directed to water the garden.
  
• Rain water can be harvested from the roof and stored, or channelled to the garden.
  
• Eco-friendly building materials can be used, including reclaimed wood, recycled/composite plastic, non-toxic eco-sensitive paints.
• Consider switching to green electricity. Green electricity is generated from renewable sources such as wind, solar and wave power.
  

 Click here to download the 'ENERGY' section, or full version, of the Smart Living Handbook - a practical sustainability guide for people and households in Cape Town to make their homes safer and to save money and the environment.

Useful green building web resources:

Green Building, The
http://www.sustainable.org.za/greenbuilding

Green Building Council of South Africa, The (GBCSA)
http://www.gbcsa.org.za

South African Journal of Green Building
http://www.greenbuilding.co.za

Sustainable Living Centre
http://www.sustainable.co.za

US Department of Energy: Energy Solutions for Your Building
http://www1.eere.energy.gov/buildings/residential/

World Green Building Council, The
http://www.worldgbc.org

Acknowledgment: These “Energy Efficiency at Home” web pages are made possible by funding from the Danida Urban Environmental Management Programme (UEMP).

NOTE: Information on this page was acquired from a variety of sources (print and Internet) and the City of Cape Town cannot be held liable for any errors or misinterpretations whatsoever. The City of Cape Town is also not responsible for the content of external websites, nor does it constitute an endorsement of these websites. They are solely intended to provide additional information sources that may be helpful.