Passive Solar – What Does It Mean?

Do you want a house that is filled with natural light in the summer without overheating, and minimises your heating bills in winter? ……….If you do, then a passive solar house is what you need.

Here are some of the things you should do.

Getting The Winter Sun Into The House

This means having most of the main living rooms facing North with lots of windows.

It also means making sure the Windows aren’t shaded by fences, trees etc.

Maximising Thermal Mass

This means having dense materials like concrete  and brick inside the house.

  • In winter the thermal mass heats up during the day and releases the heat during the evening.
  • During summer if you open the house in the evening/night the thermal mass cools and helps keep the house cool the next sunny day.

Ideas for increasing thermal mass include:

  1. Have the house on a concrete slab rather than stumps.
  2. Have tiles or a slate floor especially in front of the north facing windows.
  3. Feature walls and or fireplaces of brick.

Keeping the Summer Sun Out

  • Minimising West and East facing windows. These windows are the worst for heating up the house with the low morning and evening sun.   (In winter they hardly get any benefit from the sun)
  • Shading North Facing Windows.
    Typically the shading will be in the region of 1 m from the outside wall. It can be either deep eves, a veranda, or a pergola.

Minimise Heat Transfer

That’s transfer of heat from outside to inside in Summer days, and inside to outside in Winter.

To minimise heat transfer:

  • Provide good insulation to walls and ceilings.
  • Have small windows on the South Side.
  • Closing curtains at night in winter.

The first house we built in Australia was built according to these principles. Although we lived in it for 10 years we never felt the need to fit air conditioning. We didn’t require awnings on the windows or wanted to shut the curtains on hot days.

The above advice applies to Australia and other Southern Hemisphere Countries such as New Zealand and South Africa. If you live in the Northern hemisphere you need to have the Large windows on the south side of the house.

What Passive Solar ideas have Worked for you?

For more Green Ideas see Sustainability