Heating homes with sunlight, known as passive-solar heating, is based on the simple idea of using north-facing windows to admit low-angled winter sun. Sunlight streaming into the home warms the interior space. Thermal mass, such as tile floors and interior masonry walls, stores the sun’s heat and releases it when room temperatures fall at night or during cloudy weather.
Choose a house design that accommodates the right amounts of north-facing glass and thermal mass. Add ample insulation (usually slightly higher than building codes currently require), and you’ll have a solar heated home that requires little or no heat from any nonrenewable fuel source. In the summer, a solar home’s thermal mass and insulation, together with properly sized overhangs to shade the windows, keep the home comfortable and reduce cooling requirements.
Simply orienting a conventional house to the north will cut annual energy bills by at least 10 percent, saving thousands of dollars over a home’s lifetime. Add a long north-facing wall of windows and some thermal mass and you easily can tap sunshine’s free energy to meet 50 percent to 70 percent of a home’s heating requirements. Given the probability energy costs will increase steadily in the coming years, the long-term savings from a passive solar home could become very substantial
All this can be achieved with a well designed house plan. At Paton Constructions this is all part of the building process.
There are eight climate zones for thermal design within Australia.
Canberra falls into the “Cool Temperate” Zone.
Low humidity, high diurnal range.
Four distinct seasons. Summer and winter exceed human comfort range, variable spring and autumn conditions.
Cold to very cold winters with majority of rainfall. Hot dry summers.
Recommended use of these passive solar principles.
High thermal mass is strongly recommended. Insulate thermal mass including slab edges. Maximise north facing walls and glazing, especially in living areas with passive solar access. Minimise east, west and south facing glazing. Use adjustable shading. Use double glazing, insulating frames and/or heavy drapes with sealed pelmets to insulate glass in winter. Minimise external wall areas (especially east and west). Use cross ventilation and night time cooling in summer. Site new homes for solar access, exposure to cooling breezes and protection from cold winds. Draught seal thoroughly and provide airlocks to entries. Install auxiliary heating in extreme climates. Use renewable energy sources. Use reflective insulation to keep out heat in summer. Use bulk insulation to keep heat in during winter. Bulk insulate walls, ceilings and exposed floors.
Passive design is design that does not require mechanical heating or cooling. Homes that are passively designed take advantage of natural climate to maintain thermal comfort.
Incorporating the principles of passive design in your home:
- Significantly improves comfort
- Reduces or eliminates heating and cooling bills
- Reduces greenhouse gas emissions from heating, cooling, mechanical ventilation and lighting.
Building envelope is a term used to describe the roof, walls, windows, floors and internal walls of a home. The envelope controls heat gain in summer and heat loss in winter.
Its performance in modifying or filtering climatic extremes is greatly improved by passive design.
Well designed envelopes maximise cooling air movement and exclude sun in summer. In winter, they trap and store heat from the sun and minimise heat loss to the external environment.
The fundamental principles of passive design, explained above are relatively simple and can be applied to the various climate zones, house types and construction systems in Australia. To explain all of these combinations in sufficient detail, information has been divided into separate fact sheets as follows:
This information is from Your Home A joint initiative of the Australian Government and the design and construction industries
Design and siting are crucial to building an energy efficient home in the Canberra region. By making use of our clear, sunny winter days and relatively cool summer nights it is possible to build a comfortable home that does not require active sources of heating and cooling.In wintertime this means maximising north facing window areas to allow the sun’s energy (warmth) into your home. This energy must then be stored in internal thermal mass such as a concrete slab floor or areas of internal brickwork. The stored energy needs to be retained through the use of good insulation in the external walls and ceilings.
In summertime this means minimising the effect of the hot summer sun through use of roof overhang to shade windows. West facing windows should be minimised and well shaded and external walls and ceilings need to be well insulated. Cooling the home’s internal thermal mass overnight through good cross-ventilation helps to keep the interior cool the following day.
Using these simple criteria will keep a house warm in winter (15-25°C) and cool in summer (20-28°C) without the need for heating or air conditioning.
Today there are also many new appliances and fittings available that will enhance the energy efficiency of your home such as solar hot water systems, water efficient fittings and back to grid solar panels.
Visit the gallery of homes we have built here in Canberra.