Energy Efficient Homes
A sustainable home achieves its goals in tow ways:
- Using eco-friendly resources and technology to harness energy
in the home
- Reduces the use of energy [electricity] in the home.
The major impact of electricity usage is not in the home, but in
the production of electricity at power stations. Many burn fossil
fuels which damage the environment and increase the carbon footprint
of a nation.
Using energy efficient
appliances in the home is one way of reducing electricity usage
and, therefore, carbon emissions.
The definition of a 'low-energy house' continually changes. At
present, a low energy house is considered to be one that uses around
half of the German & Swiss low-energy standards for space heating.
This is typically 30 kWh/m²a to 20 kWh/m²a (8,000 Btu/ft²/yr
to 6,000 Btu/ft²/yr).
Energy usage below this level is referred to as an 'ultra-low energy
At the extreme we have zero
energy buildings, that on average over a year, use no imported
energy, and may even generate a surplus [energy plus houses]. These
are also referred to as autonomous buildings.
Whatever degree of low
energy rating a home achieves, it is generally done though a
combination of energy conservation technologies and the use of renewable
energy sources. In the absence of recognized standards, the energy-use
profile and environmental impact of a building can vary significantly.
Low-energy buildings typically use:
Home Energy Rating
Energy assessments for each country, and region within that country
account for different climatic conditions and are benchmarked according
to average household energy consumption for that region.
In Australia, A 5-Star rating indicates that the house has achieved
a high level of thermal energy performance, and will require minimum
levels of heating and cooling to be comfortable in winter and summer.
Such homes are generally more comfortable to live in, have lower
energy bills, and lower costs to install heating and cooling equipment.
The house energy rating does not currently include the
efficiency of any appliances fitted or used within the house.
Passive solar building design
has proven energy consumption reductions of 70% to 90% in many locations,
without employing any active
power generation systems.
With expert design, this is achieved with little additional new
construction cost over a conventional building. The limiting factor
is widespread usage is the lack of industry skill and experience
to both design and install such systems. Passive solar designs are
much more cost effective than adding expensive PV panels on the
roof of a conventional inefficient building.
Next: Energy Efficient
- A few kWh of PV panels (costing tens of thousands of U.S. dollar
equivalent) may only reduce external energy requirements by 20%
- A 100,000 BTU high seasonal energy efficiency ratio 14 conventional
air conditioner requires over 7 kW of PV electricity while it
is operating, and that does not include enough for off-the-grid
night time operation.
- Using passive cooling, and superior system engineering techniques,
can reduce the air conditioning requirement by 70% to 90%, where
PV electricity then becomes cost-effective. (Energy conservation
PLUS energy generation)
Back to Top
Sustainable Homes Index | Defining
Sustainability | Energy Efficient Homes
Energy Buildings | Sustainable Home
Design | Energy Efficient Appliances
| Heating | Active
Solar | Passive Solar | Solar
Water Heating | Geothermal
| Lighting | Water
Management | Updates