Energy Smart Homes - Home Heating

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These heaters are designed to heat medium to large rooms or connected rooms. Some types can be used for cooling as well as heating. With a wide choice of models, there is scope to save energy and money in the longer term, especially if these heaters are used for long periods of time.

Electric

•	Reverse-cycle air conditioners work on the same principle as fridges and freezers (but in reverse) and are a type of convection heater. Rather than making their own heat from electricity, they use the electricity to pump heat from outside the building to inside. Even on fairly cold days, energy still can be extracted from outside air and pumped inside. However, reverse-cycle air conditioners may perform poorly when the temperature is less than about 4ºC (unless optimised for these conditions). These heaters provide between 2 and 3.2 units of heat for every unit of electricity used (depending on the star rating) and are therefore much cheaper to operate than other electric heating units and have a lower environmental impact. Reverse-cycle air-conditioners can heat and cool, but are sometimes more efficient at one than the other. Most room sized systems are given an energy star rating which enables their performance to be compared. They show a cooling rating in blue and a heating rating in red. While less efficient units may be cheaper to buy, they will cost more to run. On the other hand, the additional cost of a more efficient system is usually offset by reduced running costs. To compare the energy ratings of various reverse-cycle systems, visit the Australian Government's Energy Rating web site.
•	Floor heaters have heating wires set into the floor slab during construction or, if retrofitted, laid on top. Some types can also be fitted between the underlay and carpet. The heat is distributed by both radiation and convection and provides a very high degree of comfort.
•	Radiant panel heaters are similar to floor heaters but are designed to be fitted on ceilings or walls.

Gas
Built in gas space heaters generally have similar advantages to portable gas heaters but are available in sizes up to about 60 MJ/hr, which is equivalent to at least 12 kW.

These heaters must have a flue to remove the exhaust gases. While this can lower the energy efficiency in comparison with portable units, it is better for the air quality inside your home.

Most built-in gas heaters have energy star rating labels. The more stars the less gas used and the lower the operating costs. This also means reduced greenhouse gas emissions.

To compare the energy ratings of gas heaters, visit the Australian Gas Association's web site and look for the 'Directory of Certified Gas Appliances and Components'. This directory is produced on a yearly basis and contains information on the annual energy consumption and star ratings for particular gas appliances, including heaters.

Wood
Firewood is readily available in most areas and, if purchased in bulk, is reasonably cheap. However, it can be expensive if bought by the bag.

Woodheaters have been identified as a major source of Perth's winter air pollution. Burning dry wood and maintaining a bright-burning fire helps minimise the smoke produced by woodheaters.

Burning wood also releases carbon dioxide, one of the main greenhouse gases. If replacement trees are grown to absorb this, the overall effect will be neutral. However, burning wood does create air pollution and can reduce forest habitat for animals.

If you decide to purchase a woodheater, make sure it is manufactured to Australian Standard AS4013 as it is illegal to sell woodheaters that don't comply with the standard.

•	Slow combustion heaters are the most efficient woodheaters due to their airtight fireboxes and air-inlet controls. About 65-75% of the energy contained in the wood is converted to useful heat.
•	Potbelly stoves are generally not as airtight as slow combustion heaters and are about 40% efficient.
•	Open fireplaces may be romantic but are very inefficient and wasteful. Only around 10%-15% of the energy in the wood becomes useful heat, the remaining 85%-90% goes straight up the chimney. Many open fireplaces (as well as poorly maintained slow combustion and pot belly types) release smoke into the house - this can discolour walls as well as present a health hazard.