What are the best options for heating your home, both for your family and the planet?
Those of us who have spent time skiing in the snow-clad mountains on a sunny winter's day will have experienced something quite surprising: sitting in the sun in freezing air temperatures you can be
quite comfortable wearing just a t-shirt.
How can that be? The answer lies in the wide spectrum of energy radiated by the sun heating the bodies it encounters rather than the air surrounding them - with the effect that for bodies to feel warm the surrounding air does not have to be heated to the same level.
Add to this the fact that radiated heat is healthier than the other alternative, generating convection heat in the form of warm air, and we have a solution which can serve both us and the environment well in the heating of our homes. With a radiant heat source we are able to keep the indoor air to a lower temperature, saving energy in the process, and still enjoy a comfortable and healthy living environment.
The savings can be considerable, as 29% of the energy consumed in a typical New Zealand home is used for heating. And yet, research has shown that the majority of our homes are under-heated by international standards.
The World Health Organisation recommends that living areas are heated to 18 ?C , with 16 ?C overnight in the bedrooms.
In new house designs the use of passive solar principles can help to meet these temperature levels during much of the winter, using thermal mass floors (concrete, tiles etc) to store heat from the sun and give it back in the evening as healthy, radiant heat.
Unfortunately we don't have this option in our existing homes as they usually lack thermal mass. So what are the best options for heating our existing homes, creating warm and healthy living conditions and helping the environment in the process by reducing emissions and air pollution?
For rooms that we regularly use it is worth investing more upfront in suitable, fixed heaters which heat them effectively and cheaply, while for small rooms that only get used occasionally, electric heaters which are cheap to buy but slightly more expensive to run can often be sufficient.
The Energy Efficiency and Conservation Authority (EECA, energywise.govt.nz) provides useful help, including a heating size calculator, before making decisions for our circumstances.
The best options, in terms of costs, health and environmental effects are:
Radiant heaters:
Woodburner (10 - 11c/kwh)
Pellet burner (13 - 19c/kwh)
Convection heater:
Heat pump (5 - 9c/kwh)
Less beneficial are:
Flued natural gas heaters, which radiate heat but create greenhouse gas emissions ?Electric heaters, which create radiating heat ?but are only useful in small spaces.??The least beneficial ones, which are also among the most expensive, are:
Unflued LPG heaters, which create unhealthy living environments and
Open fires with an efficiency rate as low as 15%.
For more information on these topics Auckland Council provides free and independent eco design advice. ?Phone 0508 326-337.
What are the advantages of the best heating options and what do we need to keep in mind to run them effectively?
WOOD BURNERS
Designed to primarily produce radiant heat which will make the room they are in feel warmer than the air actually is. This makes them particularly suitable for large rooms with high ceilings and/or poor insulation and air tightness levels.
Their advantages are:
??low running costs
??little pollution
??heating large spaces and can heat hot water in winter through a wetback system. ?Keep in mind that
?firewood must be dry to burn most efficiently
?building consent for installation is needed and the choice of woodburner has to be from the Ministry for the Environment's list of approved wood burners. ? www.mfe.govt.nz/laws/standards/woodburners/authorised-woodburners.html
PELLET BURNERS
Their advantages are:
??the pellets are made from waste products and burn cleanly with little ash
?heat control (better than a wood burner)
?heating large spaces
?heating hot water in winter through a wetback system
??convenience - temperature and timing can be controlled with thermostat and timer controls.
Keep in mind that:
??they use a small amount of electricity
?won't work during a power cut
?in areas with air quality issues only authorised burners can be installed - see the Ministry for the Environment's list of approved wood pellet burners
?building consent is needed
?most wood burners and wood pellet burners generate more heat than is needed for one room. Heat transfer kits, which are designed to extract warm air from one room and transfer it into one or more other rooms, can assist with heat distribution. Heat transfer kits are available from DIY stores.
HEAT PUMPS?:
Their advantages are:
??low running costs when used properly
?convenience - temperature and timing can be controlled with the thermostat and timer controls.
Keep in mind that:?
?must be sized correctly ?look for the ENERGY STAR® mark to find the most efficient model
?they won't work during a power cut
??it may be uncomfortable to sit in the flow of air.
