Don't lose too much heat through your dog door!
How can we change the general public's behaviour?
Buying a heater.
Editors note: My apologies for the delay in this months CoolComfort Tips. I had to relocate my web site and have only just got the new site up and running. The new address is http://www.coolmax.com.au. (The difference is it doesn't have the mx in there any more.)
You will need to alter your bookmarks as the old location will shortly disappear. If you have an air conditioner, I recommend you bookmark it for the troubleshooting guide. (Air conditioners always breakdown on a weekend during a cold snap or a heatwave, when you can't get hold of a service technician.) If you don't have an air conditioner I recommend you bookmark it for the advise on buying an air conditioner.
If you do find an error when checking out the revised site, please let me know so I can fix any teething problems.
For full details visit http://www.coolmax.com.au/air-conditioning/size-calculator.htm
You can lose nearly as much heat around the gap in a dog or cat door, as you can under the bottom of an outside door. If buying a dog door, see if you can afford one of the more expensive doors with seals. Most of the heat loss is through the gap around the flap. If you are moderately handy you may be able to improve a poorly sealing dog door with a lightweight brush type door seal.Back to Contents
One thing that all people concerned about energy use in residential buildings agree on, is that people's behaviour is critical to achieving low energy use. People's behaviour is important at different times for different reasons, for example:
When buying a house, the energy efficiency of the house is only a minor concern, relative to things like the size of the bathroom, etc.. However it should still be factored into the equation. In practice only a few people consider it at all. The ACT has required the disclosure of the house energy efficiency rating on the sale of a property for some time. Unfortunately there is a mixed reaction to this scheme. I think this is more due to the feeling that many of the ratings are invalid because they aren't done properly, rather than a problem with the concept. The evidence in the ACT is that it does affect house prices, so if the problems in the scheme can be ironed out, it should be rolled out around Australia.
Heating and cooling appliances have star ratings, and no doubt the readers of this newsletter, buy the most efficient that is affordable, but how do we get the general public to behave the same way. Research suggests that star ratings do alter some peoples decisions, but many buy on first cost regardless. Currently the rating labels have an estimated energy usage, however most people would find it difficult to translate that into a running cost. I think that we should be putting an estimated annual energy cost figure (or ten year annual energy cost figure) on the rating label. This figure would be only indicative, as you couldn't fit figures for every climate on the label, but might drive home the message more strongly at the time the person is making the decision.
Finally we come to the day to day decisions that affect energy use. Things like closing doors to unoccupied rooms. We don't want to become energy Nazis, but how do we get others to adopt the behaviours we want? I don't have the answers, but I will make some suggestions as thought starters.
If you have any comments please Mailto:Back to Contents
When buying heating and cooling equipment, look closely at the star rating (where available). There is quite a range of star ratings available at the moment, but often you can recover the extra cost in a year or two due to lower running costs. However star ratings don't always tell the full story, so read on to find out some inside information!
Bear in mind too that all the forecasts are for energy costs to rise, even though some areas have seen falls over the last few years.
Natural gas combines very effective performance with good running costs. (Contrary to popular opinion, an efficient gas heater has similar running costs to an efficient reverse cycle heater in most areas.) If you don't have piped gas, the running cost is higher but is still worth considering.
The cheapest gas heaters are small un-flued heaters. Unfortunately the combustion products are released into the room. The testing for star rating treats the heater in isolation and doesn't take into account that you need ventilation when operating an unflued heater. This ventilation means the often very high star rating of an unflued gas heater is meaningless. If it is at all possible use a flued heater.
Flued console heaters are a good option for small to medium rooms. For a given star rating, a heater which heats by both radiation and convection will use less energy than one that heats by convection alone. This is because radiant heating will heat you directly, instead of heating the air first.
Gas wall furnaces are a good option for larger areas.
Underfloor ducted gas heating gives an exceptional level of comfort, particularly in cold climates. This is more effective than in ceiling ducted gas heating, but in ceiling ducted gas heating is usually very comfortable.
A slow combustion heater is generally the preferred method. Look for a more efficient model. If you are buying the wood, an inefficient model will use more and cost more. If you are cutting the wood yourself you want to make the task as easy as possible! Pot belly stoves are less efficient and open fireplaces are very inefficient.
Shouldn't be ignored, especially in a small well insulated room, or for very occasional use. (For example a guest bedroom which is only rarely used.) My office is heated by a 375W under-desk heater which is fine except in the coldest conditions. The running cost of this heater is relatively low, because the heat is supplied only where it is needed. However in large or poorly insulated areas, they are likely to be expensive to run and provide very little comfort. You also need to be careful about what other items are on the same circuit, as you may trip the circuit breaker if you are also using the dishwasher and electric jug at the same time.
Radiant heaters are more energy efficient than convection heaters, although convection heating is more even. This means the convection heater is more comfortable, but will cost more to run. As with small gas heaters, a combination of radiant and convection heating is generally better to get the advantages of both types. I strongly recommend you buy a heater with at least two heat settings, as you should find that most of the time the lower setting is enough, saving you money.
I consider oil filled radiators to be expensive to run, slow to heat the room and I generally don't recommend them. A fan heater will generally give a quicker warm up, and use less energy.
Storage heaters (running on a night tariff) are feasible in some areas. Look for a company that specialises in them to get the best possible advice. The running costs are low if they can be run on an off peak tariff, even though the actual amount of energy used (and greenhouse gas produced) is greater. They are most appropriate in a house where you need heat all day. Similar comments apply to underfloor electric heating if you are building a home.
Don't expect a reverse cycle air conditioner to give perfect conditions when heating. The air is supplied at high level and thus tends to cause hot faces and cold feet. However if you have a mild winter and you don't have natural gas it may be a good option. This is particularly the case if you live in a humid climate (Sydney, Brisbane or similar) where the option of using evaporative cooling in summer is not viable. Pay particular attention to the star rating and remember Inverter air conditioners are likely to use 30% less energy than other air conditioners of the same star rating. (Inverter air conditioners also give a more even temperature).Back to Contents
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For full details visit http://www.coolmax.com.au
Web page: http://www.coolmax.com.au