Energy efficient heating is, in many countries, not as highly emphasized as it should be. The energy losses due to poor insulation and wrong heating choices can be huge. According to David MacKay’s excellent Sustainable Energy – without the hot air book, heating and cooling accounts for almost 20% of every developed country citizen’s energy consumption (37 kilowatt hours per day out of an estimated total of 195 kilowatt hours per day per person). Admittedly, this percentage is a mean number for the UK and in other areas more air conditioning would be needed, but in this areas less heating is also needed thus keeping things slightly balanced. As 20% is a rather big percentage and 37 kilowatt hours is a lot of energy, it is very reasonable to try to increase the efficiency of heating solutions (and air conditioning for warmer countries like the one I live in). This can be achieved by using more energy efficient heating devices, as well as improve insulation and using heating a bit more wisely.
Here, I will try to cover all of the above aspects of energy efficient heating, although the list of solutions presented here is by no means exhaustive. I will assume that when heating or cooling a room or house, you close all the windows and doors. I very often see people who leave a window open when using air conditioning “because it dries up the air“. Great thinking, way to go throwing all energy saving efforts your architect and air conditioner company has made out the window. Literally. The same holds for energy efficient heating too, of course. As David MacKay puts it, “the most important smart component in a building with smart heating is the occupant“.
Cheap Tips
Draft check – When talking about energy efficient heating, one of the most important goals is to minimize heat losses. Choose a breezy day, and go around windows, areas where plumbing and wiring go through walls, attic doors, entry doors and fireplace dampers. with a lit stick of incense (or anything else that produces smoke, but incense smells nice). If there is a draft, you will see a change in the way the smoke is rising. The bigger the change, the larger the draft, obviously. If you find little gaps you can easily close them with some silicone. For larger gaps it is best to use some kind of insulating foam which expands to fill the whole gap. In any case, close the gaps from the outside of the wall to prevent moisture from building up inside the walls. To insulate the the gaps under doors, you can use door sweeps and draft guards which can be easily installed and cost less than $10 in most cases. You can go even further by checking your wall outlets for drafts and closing them up with outlet caps. This makes them safer for your kids too, if you have any.
Plastic window kits – Instead of changing all your windows with double glazed ones, which can be very expensive, a cheaper alternative are plastic window kits. They contain sheets of plastic film, which looks like cling-film, but slightly thicker. Double-sided tape is applied to the window frame, then the plastic is cut to size and fixed to the tape. Finally, a hair dryer is used to shrink the plastic sheeting tight. Just like with double glazing, an air tight gap is created which insulates the window, although not as effectively as a double glazed window would.
Less Cheap Insulation tips
Double glazing – Since windows and doors are the most common exit routes of hot air, it makes a lot of sense to try to insulate them as good as possible. If your windows are old, and particularly if their framework is wooden and worn out, replacing them with aluminum frame double glazed windows will make a big difference. The U-factor (i.e. the rate of heat loss) for a standard double glazed window is around 2.84 W/(K·m2), while the U-factor for a single glass is 6.25 W/(K·m2) (source: Insulated glazing). That’s almost 3 times more! Triple glazing windows also exist, which can have a U-factor as low as 0.8 W/(K·m2).
Cavity-wall insulation – This is especially effective for energy efficient heating if you live in a brick laid house, where many cavities exist (or are created later on due to corrosion etc.). By insulating the external cavities of your walls, you can greatly reduce your building’s heat losses. However, this procedure is rather difficult if you try to do it yourself, and pretty expensive if you get someone to do it for you. In the long run, however, you will eventually save money (and maybe Earth, too).
Efficient Usage
Efficient central furnace – If your home is heated by a central furnace, check the filters every month during winter. If it is full of debris, dust and other stuff, it will immensely reduce its efficiency. Additionally, you can shut off the pilot light during the summer months, check the chimney and furnace vent system once a year for obstructions or corrosion and have it regularly serviced so it works at its peak efficiency.
Efficient wood stoves – If you heat your home with wood it is important to be as efficient as possible, both for the energy savings as well as the health benefits. Always clean your heater at the beginning of the heating season and periodically thereafter. The air intake duct should be clear of webs or debris, the chimney inspected and excess ash removed from the firebox.
Turning down the heat
The thermostat – An extremely simple, yet astonishingly effective, device which can help you enormously in consuming less energy to heat your home (or workplace). By turning the thermostat down, not only do you obviously reduce the energy expended in heating, but you also reduce your home’s heat losses by about 10% for each degree Celsius due to the reduced temperature difference with outside. So, energy savings come from two places. The slightly reduced inside temperature can be effectively combated by one of the most ancient human inventions: clothes. Some of the more expensive thermostats can be programmed to different target temperatures for each time of day. Of course, this can also be done manually, but the thermostat will enforce the schedule more strictly than the average human.
This concludes my little energy efficient heating checklist. Of course, you can always think of additional ways to increase your heating efficiency. If we don’t reduce our overall energy consumption and get off fossil fuels very soon, we will probably be in serious trouble in less than 50 years. Not only will the average temperature of the Earth have risen by more than the “safe” 2 degrees Celsius, but reserves of fossil fuels will be almost depleted and renewable energy sources will simply not provide enough power to cover our needs. Thanks for bearing with me and check back soon for some tips on efficient water heating!
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