Our winters are generally cold rainy seasons, with temperatures between 0 and 8 degrees Celcius for about 6 months. How to heat our home has been the most difficult decision so far. We are lucky to have a southern exposure, for passive solar gain, and we have included a big bank of windows on that side.
In my dream world, we would harvest heat from the sun, using photovoltaic (PV) cells in our roof tiles, and solar collectors. We would sell our excess electricity to BC Hydro.
A town in Germany (Marburg) has legislated this approach. Germany is the leader in solar PV technology. It is an industry that is in active development, and not yet either effective enough nor affordable for a little homeowner. In our cloudy climate, PV technology doesn’t work. However, solar hot-water assist is feasible, and I will discuss this later in a post about plumbing.
D is keen on a masonry mass radiant wood fireplace, placed in the home’s center (i.e. not on an outside wall). It burns very hot, for a short period of time, then stores the heat in the masonry, whence it radiates out. Wood in British Columbia is a renewable resource, and quickly grows to replace the harvested timber. Much construction wood waste goes into the landfill, so perhaps we could harvest it from building sites. This type of heater is popular in Scandinavia and other European countries. D will write more about it in a future post.
My major concern is that we don’t want to be chopping and hauling wood when we’re old. D loves to chop wood, though, and so we will install this type of heater, and let the chips fall where they may when we’re too old. We have ordered the kit from www.lakeshoredesign.info. Our mason will install it.
However, we will have a back-up heating system for when I’m home alone and lazy.
An air-to-air heat exchanger (or “pump”) works like a refrigerator condenser, taking the temperature differential to heat the home in winter and cool it in the summer. It also needs a back-up furnace for when the outside temperature goes below -9 C. The exchanger sits outside, and does make a noise that can be irritating, so we are advised to keep it away from the quiet areas of the house. The cement pad it sits on must not be connected to the foundation wall, because the vibrations would increase the noise in the house. We considered a geothermal system with radiant heating in the floors, but have been convinced (mostly from this article) that radiant is not cost-effective for a well-sealed and insulated single family dwelling in our climate. The cost for a geothermal system is about 3x that of an exchanger. It is more cost-effective for multi-family developments, where the developer can recover the cost from many owners (We have heard that the strata fees in this type of development are very high, as the developer “sells” the heating system back to the owners over time). In-floor radiant heat, which is all the rage, doesn’t cool in summer, nor is it particularly cost-effective in a well-insulated home (50% more). The heat exchanger is a 96-98% efficient cost-effective source of heat and cooling.
In comparing the various heat pump brands and what kind of efficiency we will need for our home, we are offered the SEER (Seasonal Energy Efficiency Ratio) rating. According to one reviewer, this really measures the unit’s ability to cool the home in the summer heat. It’s suggested that a better comparison for its heating ability in a colder climate such as Canada’s is HSPF (Heating Season Performance Factor). A rating of 5, 6, or 7 is considered high, and some systems even rate 9. One manufacturer, at least, uses an AFUE (Annual Fuel Utilization Efficiency) rating. Hard to compare.
A Natural Resources Canada – Office of Energy Efficiency web site has a table comparing the cost of various heating systems in 7 locations across Canada. Very interesting, and supports the choice of a heat pump (exchanger.)
(The following section applies to grants available for heat exchangers, and will be of interest only to those considering installing one. It is excerpted from this website, because the official EcoEnergy web site appears to be Canadian Government propaganda. )
Conditioners
In the case of air-source heat pumps and central air conditioners, a manufacturer’s new ENERGY STAR qualified matched condenser coil (outdoor unit comprising a condenser coil, compressor and cooling fan) and indoor evaporator coil (typically located with the furnace) must have a SEER (Seasonal Energy Efficiency Ratio) of 14.5 or higher. Under no circumstances will the replacement of only one of these coils entitle the homeowner to a grant, just as components that are not certified by the manufacturer as being matched (i.e. tested together) will not be accepted.
Currently, some manufacturers match their low SEER air conditioner/air-source heat pump coil packages with one of their brushless DC motor-equipped furnaces (i.e. blowers) as a method to reduce the power consumption requirement for ENERGY STAR compliance and labelling. However, this arrangement is not accepted under the ecoENERGY Retrofit – Homes program because NRCan already provides separate grants for furnaces that have an energy-efficient brushless DC motor.
To be ENERGY STAR qualified in Canada, in addition to the minimum requirement of SEER 14.5, air-source heat pumps must also have a minimum heating seasonal performance factor (HSPF) of 7.1 for Region V, which is more reflective of the Canadian climate.
If the heat pump is only rated for Region IV, which is used in the United States, it must have a minimum (HSPF) of 8.2.
Mini-split (ductless) air-source heat pumps must have at least one head per floor, excluding the basement, to qualify for a grant.
In the case of mini-split (ductless) air conditioners that do not have at least one head per floor, excluding the basement, each head will be considered a room air conditioner and the grant amount will be reflected as such.
When having your new central air conditioner or air-source heat pump installed, ask the contractor to indicate on your invoice the manufacturer’s name (not the model name) of the condenser coil and the model numbers of both the new condenser and evaporator coils. Preferably, the Air-Conditioning and Refrigeration Institute (ARI) reference number should also be referenced on the invoice. The energy advisor will request to see this information when performing the post-retrofit evaluation of your home.
{ 1 trackback }
{ 0 comments… add one now }