Passive solar heat ideal
Written by Econ’s Dalit Holzman and originally published by North Shore News September 2013
Over the last few weeks, it seems like the days have been spent less in shorts and more in woollen long-johns, the children scurrying off to school sack-packed with muddy-buddies and rain boots. Ahh yes, truly summer has officially waned and autumn is here. Time to bring out the knitting, the hot water bottles, the novel abandoned back in June. Finding warmth is now at the top of my biological imperatives list. In this installment, I’ll shed a bit of (vitamin D filled) light on some home-heating options (other than layers of wool sweaters) readily available to us here in the Pacific Northwest.
Passive solar heating is, by far, the most ideal and most efficient option available. Rather than relying on solar panels (used in active solar, or photovoltaic, electric generation), passive solar is achieved through the direct heating of thermal masses within the home. The warmth absorbed by these masses while the sun is shining is then radiated out as the ambient air temperature cools (and the sun goes down). (Anyone who has sat on the sandstone beaches of our area after sunset can attest to this effect.) Whether it’s the floor, the walls, or a giant decorative black boulder that sits in the centre of your living room floor, as long as the envelope and windows of a home are robust enough (recall the Passive House principals I described 2 months ago: double wall thicknesses, triple-pane windows), then the warmth will be absorbed and re-radiated as described. While there is no downside to this carbon-neutral and zero-cost heating method, relying on it for your home’s heat does require specific building positioning to the sun and the incorporation of the previously mentioned robustness. I encourage anyone seriously considering passive heating to familiarize themselves more broadly with Passive House design principles. (Please do not hesitate to email me directly for more.)
Geothermal heating is another efficient option for some in our area. The process operates from the heat differential that exists between the temperature of the air and the temperature of the land just below the surface. With the aid of an electrically powered ground source heat pump, the energy is extracted and the home is heated (or even cooled in the summer months). The downside of this technology is that it relies on long runs of pipe. People living rurally may not have a problem with running 1500+ feet of pipe 4 feet deep, while urban counterparts might find the four 300 foot deep holes necessary (due to lot size constraints) rather cost prohibitive.
Radiant heating is experienced via radiators (hot water or electric), masonry stoves (in Europe mostly), and, most popularly these days, through electric or hydroponic in-floor systems. If radiant heating is incorporated within a passive solar or geothermal system, or more holistically within a Passive House model, the amount of power it requires can be greatly reduced.
Keeping its inhabitants warm and dry is every home’s chief objective. Home design focused from its outset on achieving warmth (or cool depending on the season) has a better chance at long-term success and sustainability than design that treats it as an afterthought. The cost of heating its interior does not have to be the greatest (and most wasteful) operating expense of owning a home.
If you’re keen to know more about what makes Passive Houses so energy efficient, how they can literally be heated with candles, I encourage you to check out the Passive House North 2013 Conference going on this Friday and Saturday (the 27th and 28th) at the Westin Bayshore in Vancouver. For more check out http://www.passivehouse.ca/conference-2013.