There have been a few questions about heating systems and heat distribution recently. I asked Canada’s green building grandfather if I could publish a paper that he wrote about how heat gets distributed in an advanced home. For your reading pleasure, written by Rob Dumont of Saskatchewan Conservation House fame:

Space Heat Distribution - Energy Answers by Rob Dumont

A Scan Andersen 10 woodstove, installed in the MCNZH.

People commenting on a recent national CBC article about Edmonton’s NetZero Energy houses spent a lot of effort criticizing the fact that the Mill Creek NetZero Home (MCNZH) has a wood burning stove. Besides proving beyond a doubt that the only thing worse than an ignoramus is an anonymous ignoramus, the comments taught me a bit about what messages to send in a sound bite culture such as ours.

For the record, the MCNZH will consume net zero annual energy without taking the wood burning stove into account. Even if we never burn a fire, the house will consume about 8000 kWh of electricity per year and its PV modules will produce about 8000 kWh per year.

Our Scan Andersen 10 wood stove has been installed, and we really love the quality of warmth that it radiates. Our source of wood will be construction waste from renovation projects in the neighbourhood. If we heated only with wood, here’s how big a pile the MCNZH would use annually:

A pile of tightly packed construction waste this size will heat the MCNZH for one year.

The pile is 1500 litres in volume, and it represents two thirds of a cord of wood (the cord would be 30% bigger because of the extra spaces between split firewood). We’ll be able to burn the wood very cleanly, because the stove is surrounded by the thermal mass of the concrete floors and a brick mass wall that will installed behind it. A quick clean hot fire will radiate heat into the mass, which will slowly release it into the house for hours afterwards.

Because the heat from the fire will be displacing electric heat from our baseboard heaters, we will in effect be converting construction waste into electricity. The wood stove should make the MCNZH a net electricity exporter of 2000-2500 kWh per year. Because the construction waste wood would have rotted in a landfill anyway, I consider it to be completely carbon neutral. That’s good for the environment, and wood heat provides a good deal of the resiliency that the times ahead will demand.

(cross posted at raisingspaces.com)

Here is a diagram from the IBC boiler installation manual showing the specifications for the venting.

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MCZNH Solar Awnings (summer and winter positions)

The Mill Creek NetZero Home (MCNZH) will have a ground-breaking solar awning installed on its south face (introduced in Solar Awning Part 1). Essentially, it's a movable awning made out of photovoltaic (PV) modules. It will serve two functions: to shade the south windows in the summer and fall, and to tilt the modules so that they are always at an optimum angle to the sun. An analysis of the solar awning's net energy benefit follows.  read more... »