Heating and low temperature performance

We finally had the little Thermolec 2kW heating element installed in the HRV intake last week, just in time for a cold snap. This element is a bit like a toaster and heats the air coming into the HRV manifold that distributes heat around the house. It is controlled via a thermostat, which is downstairs and not too far away from the kitchen so we are aware that it’s likely to be a bit warmer there than elsewhere, so we keep it at 20ºC, knowing that this is likely to mean 18ºC on average around the rest of the house.

All the other heat comes from passive solar, i.e. the south-side windows, but it’s been quite dull recently, so that has not been such a big factor. In addition we’ve been having further problems with the Motura sliding door. We already had to have it taken off and some new sealing rubber put on, but it’s still not tight. This was not apparent in the recent blower-door tests, we think, because when you pressurize the air inside the house, the sliding door would have been pushed outwards, against the seals. However, at other times, this is not the case, and the higher we have the HRV settings the looser it gets. Compared to most houses, it’s not at all bad, but there is still an appreciable draft around the edges of the sliding door. We have contacted the supplier and await some advice. We might just push some of the left-over rubber gasket from the CLT construction into the edges and tape them up, just for the winter.

We are recording temperature levels a project at Algonquin College, but that data won’t be available until it’s downloaded from the recorders. In the meantime, we are just keeping an eye on performance using simple thermometers, particularly when it’s cold outside. And last night, it was very cold outside. When we got up, the external thermometer was reading -15ºC, so it could have been even colder during the night, and the winds have been fierce here, so the effective temperature would have been around -25ºC.  When we got up the temperature inside was 14ºC upstairs and 16ºC downstairs. With some sunlight in the morning and a few hours of an additional 1kW heater, this was soon up to 19ºC downstairs and 18ºC upstairs, and it has pretty much stayed that way since, as the winds blow around the house. This is pretty good. But we shouldn’t need the additional heater, and until we resolve the problem with the Motura door, one way or another, we will not be able to get the more consistently warm temperature levels we would like. It’s certainly not cold – it’s very comfortable – but the house is not yet operating at its optimum.