It’s time to talk about the systems in our compact Frontenac House. We’re as proud of this rural home’s systems as we are its airtight and well insulated envelope.
Besides a small propane tank used for the freestanding fireplace, only three or four times bigger than the kind linked to an outdoor barbecue, the whole house is run entirely on electricity!
The home’s systems are fairly standard – for Solares projects, that is. An electric heat pump mini-split is used for air conditioning and heating the building, and an Energy Recovery Ventilator unit moves fresh air throughout the house through separate ductwork. The house conserves energy by using separate ducts for the heat pump and for the ERV.
For fresh air ventilation, it’s best to remember that a little goes a long way. Sure, you can just open a window if your house gets stuffy, but conditioning huge amounts of fresh air takes a lot of energy. For example, cracking a window in the winter means your heating system has to work overtime: All the inside air it worked so hard to condition goes – quite literally – right out the window, and now it has to start from scratch to heat new, cold, and unconditioned air. Not the best for your home’s energy efficiency – or for your heating bills.
With an ERV, small amounts of fresh air is introduced in a controlled way, by the ERV unit. The ERV also expels stale indoor air. But first, it retains the outgoing air’s heat and humidity levels, and transfers it to the new, incoming fresh air. That way, the air is still fresh, but the temperature and humidity levels stay comfortable and constant inside – no more overworking your systems! As Tom always says, “seal it tight and ventilate it right”, and giving your heating systems a well-earned rest comes as an added bonus of following his mantra!
Because the ERV doesn’t need to move a ton of fresh air throughout the house, the ERV’s ductwork can be small – only 4 inches round to be exact. However, the heat pump needs to be heating, cooling, and conditioning air in large volumes, which makes larger ducts the smarter choice for the mini-split. Though you can combine both functions (the ERV and the heat pump mini-split) into the same ductwork, the ERV has to work much harder to push the small amount of fresh air it collects through large ducts. With separate, smaller ducts, the ERV’s fan doesn’t have to work overtime.
We’ve also equipped this home with other clever ways to use and re-use heat, like a condensing dryer and a heat-pump hot water tank.
The condensing dryer looks like a conventional tumble clothes dryer. However, instead of venting the hot air and moisture, as a conventional dryer does, it vents the heat into the house, and the moisture goes down the drain. Not only does this recover heat from the dryer to use for other purposes, but it also doesn’t add any holes to your envelope, because the air doesn’t escape from the house through a vent.
The heat-pump hot water tank is another clever energy-recycler. The heat pump heats the water in the water tank by taking heat out of the air, just like the mini-split’s condenser/compressor placed outside. We’ve placed the heat-pump water tank in the home’s laundry/mechanical room, so now every time the couple does laundry, they’ll also be heating water, by allowing the heat-pump water tank some extra hot air! Another benefit to this heat-pump sucking up hot air is that it keeps the house’s interior cool in the summer.
On the house’s sleek exterior, a solar array sits unobtrusively on the flat roof.
The array was installed as a separate building phase, after construction was finished, and is part of Ontario’s MicroFIT Program, collecting solar energy and feeding it back into the grid for a profit. Though technically, it’s impossible to say whether the solar power collected is the same energy the house uses, the house actually collects more energy than it uses, which is an exciting feat!