Passive Design, Active Results

We are slowly learning that we have the knowledge and technology to eliminate a lot of today’s conventional home energy use. The latest example is a passive solar home built in Innisfil. The outstanding feature is that it is built without the need for a conventional furnace. The south facing home is very highly insulated, sealed and uses passive solar gain. It’s no surprise that the builder and owner formerly worked with the Kortwright Centre for Conservation.

I first wrote about passive solar and net-zero energy construction a few years ago so it’s encouraging to know that the concept is finally attracting wider practical application and real world experience under our local conditions. Importantly, municipal authorities are learning to recognize this certification standard.

We’re able to learn about some of the technical details from a recent news article at Simcoe.com (Home builder lives without furnace in passive house, July 13, 2017). The home’s ‘raft’ foundation has a styrofoam base below concrete and the walls are “double stud” allowing for an R65 insulation factor. Notably, the owner says they have “come up with a wall [insulation] system just as efficient without adding significant cost.” Certainly the budgeted cost of ducting and furnace could be applied instead to this use.

An energy recovery ventilation (EVR) unit runs continuously to ensure a proper air circulation and stable temperature within the airtight building envelope. Surprisingly, energy-efficient windows came from Ireland. The article didn’t indicate what distinguished them from so many possible local window suppliers. Solar panels are being added to the home as well.

This type of approach continues to be a ‘pay now or pay later’ proposition. The builder suggests it could be offered as a “luxury option” in subdivisions with a pay-back over 20 years. Otherwise, potential home-buyers could just opt for conventional construction and take a chance with future energy prices or ‘move up’ later when energy efficient techniques become more widely adopted. Passive solar design and ‘net zero’ energy technology makes even more sense for multi-unit construction where the benefits are likely to be more easily achieved.

There is another option. Builders could consider a better trade-off between home size and efficiency. I walked through a builder’s ‘luxury’ model home recently out of curiosity. My wife remarked, “I could be happy with half of this house!” to which another couple immediately responded, “Great! I’ll buy the other half!” Maybe an enterprising builder can recognize an opportunity to make ‘less’ equal ‘more’.

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