Passive homes and the love-hate relationship with passive solar energy

Passive solar energy - Harvest it or block it out - Which is better?

Greg Clarahan of LiteZone Glass told us in our story about his amazing super windows (above video) that can reach insulation values of R22 that he "has a different idea."

That idea is to use R17 windows in a net-zero or passive home and stop heat transfer in and out to create a stable environment in a home that requires very little energy to heat and cool in the first place.

This runs contrary to the foundational passive house idea that you build south-facing homes with windows that help harvest passive solar energy in winter to provide significant amounts of passive heating energy.

Mark from Moncton, New Brunswick wrote to us and he asks the good question about what we said in that video.

At 7:07 in this episode you say “in too many cases passive houses become ovens in the summer and struggle to harvest passive solar energy in the winter”.

Isn’t the whole idea of a passive house to overcome these things?

I’m confused. Would you be able to address this in a future episode?

Passive solar energy is a widely subscribed to principle used in building super-efficient homes. Indeed we have done dozens of stories about passive homes, net-zero homes, straw bale net-zero homes, Earthship passive homes, and many more.

But with the advent of R17 glass units, Greg Clarahan brings a powerful nuance to this discussion. Now you can prevent heat from coming in in both summer and winter very effectively.

One of the?first stories we did on a net-zero home featured a dramatic home design with an entire wall of windows (triple-paned) facing south. They also built an overhang over the windows that was designed to prevent any direct sunlight from hitting the windows in the summer to prevent overheating. In winter the sun streams through the windows hitting a concrete floor which slowly stores the heat of the day and then slowly releases it overnight. (also see “The power of passive solar and thermal mass ”?a story we did at this same home.)

There are many homes that take great pains to do this very well indeed. But we have also heard of many homes that were not designed as well that have overheating problems in summer.

Here’s our big learning after covering efficiency innovation in buildings for a decade: Nobody ever lands on the ultimate answer and there is always something more to learn and every innovative builder we've talked to evolves their models every year.

For example, the foundation of building net-zero and passive homes is to build them with exceptionally high levels of insulation.?Peter Darlington of Calgary follows this philosophy and renovated his own old home to net-zero. ?The cost was $100k.?

The idea is to reduce the amount of energy you require as much as possible. But then we found a young engineer, Jacob Komar, who said there is another way. His idea is to spend more money on energy production in the form of geoexchange and less on insulation. See?222. Geothermal Revival – Getting to net-zero the easy way

Which is the “right way?” Our pragmatic answer is both. Our goal is to continue the journey of optimizing super-efficient buildings and to do this we must always be open to new ideas and the evolution of ideas.

Then there are building champions that are laser-focused on building the most affordable super-efficient homes. Resa Nasseri and his company Landmark Homes in Alberta is one of the best examples we've found. They produced the most affordable net-zero homes we have seen. They do this through modeling and the laser-focused optimization of the cost of components. Their wall system is simple: 2x6 with EPS on the outside.

Greg Clarahan’s LiteZone super-efficient windows are a radical departure that has the potential to disrupt our thinking and the designs of super-efficient home builders. Let’s face it, we marvel at triple-paned windows and have championed them for years, especially in net-zero and passive home circles. But the fact is the good ones are about R8. Clarahan says his best-selling LiteZone glass unit is a 4-film version with 2 panes of glass and is about 4.5 inches thick. This glass unit clocks in at R17.?What will this mean to net-zero and passive homes? Well, your guess is as good as ours, but we are pretty sure this has the potential to disrupt.?

Sometimes it's hard to get at the nuances in our podcasts which must be 4-minutes to run on CKUA Radio. Not complaining, just saying. Personally, I am building a net-zero home right now. It will have low-carbon R61 foundation walls made out of EPS and steel. The home walls will be double studded 16-inch walls. So I still have great confidence in the original passive home concept of building super efficiently.?

Here's to all the heroes of innovation in this space, many of which we have had the pleasure of meeting and sharing their ideas over the last decade and may the journey and the innovation continue.