In Permaculture

After looking at lists of bad building design choices, I’ve gathered together top 11 promising appropriate technologies I’ve seen in use for residential and commercial buildings. For those of you not familiar with the term, appropriate technology generally refers to technology that is small-scale, decentralized, energy-efficient, environmentally sustainable, locally controlled, and people-centered (Wikipedia).

Appropriate Technology #1: Solar Photovoltaics (PV)

Solar has never been cheaper than now. Buying a solar array is like having your own oil field, except it sits on the roof, is completely quiet and is emission-free. Investing in a solar array is like buying the next fifty years of power at today’s prices. We all know that power will only get more expensive, so why not lock in for the long-term while helping the planet at the same time? Homes built with the Passive House methodology are so efficient that they actually use PV power to provide supplementary heating.

Appropriate Technology #2: Solar Thermal

This is a low tech way of meeting the majority of your hot water needs without using any fossil fuels. The technology has been around for a long time and is solid and reliable. Check out for more details.

Appropriate Technology #3: SolarWall

Turn that liability (a hot southern wall) into a valuable asset. The SolarWall® is a Canadian technology that turns the cladding around buildings into a hot air collector. A bypass vent keeps the building cool in the summer. When you factor in the price of siding and apply it to the price of a solar wall, the cost is quite competitive and is a quick return on investment (3-6 years). In addition of being able to meet close to 50% of your heating needs, it is ultra durable and will protect your building for years to come.

Appropriate Technology #4: Solar Roof

Essentially a solar roof is a heating system that’s integrated into the roof of a building. Typically metal roofing is installed on top of a Tyvek™ building fabric with an airspace between the roof and the metal.  A dark metal material is used to absorb heat while air ducts are placed into the attic to harvest the hot air collected below the roof surface. The air is injected into the house or below the main slab and non-perforated weeping tiles to heat the floor. For regulation, a thermostat is installed under the metal roofing while a fan turns on or off based on the air temperature.

This is very similar to a solar coffin, which a friend of mine uses to keep his home warm.

Appropriate Technology #5: Standing Seam Metal Roofs

Standing Seam RoofI’m a huge fan of metal roofing. There are a ton of unique things you can do with it, such as harvest rain, collect solar hot air, and keep your home cool in the summer. If designed properly, your investment will last a lifetime. Having said this, I am only a fan of standing seam metal roofing. The inexpensive roofing is held down with metal fasteners that have neoprene washers to seal any holes made.


Appropriate Technology #6: Earth Tubes

Earth Tube

I’m infatuated with the simplicity of earth tubes. Earth tubes are plastic pipes that convey cool underground fresh air into the home. They are typically buried below the frost line where the temperature of the earth is constant. In the winter, they preheat incoming frigid winter air (lets say, from -30˚C to -10˚C), while in the summer they can keep an earth fridge cold or air condition your home.

Read about a case study where we designed a heating system for a home using a variation of the earth tube design here: Annualized Geosolar.

Appropriate Technology #7: Basement Rain Cistern

This is an element that you don’t see all that often – the only place I’ve seen it is in old homes in Saskatchewan. My grandmother’s house had a cistern that collected all the rainwater used for their garden.  It was built with cinder blocks and sealed with tar (not the greatest!). For me, basements are not typically the nicest place to live anyways so using it for rain storage seems like a great use!

Appropriate Technology #8: Composting Toilet

clivus multrum composting toilets

I’ve come across a lot of composting toilets in the last five years. The main complaint for most commercial ones is that they struggle to deal with all the liquids sent their way. If you are going to use one, I recommend setting up a piss bale for the men, or finding another urine harvesting/diverting system to reduce the liquid load (i.e. a waterless urinal).

The two composting toilets I’ve heard good things about include The Phoenix and Clivus Multrum (shown above). I’ve used both and they work well. They’re not cheap to set up, but they will last forever!

Appropriate Technology #9: Sunfrost RE-fridge

Sunfrost fridge

The Sunfrost Fridge is one of the world’s most energy-efficient refrigerators. It utilizes a very simple design: More insulation in the walls and less energy is needed to keep the fridge cool. Check them out, as they might make sense for your next off-grid project.



Appropriate Technology #10: Rayburn wood stove

rayburn stove

I was introduced to the Rayburn stove in Australia and it’s awesome! It’s a cook stove, oven and hot water heater all in one. This makes so much sense in our cold climate. They’re not cheap, and I’m not sure if they are CSA approved in Canada, but they’re definitely worth checking out.



Appropriate Technology #11: Wall Therm

wall thermI was just sent information on the Wall Therm recently and I’m pretty impressed with what I’ve seen so far. It is a fireplace with a water jacket so it can heat your living room, floors, and provide domestic hot water all at once. They cost around $6,000 and are sold on the east coast. Check them out here.



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Showing 9 comments
  • Diane Ransom

    Hi Rob, We’re building a home in Naramata, BC and plan to include a solar PV array, tied to the grid, on our standing seam metal roof (very exciting). Can you or anyone else recommend a Canadian supplier for the PV panels?
    Thanks for your continued inspiring work!

  • Jenn TR Stotland

    A great post, I had not heard of a few of these options (like the Solar Wall).

    I would like to ask what you propose be done with the extra urine diverted from the central composting unit?

  • Bob Reckhow

    Hi Rob,
    I’ve been liking this series, but I have one question about this one. Are all of these technologies “appropriate” when you consider the embodied energy, GHG emissions, and resource depletion in the materials that they are made from? Materials like steel, silicon, and plastic (and products made from them) are “cheap” only because the are products of an industrial system that is based on subsidized fossil energy, and that fails to account for resource depletion and all kinds of environmental degradation. To be truly “appropriate” in our technology choices, don’t we have to restrict ourselves to strategies like reworking and reusing things that we can salvage from what has already been made (and discarded), and learning how to be content with a lot less material stuff in exchange for a lot more time interacting with the people in our community?

    • Rob Avis

      All good points Bob. Further analysis should be done on these technologies to ensure that they meet basic laws of thermodynamics. Specifically are they going to save more than they use, is there an energy payback, are they increasing global entropy or depleting it. I think that, that sort of analysis would need to be done on a “homestead” basis to really make sense. You might have some technologies that “loose” but facilitate others that gain.

      Thanks for the comment.


      • Brady

        Another interesting problem I read about with these new technologies is the ‘rebound effect’, where for example, if I save money retrofitting my house with solar I might use the extra cash to fly to Hawaii, dumping tons of CO2 into the air, negating all positive effects. I can crank the thermostat up in the winter because I have such excellent insulation… and what do we do with that old fridge when we buy a fancy new efficient model? Into the basement for beer! Food for thought in the life cycle analysis of adding new home technologies.

        Also thought I’d add this to the tech list: combo toilet+sink, where the sink water is filtered and used to fill the cistern. Makes perfect sense!

  • Marcus

    One thing I don’t like about the composting toilet designs I’ve seen is they all end up with piles of compost in the basement. I move a lot of compost these days, and moving it out of a basement is not an appealing task. Plus what do you do if you are on a slab foundation?

    • Rob Avis

      Good call Marcus. A walkout basement works great for this. Otherwise I have seen the pheonix toilets that are up one additional storey to make moving it easier. I love it when these piles are accessible by trailer.

  • Janet Greenhalgh

    Rob, I am not sure if you are aware, but Paul and I bought 5 acres near Lumby BC. It has a well and septic installed and now I am designing our house. I want to incorporate as many of these systems as I can. If you are thinking of doing workshops on any of these, I would like to be considered as a host.


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