How to turn your metal roof into a solar collector?

I have been at a workshop with Prof. Tang Lee (professor at the the University of Calgary, a AAA architect and solar technology specialist) at the “Green Building” conference in Kimberly and learned a lot about how easy and simple it is to collect and use/store solar energy.


The most important experience and lesson Mr. Lee shared with us was this:  Don’t strive for 100% results, it requires too much money and effort. Be happy with 70-80%, it achieves what you want for a fraction of the cost and work.  This is the “sweet spot” if you will.


Example:  Mr Lee created the most optimized house with solar panels in 1975 which took them an enormous effort to calculate and build. After the fact, he realized that he could have easily achieved 70-80% of the energy with a fraction of the effort and cost. Meaning, to get 100% of the possible solar energy in relation to the cost it made no sense. The cost and effort in relation to get only 70-80% of the possible solar energy makes sense and will pay for itself.


With this lesson in mind, Prof Tang Lee states that a metal roof is the simplest, easiest and most practical way to collect and use/store solar energy.


The only modification when installing a metal roof is to add vertical strapping to create an additional airspace between the sheeting and the metal roof so the heated air can travel to the ridge. Below and along the ridge there will be a framed and insulated box to trap the hot air. Once the hot air reaches a certain temperature, a thermostat will turn on a small blower to pump the hot air into an insulated cabinet housing an un-insulated hot water tank.  This preheats the water (about 30°C to 50°C) before it gets into the hot water boiler. This alone will save about 80% of the hot water heating costs.


In the winter time, the hot air can additionally be used to heat the concrete slab by simply pumping the hot air in a grid of 2 feet centered non porous weeping tiles to heat up the ground and concrete.
This is a very simple, easy to install and cheap investment which will save heating costs on an ongoing basis.


Thanks again to Prof. Tang Lee for sharing and helping to create a smaller ecological footprint and to save money.


We at are supporting this idea and will try to implement the simple technology into our houses.