DORCHESTER, ONTARIO — I enjoyed reading Dave Yates’ article on his solar installation in Contractor magazine (May, p. 40).

The solar thermal industry, as you know, has been around for a number of years, but it is just recently gaining considerable momentum given its favorable cost profile when compared to other renewable energy technologies. With that said, I think it is important that when authors quote installed costs for solar thermal systems that they do so in a fair and reflective manner.

I agree that a Viessmann evacuated tube system would cost $10,000 (Thermomax would be higher, Apricus about the same). But the North American market is approximately 85%-95% flat plate and most flat plate systems would cost between $5,500 and $6,500 to install. Unless you are in northern climates and integrate a solar thermal system into a hydronic or geothermal heating application, it makes little sense to install an evacuated tube system. Evacuated tube systems are more efficient on a per unit of area basis in the winter months — but — on a cost per unit of energy produced basis, they fall down quickly vs. flat plate systems (according to studies at North Carolina State University Solar Center and Queen’s University Solar Calorimetry Lab)

My last point is that it is only fair to readers to point to other solar thermal incentive programs at the state and local utility level (Database of State Incentives for Renewables & Efficiency, www.dsireusa.org) since, chances are, there are significantly greater incentives available over and above the Federal program. In other words, chances are that the installed costs are much lower than what is suggested in the article.

Great article and certainly food for thought.

Please see our website at www.enerworks.com for more information on flat plate solar thermal appliances.

Ken Arnold, CEO