Thanks for your comments.

Firstly solar thermal is not ideal for every situation. It depends on your energy usage and of course energy cost – and your desire to reduce your CO2 footprint and reliance on the grid.

In areas where the cold water temperature is already quite warm and ambient temperatures high (like in the desert), the amount of heat needed each day to heat water is not as great as cooler areas. That does not mean that solar is not needed, it means the the system can be almost half the size of one in say CT, as the solar radiation levels are also much higher. Furthermore, if it does not get too cold in the winter, a direct flow system, rather than closed loop (freeze protected) could be used which can reduce the overall system cost by about 20-25%.

In terms of cost reductions over time, I would expect that a 30-40% reduction in total installed cost could occur over the next 3-5 years as many more installers are trained (as they are very expensive), system components are mass produced and the industry moves from a low volume high profit model, to a large volume low profit model. That and rising energy costs will make considerable impact on payback times on the investment.

If you are installing PV and using that to heat water that is highly inefficient, and in that case have an Apricus water heater would be logical as it could greatly reduce the size of your PV install. So a combination of the two is often a good idea.

Ultimately it boils down to what your motivation is. If it is purely monetary, then true in some areas with low energy costs it may not provide a fantastic payback, but in this day and age I would encourage the US society to look beyond just payback (as Australia and Europe is now doing) and look at becoming a part of the global SOLUTION to the reliance on fossil fuels and the clear impact we are having on our environment. If you haven’t I highly recommend watch the documentary film The 11th Hour. That will provide clarity as to why installing solar, wind, using low energy light bulbs, driving a smaller car……………. are all so important.

Kind Regards,

Mick.

I would be interested to hearing Mick’s comments about the potential for economies of scale for home solar thermal systems. I live in Arizona and it simply doesn’t make much sense to use non-renewable energy to heat our water when we live in the middle of a desert. And while payback times for solar thermal are a lot better than with PV it seems to me that if we significantly ramped up production to a level that is say, 25 to 100 times greater than today, we might see some considerable reduction in system prices.

So, hypothetically speaking, if the Western Governors Association supported making home solar thermal systems mandatory and demand drastically increased what kind of price reductions would we be talking about? Are we talking 20%, 30%, 50%? Has Mick run some numbers to have an educated guess at what could be expected with an order of magnitude increase in the number of systems produced per year?

I would be extremely interested in getting an insider’s take on these questions. Hopefully you are interested as well and can get some input from him. Thanks.