Monday, 17 March 2008
Investing in Energy Saving: Solar Hot Water
Add or View Comments- Mon, 17 Mar 2008
- View More On: Technology and Sustainability
I commented on a post on the Big Green Switch today. It got me thinking. Energy saving is becoming more and more financially viable. Indeed, you could go so far as to say it's becoming a financial imperitive - either from new taxes or price rises. I'm going to have a look at the available savings from various forms of energy saving devices.
Solar Hot Water
Technology
Fundamentally simple, you expose the water to sunlight, it warms up! Variations occur in the combination of pumps and the efficiency of the energy transfer between the sunlight and the water. More advanced systems use heat-exchangers and special fluids to transfer the heat to the water. Here's a video.
Advantages
Clearly, running costs are low. The environment benefits. Hot water can be maintained in general power-cuts. Grants may also be available.
Disadvantages
Well, pretty obviously, it only works when it's sunny! This makes night-time use difficult or impossible depending on the technology. And the cold can freeze the water in basic systems. From the environmental standpoint, most of them would need to be supplemented by normal systems - especially in Northern Europe. I would argue, too that they can be a bad ambassador for home-energy-generation if they don't work well.
Does it make financial sense?
I'm going to assume spending of £170 per year on hot water. This may be a way out - anyone with good data, let me know! A high estimate for the solar hot water equipment is £5,000. This may vary, of course according to your specific situation - clearly it's cheapest for new-build houses. My calculations show that with energy prices rising at 5% per year, you will recover the full cost in 18 years. If prices rise more quickly - at 10% per year - that drops to 14 years. If you get a cheaper unit you get it installed during other renovations - it could take 10 years or less.
Conclusion
Solar hot water is only going to make more financial sense as time passes. As one part of a home-power system it will certainly play its part.
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