photo by Tambako The Jaguar
In the last few years solar panels have been increasingly popular. The vision of producing your own electrical power and reducing use of fossil fuels is alluring. Less attention is given these days to solar thermal panels for hot water.
Hot water in the seventies and eighties
Back in the seventies all the solar roof panel talk was about the kind that heat water. People were capturing the heat of the sun for faucets, showers, laundry, dishwashers (collectively known as “domestic hot water”), and even their swimming pools. Tax credits were available and solar water panels were all the rage.
In the eighties the tax credits were removed, the focus on ecological building faded, and little was heard anymore about solar energy for houses.
All the while clever folks were making improvements to solar electrical, or photovoltaic, panels. This technology was first used for satellites and spacecraft and later developed for life on Earth. The price was low enough by the nineties for household use to become more widespread.
Now when people here the term “solar panel” they almost always think of photovoltaic (PV) panels. However, solar thermal panels have seen improvements too. And each has their purpose.
photo by Oregon Department of Transportation —PV panels
Solar PV panels
Solar PV systems can be used for an off-the-grid home, typically out in the country far from city utilities. In town your home could be drawing from or supplying the electrical grid depending on the time of day. Once a year you get a bill for the amount of power you used but didn’t produce yourself, if any.
Electricity produced by your solar panels feeds directly into your home’s wiring and can be used for anything needing electricity.
photo by UK in Italy —Thermal panels with built-in tank
Solar thermal panels
Solar thermal systems produce heated water come in many types:
- batch (heated in the tank)
- flat panel (needs storage tank)
- integral storage (doesn’t need a tank)
- passive (no pump)
- active (with pump)
- direct (water in panel feeds into domestic hot water)
- indirect (water in panel heats pipes carrying domestic hot water)
- evaporated tubes
The most common type is a flat panel and looks similar to a PV panel.
Besides providing most of your hot water needs solar thermal systems can provide heating for your rooms. Again, there are several approaches. A good fit for a solar system is low temperature underfloor radiant heating.
How to get started
If you want to make your own electricity or hot water there are more options today than ever. To find out what can be done at your home call a local solar installation company.
They are usually more than happy to come out, check your roof’s solar access, and tell you what works best for you.
