The other day I showed you Mike’s Micro House which he has been building for under $3,000.

Mike is also quite an inventor and is interested in solar and wind energy. He has created a simple hot water heater that I think would be useful for a tiny house or a large home. I asked Mike to share the details on how he creates his solar hot water heater.

Solar water heater. Sun during the day preheats the water in a 30 gallon water tank, prior to it being sent into the on demand water heater inside the house. This solar heater has preheated the water up to over 100F more than once when the outdoor temp was in the 30F range.

This simple setup works great, and is pretty much maintenance free. Just keep the glass clean, and you are good to go. If it starts to warm the water to hot during the summer months, just cover a portion of the solar window, to lower the sunlight bombardment into the solar chamber.

The solar water heater is simply a standard water heater (preferably one that was electric not gas powered).

Here’s what you do:

1. Peel off the outer sheetmetal skin of the water heater, and cut off the foam insulation in order to get to the internal steel tank.
2. Remove the electric heating element if needed and replace with a simple pipe plug fitting if the original element was bad, causing a leak.. Otherwise do nothing but remove all the electrical wiring to the element and the thermostat controls.
3. Verify that the overtemp/pressure valve operates and looks to be in good condition, otherwise replace it, so you have a safety feature if the pressure were to build up to high from the heated water.
4. Paint the water tank, “Flat Black” in order to help it absorb more of the sun’s energy.
5. Build an insulated enclosure that the water tank can fit into, with a window on top at roughly a 45degree angle.
6. Place the tank in the enclosure so that the southern sun exposure will shine directly onto the water tank inside.
7. Plumb the cold water going to your existing home’s water heater to the input of the solar water heater, and the output of the solar water heater to the original cold water input of the original home water heater.

Now when the sun preheats the water in the solar water heater, it will be feed into your home’s existing water heater as hot water, therefore your now backup water heater should not work nearly as hard to provide hot water for your home.

To view more of Mikes inventions check out his flickr site here.

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