Solar Hot Water Heating

95% of  Hot Water demand for a residential house can be supplied by thermal solar systems.

In America we are behind the “power curve” and need to build decentralized new systems, in Mexico and other countries you see solar hot water heating everywhere.  Even the Romans used it to heat pools by painting the bottoms black.  If we used solar water heating on 1% of electic homes, we would not need to build new power plants–we would reduce the demand by 1/3.  30% of an electric house is used by the electric water heater, therefore a solar hot water system can reduce electric bill by 30% and save tons of CO2.  Solar Hot Water heating systems usually pay for them selves in 6-8 years.

Terms of Systems

Active- Uses Pump

Pasive- No Pump

Direct- Solar Loop uses Potable Water

Indirect- Solar Loop uses another fluid and Heat Exchanger

Types of Systems

Open Loop

  • – good for Tropical Climates, no freezing
  • has potential to make steam and burn out collector
  • Mineral deposits/ hard water= needs maintanence

P. Glycol Indirect

  • No freezing due to Glycol (P. Glycol is food safe and non toxic)
  • heat exchanger
  • could make steam inside tank, includes expansion tank

Drain Back

  • won’t get too hot
  • Distilled Water
  • Protection based on gravity
  • no hard water issues
  • fits in with most rebate programs

When looking for a Solar Hot Water system make sure it is SRCC, Solar Rating and Certification Corporation, to qualify for any rebate or incentive. Most of the tax incentives and rebates can be found at

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