Solar water heating and solar space heaters explained

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You already know that solar panels can generate electricity for your home, but that’s not all that solar energy can do. There are other solar technologies that make use of the sun’s thermal energy to help heat up homes and lower one’s heating bills, including solar water heating and solar space heaters.

Solar water heating: what you need to know

If you’re looking to reduce the cost of heating water for your home or business, solar water heating (also known as solar hot water) is a great solution. With a solar water heating system, you can use the power of the sun to reduce your reliance on traditional heating sources (such as oil, electricity, and natural gas) in favor of an abundant and environmentally friendly energy source – the sun!

Solar hot water systems capture thermal energy from the sun and use it to heat water for your home. Systems can either be passive or active – while passive systems use gravity and natural circulation, active systems use pumps and controls to circulate water.

Payback periods for a solar water heating system vary depending on how you currently heat your water. For example, the payback period for a solar hot water system that replaces natural gas will be longer than one that replaces electricity or gasoline because natural gas is a comparatively less expensive fuel. If you install a solar water heating system on your roof, you can expect significant annual returns dependent on your water use and previous method of water heating. Plus, using a solar water heating system reduces your emissions and your home’s impact on the environment.

Solar water heating technology has been around since the 1970s. They generally take up less space than the average solar PV system, and many homeowners can fit both solar PV and solar water heating systems on their roof.



Solar space heaters

Solar space heaters use the energy of the sun to heat your home. While similar to solar water heating, these systems typically require more collectors (and consequently, more roof space), as well as bigger storage units to get the job done. The thermal energy is harnessed at the solar collectors and used to heat either a liquid or air, which is then circulated to dispense heat.

Like solar water heating systems, there are both passive and active solar space heaters. Passive systems work like greenhouses – the collectors gather energy, and the resulting heat is trapped and circulated naturally. Active solar space heaters use pumps and other mechanisms to circulate heat.

Solar space heaters can reduce heating costs by up to 70 percent. However, most building codes require a backup heating system, so your solar space heaters should be integrated with an existing heating system.

As with solar water heating, solar space heaters are more cost-effective if they displace an expensive heating fuel, and if you live in an area where you would use the system to heat your home year round. Like solar PV panels, solar space heaters are very durable and have an average operating life of 20 years.

Installing solar water heating and space heaters with solar panels

These are just a few of many solar technologies that can help you save money on your energy bills (isn’t the power of the sun incredible?). Not only do all of these technologies use the sun, but they also share a multitude of other attributes:

  • They help homeowners save money
  • They’re often eligible for many of the same incentives and rebates
  • The systems do the best on sunny, shade-free roofs

If you are interested in installing any of these systems in your home, we recommend having an experienced, licensed contractor do the job. Make sure to register your property on EnergySage to get quotes for a solar panel installation first, and then specify your interest in other solar technologies as well. Many of our solar installers have experience installing other solar technologies like solar water heating and solar space heaters, and it will often be more cost effective to tackle all these home improvements at once.


7 thoughts on “Solar water heating and solar space heaters explained

  1. Greg Field

    Great article. We are an Arizona solar hot water manufacturer that have been building our solar hot water systems for over 35 years, Our system after tax credits and rebates net costs for the same or less as a conventional water heater. Our payback is within 3 years typically and we use a lifetime warranty, stainless steel tank that should never have to be replaced. Our operating cost annual is definitely less than a hybrid tank. Why pay to heat water in the Arizona sun? Contact us to learn more.

  2. opera youtube

    I’ve been PV heating water for years at my camp. I have a system that harvests any energy not used for battery charging and sends it to the water heater, be it 5W or 500W. The controller has a fixed PV power point voltage. When the array goes over that set point (indicating a light load) enough energy is diverted to the water heater till the voltage drops back to the set point. This is proportional and about 97% efficient. This same system could be used as supplemental heating to a residential water tank. The energy savings and payback of a 500W to 800W PV array would be comparable to that of a Heat Pump Water Heater. With a small array, you guarantee 100% of the panels potential energy production is always utilized. That is the best payoff in solar where a lot of free energy is just wasted. These controllers are fairly simple to build.

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