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What Is a Solar Hot Water Heater? (2024 Guide)

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Author Icon By Tamara Jude Updated 12/19/2023

A solar water heater is an eco-friendly and cost-effective way to meet your hot water needs. They can help you reduce your carbon footprint and lower your utility bills. In this guide, we use our expertise on the best solar companies to break down solar water heaters and prepare you to make an informed decision for a more efficient home.

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What Do Solar Hot Water Heaters Do?

Solar water heaters use solar power to produce hot water. These water heaters can supplement or replace traditional water heaters, which reduces your reliance on fossil fuels. This reduction lowers your monthly energy bills while providing hot water for bathing, laundry, cooking, and radiant space heating.


Types of Solar Water Heaters

There are two types of solar water heaters: active and passive. We break down each solar water heater system below.

Active Solar Water Heating Systems

Active solar water heating systems come in direct or indirect circulating systems. Read over each active system below.

  • Direct circulation systems: These systems use pumps to circulate household water through the collectors and into the home. A direct circulation system is ideal for climates that rarely experience freezing temperatures.
  • Indirect circulation systems: This system uses pumps to circulate a non-freezing heat-transfer fluid, such as antifreeze, through the collectors and a heat exchanger. This process heats the water that then flows throughout your home’s plumbing. Indirect circulation systems are better for cold climates prone to freezing temperatures.

Passive Solar Water Heating Systems

Passive solar water heating systems store water for cold and cloudy days. Passive systems are more dependable, cost less, and last longer than active ones. However, they can run out of heat after a long cold spell.

There are two types of passive solar water heating systems, which we explain below.

  • Integral collector-storage passive systems: These systems work best in areas where temperatures rarely fall below freezing. We recommend this passive system for households with significant daytime and evening hot water needs.
  • Thermosyphon systems: With these systems, water flows through and warm water rises as cold water sinks. The collector, located below the storage tank, helps the warm water rise into the tank. These systems are reliable, but many contractors hesitate to install them as they pose challenges to roofs due to their heavy storage tanks.

Solar Hot Water Heater Cost

The cost of a solar water heater varies depending on the type of system, tank size, location, and other factors. According to our research, solar water heater installation costs between $3,000 and $9,000.* However, after federal tax credits and rebates, a solar heating system could end up costing around $1,500–$6,600, or 26%–50% less than the sticker price. We suggest contacting a professional solar installation company to learn what the project will cost you.

*Cost figures are based on averages from multiple sources, including the U.S. Energy Department and EnergySage.


Are Solar Water Heaters Worth It?

Solar water heaters provide many benefits, from significant cost savings to a reduction in your carbon footprint. Below, we explore why solar water heaters are worth it.

  • Cost savings: Similar to solar panels, solar water heaters help your home operate on solar energy, substantially reducing your energy costs.
  • Eco-friendliness: Embracing a solar water heating system advances environmental sustainability and clean energy. Using renewable energy reduces greenhouse gas emissions and reduces your reliance on nonrenewable energy sources.
  • Energy efficiency: Solar thermal systems maximize energy efficiency. Modern solar collectors are highly efficient, ensuring optimal performance and effective yearly water heating.
  • Reliability: Manufacturers design solar water heaters to be reliable and durable, often built to withstand harsh weather conditions. With proper installation and regular maintenance, these systems can provide reliable hot water for up to 20 years. That’s roughly five to 10 years longer than conventional water heaters.
  • Return on investment (ROI): While the initial investment in a solar water heater is hefty, it provides long-term returns. With reduced energy bills and government incentives available in many regions, the system pays for itself over time. Most solar water heaters have a payback period of roughly two years.
  • Versatility: You can integrate solar water heaters into existing homes and new construction projects. They can work in tandem with conventional water heaters, or they can function as stand-alone systems. Additionally, various system configurations are available to suit different climates and household sizes, making solar hot water heaters a versatile and adaptable choice.

Hidden Costs and Downsides of Solar Water Heaters

While a solar water heater offers numerous benefits, it’s crucial to understand its potential challenges and hidden costs to ensure it’s a sound investment for you.

  • Backup heating system: Solar water heaters may require a backup heating system, especially during prolonged periods of low sunlight or high hot water demand. A technician may suggest an extra gas or electric water heater backup system to ensure a continuous hot water supply. This addition increases the overall installation cost and your energy consumption.
  • Maintenance: Solar water heaters are generally low maintenance, but inspections and maintenance every three to five years are necessary to ensure optimal performance. Components such as pumps, valves, and storage tanks may require occasional repairs or replacements over the system’s life span.
  • Sunlight availability: Solar water heater efficiency relies heavily on sufficient sunlight exposure. The system’s performance may be compromised if your property is surrounded by shading from trees or buildings.
  • Up-front cost: While long-term savings can be significant, a solar water heater’s initial investment is higher than a conventional water heater. We recommend assessing your budget and weighing it against the potential long-term benefits.

Our Conclusion

As long as you have the right setup and budget for a solar water heater, it can be an excellent way to save money in the long run and make your home more energy efficient. Like other water heaters, a solar water heating system isn’t the most DIY-friendly project and requires professional installation by someone with much expertise. Because of this challenge, we recommend hiring a solar company to install your solar water heater.

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FAQ About Solar Hot Water Heaters

How hot can water get with a solar heater?

Most solar water heaters can heat the water up to 180–200 degrees Fahrenheit, just like a conventional water heater.

Can I use a solar water heating system in place of my existing traditional gas or electric hot water system?

Yes, solar water heating systems can either supplement or replace your existing hot water system.

Do solar water heaters work at night?

Most solar water heater storage tanks store the hot water generated during the daytime so that you can use it at night. In addition, most active solar water heating systems include backup heating elements to ensure hot water is available when there is no sunlight.

Is it safe to drink water from solar hot water systems?

Solar hot water systems heat water, but they don’t purify it. As long as the water going into the system is potable, safe-to-drink water, the water coming out of the system will also be safe to drink.

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