Sunshine can do more than power panels. Here’s how solar water heating works, with current systems and prices to help you compare.
WHY WASTE THE SUN'S IMMENSE POTENTIAL on just a tan when you can use it to heat your water? Installing solar water heaters in your home can be a cost effective way to generate hot water because, well, sunshine is free!
How Do Solar Water Heaters Work?
Solar water heating systems are made up of a combination of storage tanks and solar collectors, and you can choose from two types: active and passive. The difference between them is that active systems have circulating pumps and controls, while passive ones don’t. Passive solar heating systems are normally less expensive than active ones and can also be more reliable and longer lasting. The best choice depends on your climate, hot-water demand and installation; a passive system is not automatically the best fit for every home.
Both systems usually require a well-insulated storage tank, with an additional outlet and inlet connected to and from the collector. In a two-tank version, the solar water heater will preheat the water before it enters the conventional water heater while in a one-tank version the heater is combined with solar storage in one tank.
Solar thermal collectors heat water; the separate photovoltaic panels in the background generate electricity. Photo retained from the original RESNET article.
Types of solar collectors for residential use:
Flat-plate collector
These types of collectors are insulated weatherproof boxes with a dark absorber plate under one or more glass or plastic covers.
Integral collector-storage systems
Also called ICS or batch systems, integral collector-storage systems consist of one or more black tanks or tubes in an insulated, glazed box. Cold water first passes through the solar collector, which preheats the water. The water continues on to the conventional backup water heater, which provides a reliable source of hot water. These systems should only be used in milder climates because the outdoor pipes could freeze in severe, cold weather.
Where freezing is common, Building America guidance favors an indirect system that circulates antifreeze through a separate collector loop and transfers heat to potable water through a heat exchanger. Outdoor plumbing still needs the specified protection and maintenance.
Evacuated-tube solar collectors
Evacuated-tube solar collectors have parallel rows of transparent glass tubes. Depending on the design, an absorber and heat pipe transfer the collected heat to the water-heating loop. The vacuum helps limit heat loss. Residential examples include the Sunbank and Duda systems below.
Back-up systems are usually needed to cater for overcast days and in case of increased demand. A conventional storage water heater, a built-in electric element or a compatible tankless heater can supply backup heat. A storage tank by itself is not a backup heat source; check what the package actually includes.
Current Solar Water Heater Options and Prices
These U.S. listings were checked November 3, 2026. Prices are for the listed equipment, not a completed installation; budget separately for freight, tax, labor, permits and site-specific plumbing, mounting and controls. Capacity and climate suitability matter more than the lowest sticker price.
Sunbank SB-40G passive system: $2,999.Sunbank’s current listing includes a 40-gallon tank, 15 evacuated-tube collectors and a bracket. It collects heat without a circulation pump, reducing the number of moving parts; flat-roof or ground-mount back legs cost extra. Online ordering is available, but Sunbank recommends confirming project details and freight with the company. Its freeze-protection guidance calls for additional plumbing protection and recommends drainback or seasonal use for prolonged deep-freeze climates. Confirm lead time before ordering.
Duda SHS300 active system: from $3,625.33.Duda’s listing showed the base single-coil, 37-degree-frame configuration in stock. It combines a 300-liter (about 80-gallon) tank with 30 evacuated tubes, a pump/controller station, glycol and other basic components. The separate glycol loop allows freeze protection when correctly designed and maintained. Piping and insulation packages, alternative frames and other options add cost; freight requires a quote. The seller also posts a California Proposition 65 lead-exposure warning, so review the actual component specifications with your installer.
Rheem SolPak RS80-40BP: installer quote required.Rheem’s currently listed 80-gallon package pairs flat-plate collectors with a closed-loop heat-exchanger tank and electric backup. It is ENERGY STAR certified, providing independently listed system-performance information. The manufacturer routes buyers through its installer network and does not publish a current equipment price; older catalog prices should not be treated as today’s offer. Sensor wire and tilt-mount kits are sold separately.
Ask for a complete installed quote and an estimate based on your household’s hot-water use, shading, local weather and backup fuel cost. None of the equipment prices above establishes a payback period, and no incentive has been deducted.
A certified RESNET Home Energy Professional can help put water heating in the context of your home’s energy use. For system selection and installation, also work with a qualified solar-thermal installer who can check roof loading, local permits, water quality, freeze protection and overheating controls.
This content was originally published by the Residential Energy Services Network (RESNET) here. This content has been republished with the permission of RESNET. RESNET is the independent, national nonprofit organization that homeowners trust to improve home energy efficiency and realize substantial savings on their utility bills. RESNET’s industry-leading standards are recognized by the U.S. Department of Energy and the U.S. Environmental Protection Agency, among others.
Updated content · November 3, 2026. Original RESNET reporting: October 10, 2012; first published here in 2013. Product updates by Green Builder Media; original byline retained.
Ryan Meres is RESNET Program Director. Ryan has 10 years of experience in energy efficiency, energy policy and building energy codes and has published more than two dozen case studies, reports and resources on those topics. He spent nearly six years at the Institute for Market Transformation (IMT) where he led energy code development, adoption and compliance efforts at the city, state and national levels. Prior to joining IMT, Mr. Meres was an ICC Fellow at the U.S. Department of Energy, Building Energy Codes Program. He also worked at the Georgia Department of Community Affairs (DCA) as a Building Codes Consultant where he led the adoption and implementation of statewide energy and green building codes. Ryan successfully completed a HERS class in 2007 and served as an EarthCraft House Technical Advisor at the Southface Energy Institute, conducting insulation and air sealing inspections, and building envelope and duct leakage testing for builders. He is a LEED Accredited Professional, an ICC Certified Residential Energy Inspector/Plans Examiner and holds a Bachelor’s Degree in Architecture from the Savannah College of Art and Design.
Solar Water Heaters and How to Use the Sun's Energy
Sunshine can do more than power panels. Here’s how solar water heating works, with current systems and prices to help you compare.
WHY WASTE THE SUN'S IMMENSE POTENTIAL on just a tan when you can use it to heat your water? Installing solar water heaters in your home can be a cost effective way to generate hot water because, well, sunshine is free!
How Do Solar Water Heaters Work?
Solar water heating systems are made up of a combination of storage tanks and solar collectors, and you can choose from two types: active and passive. The difference between them is that active systems have circulating pumps and controls, while passive ones don’t. Passive solar heating systems are normally less expensive than active ones and can also be more reliable and longer lasting. The best choice depends on your climate, hot-water demand and installation; a passive system is not automatically the best fit for every home.
Both systems usually require a well-insulated storage tank, with an additional outlet and inlet connected to and from the collector. In a two-tank version, the solar water heater will preheat the water before it enters the conventional water heater while in a one-tank version the heater is combined with solar storage in one tank.
Solar thermal collectors heat water; the separate photovoltaic panels in the background generate electricity. Photo retained from the original RESNET article.
Types of solar collectors for residential use:
Flat-plate collector
These types of collectors are insulated weatherproof boxes with a dark absorber plate under one or more glass or plastic covers.
Integral collector-storage systems
Also called ICS or batch systems, integral collector-storage systems consist of one or more black tanks or tubes in an insulated, glazed box. Cold water first passes through the solar collector, which preheats the water. The water continues on to the conventional backup water heater, which provides a reliable source of hot water. These systems should only be used in milder climates because the outdoor pipes could freeze in severe, cold weather.
Where freezing is common, Building America guidance favors an indirect system that circulates antifreeze through a separate collector loop and transfers heat to potable water through a heat exchanger. Outdoor plumbing still needs the specified protection and maintenance.
Evacuated-tube solar collectors
Evacuated-tube solar collectors have parallel rows of transparent glass tubes. Depending on the design, an absorber and heat pipe transfer the collected heat to the water-heating loop. The vacuum helps limit heat loss. Residential examples include the Sunbank and Duda systems below.
Back-up systems are usually needed to cater for overcast days and in case of increased demand. A conventional storage water heater, a built-in electric element or a compatible tankless heater can supply backup heat. A storage tank by itself is not a backup heat source; check what the package actually includes.
Current Solar Water Heater Options and Prices
These U.S. listings were checked November 3, 2026. Prices are for the listed equipment, not a completed installation; budget separately for freight, tax, labor, permits and site-specific plumbing, mounting and controls. Capacity and climate suitability matter more than the lowest sticker price.
Sunbank SB-40G passive system: $2,999. Sunbank’s current listing includes a 40-gallon tank, 15 evacuated-tube collectors and a bracket. It collects heat without a circulation pump, reducing the number of moving parts; flat-roof or ground-mount back legs cost extra. Online ordering is available, but Sunbank recommends confirming project details and freight with the company. Its freeze-protection guidance calls for additional plumbing protection and recommends drainback or seasonal use for prolonged deep-freeze climates. Confirm lead time before ordering.
Duda SHS300 active system: from $3,625.33. Duda’s listing showed the base single-coil, 37-degree-frame configuration in stock. It combines a 300-liter (about 80-gallon) tank with 30 evacuated tubes, a pump/controller station, glycol and other basic components. The separate glycol loop allows freeze protection when correctly designed and maintained. Piping and insulation packages, alternative frames and other options add cost; freight requires a quote. The seller also posts a California Proposition 65 lead-exposure warning, so review the actual component specifications with your installer.
Rheem SolPak RS80-40BP: installer quote required. Rheem’s currently listed 80-gallon package pairs flat-plate collectors with a closed-loop heat-exchanger tank and electric backup. It is ENERGY STAR certified, providing independently listed system-performance information. The manufacturer routes buyers through its installer network and does not publish a current equipment price; older catalog prices should not be treated as today’s offer. Sensor wire and tilt-mount kits are sold separately.
Ask for a complete installed quote and an estimate based on your household’s hot-water use, shading, local weather and backup fuel cost. None of the equipment prices above establishes a payback period, and no incentive has been deducted.
A certified RESNET Home Energy Professional can help put water heating in the context of your home’s energy use. For system selection and installation, also work with a qualified solar-thermal installer who can check roof loading, local permits, water quality, freeze protection and overheating controls.
This content was originally published by the Residential Energy Services Network (RESNET) here. This content has been republished with the permission of RESNET. RESNET is the independent, national nonprofit organization that homeowners trust to improve home energy efficiency and realize substantial savings on their utility bills. RESNET’s industry-leading standards are recognized by the U.S. Department of Energy and the U.S. Environmental Protection Agency, among others.
Updated content · November 3, 2026. Original RESNET reporting: October 10, 2012; first published here in 2013. Product updates by Green Builder Media; original byline retained.
By Ryan Meres, RESNET Program Director
Ryan Meres is RESNET Program Director. Ryan has 10 years of experience in energy efficiency, energy policy and building energy codes and has published more than two dozen case studies, reports and resources on those topics. He spent nearly six years at the Institute for Market Transformation (IMT) where he led energy code development, adoption and compliance efforts at the city, state and national levels. Prior to joining IMT, Mr. Meres was an ICC Fellow at the U.S. Department of Energy, Building Energy Codes Program. He also worked at the Georgia Department of Community Affairs (DCA) as a Building Codes Consultant where he led the adoption and implementation of statewide energy and green building codes. Ryan successfully completed a HERS class in 2007 and served as an EarthCraft House Technical Advisor at the Southface Energy Institute, conducting insulation and air sealing inspections, and building envelope and duct leakage testing for builders. He is a LEED Accredited Professional, an ICC Certified Residential Energy Inspector/Plans Examiner and holds a Bachelor’s Degree in Architecture from the Savannah College of Art and Design.