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PLUMBING TOPICS
WATER HEATERS
ALTERNATIVE HOT WATER SOURCES
  High Efficiency Water Heaters
  Indirect-fired Water Heaters
  Instantaneous Water Heaters
  Multiple water heaters in parallel
  Multiple water heaters in series
  Range Boiler Water Heaters
  Side Arm Coil Water Heaters
  Solar Water Heaters
  Tankless Coil for Hot Water
ANTI SCALD VALVES
CHIMNEY INSPECTION DIAGNOSIS REPAIR
Clogged Piping & Hot Water Flow
ELECTRIC WATER HEATERS
GAS FIRED WATER HEATERS
  DRAFT HOODS - gas fired
  Gas BTUH & Cubic Feet
  GAS PIPING, VALVES, CONTROLS
  SPILL SWITCHES - Flue Gas Detection
HOT WATER IMPROVEMENTS
HOT WATER QUANTITY IMPROVEMENT
  Anti-Scald Valves & Hot Water Quantity
  Clogged Piping & Hot Water Flow
  Extra Tanks to Increase Hot Water
  Insulate Hot Water Piping
  Insulate Hot Water Tank?
  Larger Diameter Water Supply Piping
  Tankless Coil Hot Water Increase
  Temperature of Hot Water is Too Low
INDIRECT FIRED WATER HEATERS
ODORS IN WATER
OIL FIRED WATER HEATERS
  DRAFT REGULATORS - barometric dampers
  OIL BURNERS
  OIL BURNER NOISE SMOKE ODORS
  OIL PIPING
  OIL TANKS
MIXING VALVES
RANGE BOILERS
RELIEF VALVES - TP Valves
SOLAR HOT WATER HEATERS
TANKLESS COILS
  Clogged Piping / Tankless Coil & Hot Water Flow
  Mixing Valves
  Tankless Coil Leaks
  Tankless Coil Hot Water Increase
WATER HEATER PROPERTIES
  Electric, Gas, Oil Water Heater Efficiency
  Water Heater Life Expectancy Comparisons
  Water Heater Operating Cost Comparisons
  Water Heater Purchase & Maintenance Costs
  Water Heater Water Quantity Comparisons
  Water Heater Recovery Speed Comparisons
  Water Heater Safety Comparisons
More Information

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Guide to the Basics of Solar Hot Water Heating Systems
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Our site offers impartial, unbiased advice without conflicts of interest. We will block advertisements which we discover or readers inform us are associated with bad business practices, false-advertising, or junk science. Our contact info is at inspect-ny.com/appointment.htm.

Here we discuss the basic components of solar hot water heating systems used to heat water for washing and bathing.

Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution. © Copyright 2008 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use the links at page left to navigate this document or to go to Other Website Topics. Green links at left show where you are in our document & website.

How to Hook Up & Use Solar Water Heating Systems to Provide Domestic Hot Water

Solar water heaters use renewable energy - sunlight - collected in outdoor rooftop or ground-mounted solar collectors to heat water which is circulated by a pump between a hot water storage tank and the panels.

The upper end of a simple solar water heater collector is shown in our photo at left. Look closely and behind the corrugated plastic surface, at the top you can see the horizontal black tubing that moves water through the top end of this collector.

Solar water heaters have been in use for decades, with popular use at remote cottages or off-the-grid buildings and are likely to see increasing use in much of the world as energy costs continue to climb.

What are the Components of a Solar Hot Water Heating System?

The schematic at left (Lennox Industries) explains a typical solar water heater hookup and shows the basic parts of a solar hot water system. Here are the key parts of solar hot water heating: (Sketch at below left courtesy of Accu-Spect. Sketch at page top courtesy of Lennox Industries)

One or more solar collectors are located where they will receive an appropriate (or maximum) amount of sunlight. In our photo below you can see a simple solar collector hanging at the Don Pedro Ferreteria hardware store in San Miguel de Allende, Mexico.
Heat exchanger: The solar hot water collectors are connected by a loop of piping to a heat exchanger unit located inside of a hot water storage tank located in the building. In other words, the building's domestic water supply to be heated is not itself circulated through the solar collector but rather it is heated inside the water tank by a heat exchanger which itself contains a liquid (containing an anti-freeze in northern climates) which circulates in the solar collectors and inside the heat exchanger.
A hot water storage tank contains domestic hot water heated by the heat exchanger; the tank is supplied with incoming cold water and provides outgoing hot water to the building's plumbing fixtures. In our photo below you can see a simple solar water heater tank at the Don Pedro Ferreteria hardware store in San Miguel de Allende, Mexico. In areas where there is plenty of sunlight and water usage is more modest, a simple collector, pump, controls, and small water tank such as the one we show below are often adequate.

Temperature sensors mounted at the water storage tank and also at the solar collectors monitor water temperatures and communicate with a solar controller module.
The solar controller module determines when it is appropriate to circulate water from the hot water tank through the solar collectors, preventing water circulation when it would cool rather than warm the hot water.
A circulator pump is controlled by the solar controller module to move water between the solar collectors and the hot water storage tank. See Guide to Heating System Circulator Pumps & Circulator Relays for details.
An expansion tank absorbs the pressure increase created in the (closed) system when water is heated. See Guide to Heating Boiler Expansion Tanks for details.
A pressure and temperature relief valve is provided on the hot water tank for safety
An air vent valve is provided at the solar collectors to avoid the piping becoming air bound, purging un-wanted air in the water circulation loop.
A tempering valve or mixing valve is installed to mix cold water in with the outgoing hot water from the hot water tank, permitting storage of more heat in the water tank without risking scalding building occupants. We discuss tempering valves or mixing valves in detail at Guide to Mixing Valves & Anti Scald Valves
A backup hot water heater is usually provided, using electricity, gas, oil, or other fuel to assure that there is adequate hot water when weather conditions do not provide enough solar energy.

As energy costs continue to increase the payback-time for the cost of solar panels and piping installation for solar hot water systems will continue to improve.

Especially in areas that receive adequate sunlight we should expect to see an increase in popularity of these systems.

A Comparison of Alternative Hot Water Heaters & Sources

Here we describe the characteristics of these water heating methods:

  High Efficiency Water Heaters such as direct-vent gas-fired water heaters
  Indirect-fired Water Heaters which use a separate heating boiler to produce a larger quantity of hot water
  Instantaneous Water Heaters point of use systems that have little or no standby energy losses
  Multiple water heaters in parallel to increase total hot water quantity
  Multiple water heaters in series to stage hot water heating for varying levels of demand
  Range Boiler Water Heaters an older form of indired-fired hot water heating used with separate heating boilers
  Side Arm Coil Water Heaters similar to instantaneous and tankless coil water heaters, often used with range boilers
  Solar Water Heaters using solar collectors, an indoor water tank, pump and controls, using minimal "on-grid" energy
  Tankless Coil for Hot Water a heat exchanging coil immersed inside of a heating boiler heats provides (somewhat limited) hot water, various tricks can significantly improve the safety and water quantity available

The characteristics of various water heaters such as life expectancy, cost, safety, and capacity are discussed at WATER HEATER PROPERTIES

Ways to improve hot water quantity, pressure, and flow are discussed beginning at HOT WATER IMPROVEMENTS and continuing at HOT WATER QUANTITY IMPROVEMENT.

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

WATER HEATERS
ALTERNATIVE HOT WATER SOURCES
  High Efficiency Water Heaters
  Indirect-fired Water Heaters
  Instantaneous Water Heaters
  Multiple water heaters in parallel
  Multiple water heaters in series
  Range Boiler Water Heaters
  Side Arm Coil Water Heaters
  Solar Water Heaters
ANTI SCALD VALVES
CHIMNEY INSPECTION DIAGNOSIS REPAIR
Clogged Piping & Hot Water Flow
ELECTRIC WATER HEATERS
GAS FIRED WATER HEATERS
  DRAFT HOODS - gas fired
  Gas BTUH & Cubic Feet
  GAS PIPING, VALVES, CONTROLS
  SPILL SWITCHES - Flue Gas Detection
HOT WATER IMPROVEMENTS
HOT WATER QUANTITY IMPROVEMENT
  Alternative Hot Water Sources & Methods
  Anti-Scald Valves & Hot Water Quantity
  Clogged Piping & Hot Water Flow
  Extra Tanks to Increase Hot Water
  Insulate Hot Water Piping
  Insulate Hot Water Tank?
  Larger Diameter Water Supply Piping
  Tankless Coil Hot Water Increase
  Temperature of Hot Water is Too Low
INDIRECT FIRED WATER HEATERS
ODORS IN WATER
OIL FIRED WATER HEATERS
  DRAFT REGULATORS - barometric dampers
  OIL BURNERS
  OIL BURNER NOISE SMOKE ODORS
  OIL PIPING
  OIL TANKS
MIXING VALVES
RANGE BOILERS
RELIEF VALVES - TP Valves
SEWER GAS ODORS
SOLAR HOT WATER HEATERS
TANKLESS COILS
  Clogged Piping / Tankless Coil & Hot Water Flow
  Mixing Valves
  Tankless Coil Leaks
  Tankless Coil Hot Water Increase
WATER HEATER PROPERTIES
  Electric, Gas, Oil Water Heater Efficiency
  Water Heater Life Expectancy Comparisons
  Water Heater Operating Cost Comparisons
  Water Heater Purchase & Maintenance Costs
  Water Heater Water Quantity Comparisons
  Water Heater Recovery Speed Comparisons
  Water Heater Safety Comparisons
More Information

Technical Reviewers & References

Particular thanks are due to experts and also consumers who read these articles and suggest corrections, changes, and additions to the material. Content suggestions, technical corrections and content critique are invited for any of the content at our website.

Daniel Friedman - InspectAPedia.com ^TM Website Author/Editor
Thanks to Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Critique, contributions wanted: Contact Us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

More Information on Inspecting and Repairing Heating Systems

Carbon Dioxide Gas Toxicity
Carbon Monoxide Gas Toxicity, exposure limits, poisoning symptoms, and inspecting buildings for CO hazards
Dust from HVAC? An Investigation of Indoor Dust Debris Blamed on a Heating/Cooling System Reveals Carpet Dust
Goodman Furnace High Temperature Plastic Vent HTPV safety recall US CPSC notice
Home Heating System Should Be Checked [for proper venting and for CO Carbon Monoxide Hazards - DJF]
Inspection Procedures for Oil-Fired Heating Systems Detailed step by step approaches for inspecting complex systems]
Lennox Pulse Furnace Safety Inspection/Warranty Program: Carbon Monoxide Warning
Oil Tanks - The Oil Storage Tank Information Website: Buried or Above Ground Oil Tank Inspection, Testing, Cleanup, Abandonment of Oil Tanks
Oil Tanks Above Ground, UL Standards, guidance for home owners, buyers, and inspectors
Plastic Heating Vent Pipe & Other Heating Safety Recall Notices
Weil McLain Model GV Gas Boiler/gas valve CPSC recall/repair
Domestic and Commercial Oil Burners, Charles H. Burkhardt, McGraw Hill Book Company, New York 3rd Ed 1969.
National Fuel Gas Code (Z223.1) $16.00 and National Fuel Gas Code Handbook (Z223.2) $47.00 American Gas Association (A.G.A.), 1515 Wilson Boulevard, Arlington, VA 22209 also available from National Fire Protection Association, Batterymarch Park, Quincy, MA 02269. Fundamentals of Gas Appliance Venting and Ventilation, 1985, American Gas Association Laboratories, Engineering Services Department. American Gas Association, 1515 Wilson Boulevard, Arlington, VA 22209. Catalog #XHO585. Reprinted 1989.
The Steam Book, 1984, Training and Education Department, Fluid Handling Division, ITT [probably out of print, possibly available from several home inspection supply companies] Fuel Oil and Oil Heat Magazine, October 1990, offers an update,
Principles of Steam Heating, $13.25 includes postage. Fuel oil & Oil Heat Magazine, 389 Passaic Ave., Fairfield, NJ 07004.
The Lost Art of Steam Heating, Dan Holohan, 516-579-3046 FAX
Principles of Steam Heating, Dan Holohan, technical editor of Fuel Oil and Oil Heat magazine, 389 Passaic Ave., Fairfield, NJ 07004 ($12.+1.25 postage/handling).
"Residential Steam Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
"Residential Hydronic (circulating hot water) Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
"Warm Air Heating Systems". Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
Heating, Ventilating, and Air Conditioning Volume I, Heating Fundamentals,
Boilers, Boiler Conversions, James E. Brumbaugh, ISBN 0-672-23389-4 (v. 1) Volume II, Oil, Gas, and Coal Burners, Controls, Ducts, Piping, Valves, James E. Brumbaugh, ISBN 0-672-23390-7 (v. 2) Volume III, Radiant Heating, Water Heaters, Ventilation, Air Conditioning, Heat Pumps, Air Cleaners, James E. Brumbaugh, ISBN 0-672-23383-5 (v. 3) or ISBN 0-672-23380-0 (set) Special Sales Director, Macmillan Publishing Co., 866 Third Ave., New York, NY 10022. Macmillan Publishing Co., NY
Installation Guide for Residential Hydronic Heating Systems
Installation Guide #200, The Hydronics Institute, 35 Russo Place, Berkeley Heights, NJ 07922
The ABC's of Retention Head Oil Burners, National Association of Oil Heat Service Managers, TM 115, National Old Timers' Association of the Energy Industry, PO Box 168, Mineola, NY 11501. (Excellent tips on spotting problems on oil-fired heating equipment. Booklet.)

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Guide to the Basics of Solar Hot Water Heating Systems HeatAPedia ©