Solar Water Heating

Solar water heating is a long proven, reliable technology with potential to save up to 15% of a home's total energy usage at a low up front cost.

The best use for a solar water heater is to preheat domestic hot water, the more occupants the better (minimum of 2). A solar heating system can be combined to provide inputs to a radiant in floor heating system and in some cases to indoor pools.

Merlyn Power is a turnkey systems provider of solar water heaters, using a variety of well-made equipment built in Canada. We sell and install packaged systems for simple domestic preheat or built to suit for combined, or larger applications.


 Enerworks Inc., an Ontario company, is an innovative developer of solar thermal technology. Products from the company include a range of residential sized solar appliances and larger commercial systems. Residential systems feature venting collectors, self cleaning heat exchanger and a digital system performance monitor with wireless display.

Enerworks Brochure Manager application (redirect)
Controller Notes
Thermal Energy Monitor Notes

Thermodynamics Ltd., since 1981. TDL is one of Canada's longest operating solar water heating equipment manufacturers, based in Dartmouth, Nova Scotia. Their residential SDHW systems are simple, reliable, come with a full 10 year warranty and feature a solar electric (PV) powered pump for hot water provided 100% from the Sun.

Solar Boiler System Technical Notes
                     Solar Boiler Homeowner Instructions


Frequently Asked Questions

Would a solar water heater be feasible in my house?
Does the solar water heater replace my current water heater?
How much could I save?
Can I also use the solar water heater to heat my pool or house?
How big are the panels? And how much space is needed in the basement?
What is the ideal orientation for the panels?
How do you get the antifreeze up to the panels?
What happens when I have to change my roof?
Can I install a solar water heater myself?

Would a solar water heater be feasible in my house?

Hot water use; The more users of hot water in your home, the more attractive the economic performance of a solar water heater will be -- a minimum of 2 occupants are required to justify the installation costs of a solar unit.

Fuel type; the financial savings of a solar water heater will depend on what fuel it is reducing the use of. In urban environments, natural gas is common and is the least expensive fuel source. Electricity, oil and propane are all respectively more expensive and a solar water heater installed in these homes will provide a greater rate of return.

On the installation side, a feasible site must satisfy 3 basic criteria:

       i) space and exposure for collectors(32-64 square feet typical facing South-East to West)
      ii) space in mechanical room near water heater for solar storage tank and heat exchange unit
     iii) feasible routing path for solar fluid lineset to connect heat exchange unit to the collectors

Does the solar water heater replace my current water heater?

No, in a Canadian climate a solar water heater cannot be the sole source of heat input. The function of most solar waters is to preheat a storage tank of water that then feeds into a backup, conventional, heater when hot water is drawn for showers, cleaning etc. The preheated water either satisfies the thermostat in the conventional water heater or a lesser amount of fuel is used to bring it up to temperature. A solar water heater is compatible with any other type of backup, oil, natural gas, propane or electric. Any instantaneous water heaters must be temperature sensitive models, in order to accommodate for the variable temperature output of the solar unit.

How much could I save?

Year round solar water heaters will produce 40-60% of the energy needed for a typical household. Systems are sized according to occupants, so you will save a variable amount based on how much hot water you use. Dollar savings will vary based on the fuel source you use and the water heater efficiency. Generally fuel cost ranges from low to high, natural gas, electricity, oil, propane.

Can I also use the solar water heater to heat my pool or house?

The short answer is usually "No".

It is technically possible to have a solar system input heat to a pool or to help heat the house but in most cases it is not particularly cost effective. There are some exceptions, a newly built house, a radiant infloor heating system, or a small indoor or outdoor pool.

Each case for secondary heating loads must be considered on an individual basis.

How big are the panels? And how much space is needed in the basement?

The solar water heating collectors are 4' x 8', our Enerworks panels are configured in portrait style on the roof, the Thermodynamics panels are installed landscape style. Generally, every 2 occupants require 1 collector.

Space in the basement is required for the solar storage tank and the heat exchange package. In the case of any brand of system, this space is usually 3'x3'. The storage tank is usually the same size as your current water heater, 60 gallons (270 L).

What is the ideal orientation for the panels?

The ideal orientation (azimuth) for the solar collectors is always due south. Collectors can face either South East or South West without losing significant energy capture. After this range, East or West, one should consider up sizing the number of collectors recommended for the occupants. West is generally preferred over east, since ambient temperatures are generally higher in the afternoon, minimizing collector losses.

The ideal tilt angle depends on the season you want the most efficiency from and varies based on the latitude of your location. In Southern Ontario, the ideal angle for a system optimized for year round production is about 45 degrees. A summer biased system would have a much lower angle to capture the higher sun, about 30 degrees. A winter biased system would have a much steeper angle for the low winter sun, 60 degrees or higher. In the winter case, panels can even be wall mounted.

How do you get the antifreeze up to the panels?

The packaged systems use 3/8ths copper tubing, insulated to reduce heat loss and usually bundled with 1 or two wires for temperature sensing or conducting power for the DC pump. The non-toxic, propylene glycol/de mineralized water is circulated via a solar electric pump or low power AC circulator.

The lineset is usually routed to the collectors via the shortest method possible. Using the exterior of the home is common, with the lines well insulated and often enclosed for looks and protection. Routing through the interior of the home is preferred if possible, single story homes are easiest when we can use an interior wall to drop from the attic to the mechanical room. 2 storey homes are not as easy, as there usually isn't a chaseway down to the basement. Often we can run the lines from an attic, to a garage and down to the basement.

What happens when I have to change my roof?

If the roof needs to be redone, the panels will need to be removed and replaced after the work is complete. The removal process usually takes 2-4 hours and the replacement takes 4-6 hours.

Re-roofing is not a major concern but it does make sense to have a roof that is in good shape.

Can I install a solar water heater myself?

Homeowner installation of a solar water heater is only recommended for the very knowledgeable individual due to the number of skills required, however it is possible and Merlyn has provided equipment and technical support to interested individuals. For full factory warranty, self installed systems must be inspected and certified by our personnel.



        At this point In 2012, a qualifying SDHW package is eligible for a grant of $1,250 off the installed cost. However, the EcoENERGY program will expire        in March of 2012.

ecoENERGY grant

        $1250 for approved systems

Qualifying solar domestic water heaters are eligible for grants through the Federal government's home energy audit program. All of Merlyn's SDHW systems of any size will qualify for the ecoENERGY grant.

To qualify for the grants, a home must go through the energy audit process, requiring an initial and a followup assessment. Many other grants are available through the same process, such as heating/cooling/ventilation and hot water systems, windows and insulation.

There are many ecoENERGY audit organizations, Merlyn recommends the services of REEP.

Read more about the ecoENERGY grant options.



Packaged Systems

At present Merlyn installs packaged system brands from two respected Canadian manufacturers, Enerworks and Thermodynamics. Typical prices are shown below and include labour, all installation hardware and taxes.

Enerworks Inc.

1 collector         $  6,000
2 collector         $  7.500
3 collector         $ 10,500
4 collector         $ 12,000


    1 collector         $ 5,600.00       2 collector         $ 6,800.00

Multiple use and larger systems

A large system using 4-6 collectors that are integrated with multiple secondary heating loads (pool, spa, space heating) are generally priced at $12-$15,000 installed.

Space heating tie-in

There are numerous ways in which solar energy could be integrated with space heating -- the most appropriate is through radiant infloor heating. Here there are also several options depending on your infloor heating system. As space heating is based on the circulation of a heated fluid, not a flow-through (as in domestic draws), the regular installation of a SDHW unit will not necessarily provide any supplement to your radiant floors.

For the system to "take-over" from the regular space heater, a controller and some diversion valve(s) will be required, a simple scheme would cost in the range of $400-600.

Pool heating tie-in

Whether it is to heat an indoor or outdoor pool, a secondary heat exchanger rated for use with pool water flowrate and chemistry is required. These heat exchangers are $700-800. Such an application can have simple, or automated controls applied.                                             


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