Solar Hot Water (Solar Thermal)

Video: Chris Rhoda, and his daughter Emma, talk about what going solar has meant for them. Their 3,000 square foot home no longer uses oil!

Save Money With Free Hot Water from the Sun

Most homes in Maine, New Hampshire, and Massachusetts heat their water using high-mass oil boilers. All summer these boilers must stay on, sporadically firing to heat domestic hot water.

Solar hot water solves this problem by providing solar-heated water during the summer months, allowing you to:

  • Shut down your home's boiler from May through October
  • Save 100s of gallons of oil or propane
  • Have reliable hot water throughout your home

Not only do homes with solar hot water save money and C02 emissions, most customers report that showers with solar hot water just feel better!

Professional System Design and Installation

Arrowsic, Maine - Solar Hot Water and Solar Power
Solar hot water panels (lower right) paired with a grid-tied solar electric array for a customer in Arrowsic, Maine.
After 10 years installing and servicing solar hot water systems in the harsh climates of Maine and New Hampshire, we've distilled our knowledge into a design we believe to have the highest efficiency and longevity, with the lowest installation costs. Our designs are proven in the field with over 1,000 happy customers in Northern New England.

ReVision Energy's solar thermal systems are compatible with any existing water heating system, whether it's electric, gas, or oil-fired. During our free solar site evaluation one of our highly trained, experienced solar designers will visit your home and evaluate whether a solar energy investment makes sense for you.

Our systems featured a 'closed-loop' design, meaning that we use nontoxic antifreeze that never comes in contact with your drinking water to exchange heat. Our systems operate trouble-free throughout the winter, and are designed for automatic overheat protection so that you can leave the system unattended in summer without issues.

0-down, 2.99% financing is available through ReVision's Own Your Power solar loan program.


How Solar Hot Water Works

Solar hot water works by:

  1. Sun hits collectors on the roof, heating non-toxic antifreeze mix and triggering pump to start running
  2. Pump moves solar-heated mix from roof into heat exchanger located in storage tank in basement, indirectly heating water supply
  3. Hot water from storage tank pumps out to sinks, showers, dishwashers, etc.
  4. Backup automatically integrated to provide hot water during extended periods of cloudy weather

Am I a Good Candidate for Solar Hot Water?

Solar hot water makes the most sense for:

  • Homes inefficiently heating water now (i.e. using an oil boiler or old electric tank)
  • Primary homes or homes used year-round
  • Homes with high hot water loads (families of 4+, apartments)

Use our interactive solar hot water calculator to see what kind of system might work for your home:

Solar Thermal Calculator

Which State Do You Live In?
How Many People Live in Your Home?
Do You Live in Your Home Year Round?
How Much Hot Water Do You Use?

How Much Does It Cost?

Gross Installed Cost:   $
Federal Tax Credit: - $
State Rebate: - $
Total Incentives: - $
Net Investment:   $
Est. C02 Offset Each Year:     lbs
Est. Hot Water Used Daily:     gal
Estimate only, actual quote varies based on market price & complexity. State rebates may vary due to project size.

Your SHW System

Welcome to the Solar Calculator

This version of our solar calculator lets you size a solar hot water system to meet your home's needs. Systems are sized based on hot water need - a product of the number of a home's occupants and relative water use.

PV System Image

Get a Firm Quote Today!

What Goes In a Solar Hot Water Job?

ReVision Energy borrows from leading European solar thermal system designs for robust, resilient systems designed to sustain decades of New England winters. Our solar hot water systems are a closed loop design, meaning that the fluid that passes through the solar hot water collectors never comes in contact with your drinking water supply (and thus can be winterized), and feature the industry-accepted best practice of steamback design for overheating.

There is much more in a solar hot water quote from ReVision Energy than the quotes by most other dealers. Here is a brief summary of the major components and how/why we select them.

Solar Hot Water Collectors

There are two major designs of solar hot water collectors - evacuated tube collectors and flat plate collectors. These days we tend to prefer flat plate collectors over evacuated tubes due to superior year-round performance, quality of workmanship, and reduced long-term maintenance vs. tubes.

Factors such as roof pitch, roof layout, expected hot water load (and seasonal demand), expected snow load, aesthetics and cost are factored into the decision-making process as one of our solar design professionals works on a customized quote for you.

The Solar Storage Tank

Clean Green Energy Solar Power Hot Water Tank with Heat Exchanger

Stiebel Eltron 105 Gallon Solar Hot Water Storage Tank with Solar Circulating Pump

A purpose-built storage tank is critical to the success of a solar hot water system. It's critical that a solar storage tank be:

  • Built out of rugged materials to perform well for the span of the system's life (20+ years)
  • Well-insulated, with 2-3 inches of foam insulation to ensure minimal heat loss overnight from solar heated-water
  • Properly sized for your household's needs; it should neither be too small (so that it has difficulty keeping up with demand), or too large (so that solar is never effective at providing a significant fraction of the home's domestic hot water needs)

For installations with an oil boiler as backup, we choose Stiebel Eltron tanks as they manufacture the best dual coil solar storage tank on the market. Stiebel's purpose-built tanks are super-insulated with 3 inches of urethane foam to store precious BTUs harvested from the sun and its two internal heat exchange coils allow for easy integration with almost any boiler-based heating system. This porcelain-lined steel tank comes with a built-in sacrificial anode rod with a wear indicator that is easy to view and replace if necessary.

For systems requiring electric backup, we typically will install an 80 or 119 gallon Caleffi solar tank, comprised of 2" of non-CFC rigid foam insulation which offers R16 insulating value.

Pump Controls

The "brains" of the solar hot water system is the pump station. Ours feature a high-quality 3-speed circulator, check valve/ball valve, pressure relief valve, fill and drain ports, flow meter and sight glass, temperature gauge and pressure gauge. System operation is governed by a variable speed differential temperature solar controller that is able to harvest more solar energy than DC-based systems. Our smarter RESOL controllers will harvest more thermal energy than a solar-panel + pump system during low-light situations such as early in the morning and in overcast conditions.


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Cape Elizabeth, Maine - Solar Hot Water

We love getting hot water from the sun. The installation looks fine on our old farm house.

This summer we had 13 people living, showering, cooking and doing laundry here and the furnace didn't go on even once. Hooray!

Red and Louise Sullivan
Two Lights Rd., Cape Elizabeth

More Customer Testimonials

More updates from our solar blog with news from Maine, New Hampshire, Massachusetts, and Vermont.