Solar Heating

Often overlooked as a renewable energy source. Solar thermal technology has much potential for Wisconsin’s ever changing climates. These products produce heat energy, as opposed to solar photovoltaics (PV), which produce electricity.

Alternate Energys solar thermal applications can provide energy for your home or business’s hot water needs, heating or cooling, and even electricity. This technology is widely used for pool heating and to generate domestic hot water, however, space heating is quickly gaining ground.

Types of Hot Water Systems

Systems are typically characterized as passive or active, open- or closed-loop.

  • Passive systems use no electricity but instead rely on the convection movement of water or solution through panels. Less expensive, these systems are less efficient but easier to maintain than active systems.
  • Active systems use electricity to circulate water or a solution through its collector panels. Active systems are generally more efficient, also more expensive.
  • Open-loop systems circulate potable water through collector panels and are not widely installed in Wisconsin due to our tundra-esque temperatures.
  • Closed-loop systems circulate a brine solution through its panels and is an ideal energy alternative for our cooler climates.

Collector Types

Flat Plate Collectors are dark glazed, insulated, weatherproof panels through which a brine solution circulates. A dark glazing absorbs solar radiation from the sun that is transferred to the circulating fluid. These panels are effective in our snowy climate as their flat shape and radiating heat help to shed snow quickly.

Photo from U.S. Department of Energy

Evacuated Tube Collectors have rows of transparent glass tubes and utilize a vacuum to transfer heat. These collectors give more even output over a span of time and are more expensive. Because these tubes do not radiate heat, they will not shed snow and become less effective after a hearty Wisconsin snow storm.

Photo from U.S. Department of Energy

Space Cooling

Wisconsin’s humid summer require our homes to utilize air conditioning systems, albeit a small percentage of the year. Solar cooling is a new technology to generate cooling when it is needed the most. Clearly if your building is relying on window units, you are a strong candidate for solar thermal cooling. Buildings with a central chilled water system can reduce their dependence on chilled water by installing a solar thermal cooling system.

Space Heating & Pools

Have us provide you with a site assessment to ensure the building’s roof is in a great position to receive optimal sunlight. Solar thermal can easily provide hot water to a hydronic heating system, in-floor radiant system or heat in a water to air heat exchange system. Solar thermal & radiant provide excellent paybacks for pool heating. Pool systems demand lower water temperature and can be easily designed with solar systems.


LEED projects can earn easy points for installing solar thermal. Points vary by category.

LEED Category Maximum Points
Existing Buildings 4
New Construction 3
Commercial Interiors 1
Homes 10