Solar Powered Radiant Heating

Radiant heating is compatible with solar hot water systems, contrarily to what happens with heating through baseboards and other radiators. But the final cost of such a solution is high.

The temperature issue

Radiant heating systems require water temperatures up to around 100ºF/38ºC, which can easily be generated by solar collectors (on the contrary, baseboards-radiators demand high temperatures which usually can't be attained with solar systems, unless you use a boiler to help to increase the water temperatures).

Sub-systems

A solar powered radiant heating system comprises two sub-systems:

- a solar hot-water sub-system
- a floor-radiant heating sub-system.

The solar sub-System

Solar radiant heating demands a larger solar collector surface and larger storage tanks than common uses of solar hot-water heaters. That's the only particularity of the system. As with other solar water heaters, the solar heating system depends on climate elements and personal choices. See: Solar thermosyphon systems, Solar drainback systems and Solar anti-freezing systems.

The type of collectors may vary: the evacuated-tube collectors are a suitable option (mainly in colder climates) as well as flat-plate collectors (mainly in moderate climates).

Very cold climates will demand more complex solar sub-systems, eventually supported by evacuated-tube collectors.

The Radiant heating Component

The use of solar power in radiant heating do not demand any particular adaptation to the radiant heating component. Typically, modern radiant systems use a PEX (cross-linked polyethylene ) network of lightweight, durable, plastic, with a ½ diameter, running in a “S” loop under the floor, which is perfectly compatible with solar powering.

Some radiant floor heating manufacturers present packages integrating the various components. The tubing length depends largely on climate, tubing diameter, the system adopted, etc.

Professional assessment

The implementation of a solar powered radiant heating system demands a professional assessment. It is important to define important elements like the home heating zones and local climate considerations, which only can be properly done by professionals.

The advantages

Radiant floor heating systems are highly prized for the comfort they provide, while solar hot water heating is a tested and competitive technology involving running costs close to zero. The combination of these two features produces a fully environmentally-friendly solution.

Running costs

The running costs of a powered radiant heating system can be very low, since the energy cost component is close to zero. That’s the good news, if the system is properly designed and sized, and the house properly insulated, etc.

Initial Investment

The initial investment is the bad news: common radiant floor heating isn’t exactly a cheap solution in terms of initial costs. The initial investment for any radiant heating system is high or relatively high, and that of solar heating is not exactly a low one, all the more since radiant heating demands a larger collector surface and a larger water storage capacity than ordinary solar water heating.

Prices of $10-$12 per square foot ($100 per m2) are common. But all depends on a large number of elements. Small projects will cost proportionally more, and the type of solar systems and climate conditions, or the efficiency of the insulation, will determine the final design and costs.