Do solar water heaters have boosters

All solar water heaters come with some sort of backup boosting for periods of low sunshine, such as during cloudy days. Most systems have an electric booster element fitted which can be operated on a cheap night rate tariff. Other boosting methods are gas or a slow combustion wood stove. The amount of boosting required will depend on the location.

Some gas boosted solar water heaters have a special controller to only allow boosting at certain times of the day. This prevents boosting occurring in the morning when large amounts of water are drawn off, allowing the water to be heated by the sun during the day, with boosting only occurring at night.

Another option is to use an instantaneous gas water heater as a booster. These heat water as it passes through them, and can be installed between a solar water heater and the house taps to heat the water to a predetermined level if there has been insufficient sunshine to do so. Some models can sense the temperature of the water from the solar heater, so if the water is already hot enough, then the instantaneous heater will not heat the water further. Instantaneous heaters that do not sense the input temperature are not suitable for solar boosting. These heaters are significantly more expensive than normal gas heaters.

It is also possible to use your existing gas or electric hot water system and connect one or more solar collector panels to it. The water heater would need to have a suitable capacity, and be less than five years old to make it worthwhile.