In order to use solar collectors for heating support, it should be remembered that the system will need 2-3 times more than hot water, but during the summer, if there is no rational use of heat, such as a swimming pool or heated basement, the equipment will be idle.
If someone promises you that a 10 m2 absorbing surface will be able to heat a 100 m2 terraced house, then you know - you are lying lying in front of your eyes.
If the goal is to feel effective heating support, but do not experience collector downtime in summer, then you should look at the combination of flat vacuum collectors TS400 and heat pump DUO. Such a system can get 3-5 times more energy from solar collectors during the heating season, because all low-temperature solar collectors are used. Also temperatures of +20o C and even 0o C in solar collectors are applicable, which are usually unusable for heating systems. The number of solar collectors for heating support in the DUO system is smaller than in other solar heating support systems, but flat vacuum solar collectors must be used
TS400. Other solar collectors are perfect for water heating, swimming pool heating, etc. but only TS400 flat vacuum solar collectors can be used in systems with heat pumps. The rest will be damaged by condensate that will form when working at such low temperatures.
In Latvia, in cooperation with the ThermoSolar plant, such a DUO heating support system has already been installed. It works in real conditions in a populated private house and can be viewed in person by anyone interested.