Another key ingredient is the engineering that goes into the solar array. The array is sized to fit the area that the solar system is located geographically, it is also sized for the physical location and the heat load of the building/home. The system is fully scalable from the smallest off grid home to the largest warehouse or recreational center.
Some consideration must be given to accommodating the solar system. Flat roofs are typically well positioned for solar thermal panels. However sloped roofs should be a devoid as possible from roof irregularities the compromise the optimal flat layout area or shadow same.
In addition, a custom controller system manages all the systems, based on your own input, in a hands off manner. Once operational, it should last decades with only nominal service much as you would with a gas furnace or any other hydronic heating system.
It is designed to offset 50-75% of your heating needs. Performance depends on budget, location, & engineering.
Where moderate winter temperatures are expected, or locations designed with high efficiency in mind, such as LEEDs certified buildings, and/or Net Zero designed buildings, the performance can be 100% offset for heat and >70% for hot water.