If you’re thinking of installing active solar heating systems or are just wondering about its true benefits, all I know is that it is the most cost-effective when they are used for most of the year. Which means that you need to have good solar resources. AZ, for example, will be a good place to have solar heating. If you currently use electricity, propane, and oil heat to heat your house, solar heating system will make the cost go much lower. You might be able to receive sales tax exemptions, income tax credits or deductions from your state government also.
It’s true that the system will not come cheap. The cost of an active solar heating system starts from $30 to $80 per square foot of collector area installed. But your fuel bills will be reduced so much even just in the first month. You can even use it to heat water and to generate electricity. If you’re also environmentally responsible, it will reduce air pollution and greenhouse gases. So if you know that you’ll stay in the house for a long time, then invest in a system.
Source: EERE