If you are using the word costs as a noun, then it is plural. You would say the costs are..., never the costs is.... If you are using it as a verb, then it refers to a singular object: It costs a lot of money They cost a lot of money.
The average solar water heating system can cost between $6,300 and $7,200 depending on the tank size and need.We help to make getting a solar water heating system installed in your home both easy and affordable.We provide two rebates to help you offset costs:he Cost of a Solar Water Heating System. The average solar water heating system can cost between $6,300 and $7,200 depending on the tank size and need. We help to make getting a solar water heating system installed in your home both easy and affordable. We provide two rebates to help you offset costs:
Solar thermal (ST) is one of the most cost-effective renewable energy systems. Solar thermal water heating systems collect the sun's energy in the form of thermal or heat energy. The system can save a major portion of your utility bill. This solar thermal system will cost about $4,600 US (with the price decreasing all the time). 2  A solar pool heater, popular and practical, is an open loop system. 3  It's called this because water circulates back into the pool, which is (of course) an open system.