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:
1 Pool heat pumps also cost $2,000 to $3,000, depending on brand and size. 2  Solar pool heaters, on the other hand, cost $100 for a small above ground pool brand and $1,000 (or above) for a larger in-ground solar pool heating systems. 3  These prices reflect the actual heater and will not include the installation. The unit itself can cost $1,000 to $1,500 without the installation. 2  Therefore, for a typical 15 x 30 pool, the unit price would be $1,200 and the installation fee can be as high as $1500, bringing to the total to the mid-$2,000âs.