plumbing to the solar gear.

Drainback Tanks

If you're installing a drainback system, you'll also need a specialized reservoir tank. Drainback tanks are smaller than primary tanks, usually containing between 5 and 20 gallons. They are like their bigger siblings: made of lined steel or fiberglass, with insulation and sometimes a heat exchanger. Many also have a little sight glass on the side so you can monitor the water level easily.

Used tanks

Some solar enthusiasts like to cut costs by looking for a quality used tank. This is perfectly acceptable, given that most steel versions have a life of up to 30 years, and their plastic and fiberglass alternatives last almost indefinitely.

The important thing if you decide to buy a pre-owned tank is to check for signs of corrosion inside, outside and at the connections. Unless you're buying from someone with a very good reason to sell, the majority of used tanks either leak or are on the verge of doing so.