In hot water

I have a customer who would like to install 6 125 watt panels on his roof and then feed a hot water heater with 24 volt elements in it. The heater would feed the exsiting domestic hot water boiler and would make up as much as possible to reduce the oil consumption. Great southerly exposure in northern CT. Most of my install work has been with 50-100 watt systems for radio and scada on pipelines and I have never even given it much thought....any pro or con sides to doing this? No batteries, no controller,............any thoughts...?


  • BB.
    BB. Super Moderators, Administrators Posts: 33,477 admin
    Re: In hot water

    It is a very expensive way to make heat... A solar PV panel costs between $4-$5 per watt. A solar thermal panel costs around $0.50 per watt and is about 1/3-1/4 the square footage of the equivalent solar PV panel.

    Of course, there is all of the plumbing, pumps, drains, antifreeze, and complexity of a solar thermal water heating system.

    Here are a couple recent links on solar hot water:

    Link 1
    Link 2

    If you want to start with a kit system, look at -- was recommended by Solar Guppy as an easy to install/maintain and relatively inexpensive system.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: In hot water

    BB is right, solar electric is definitely NOT the way to go for heating water.
    There are far better ways to heat water with solar energy.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: In hot water

    in agreement with both these guys and will add that if you have the pvs already that you could charge up some batteries and have a diversion controller allow for supplemental heat to the water after the batteries receive their charge. those batteries could be used in a number of applications of the very least of which may just be a backups for the electric. thermal panels will yield more btus than pvs for the same area on the roof.