Home Forums General Discussion Using PV systems to heat hot water Reply To: Using PV systems to heat hot water

Phil Squire

Brilliant posts people. Just what has been running around in my mind too. With no security of supplying our energy retailers with green elec. using the energy at source is the bomb!

I would love someone to model this – anyone got a nifty programme that would calculate rates of return/payback etc for a PV system tied to the grid.

FYI http://www.pvcalc.org does a reasonable job of calculating the returns on varying PV systems, lifetime, cost of money, elec tarrifs etc. The main issue I have when comparing a PV systems financial returns when comparing to the” risk-free” (unless you’re in Cyprus) rate of return in a bank acct, is that depreciation rates are not straight line. You lose at least $3000 in the first year, since the install cost and removal cost are lost in asset if you need to move or sell the system. But for  a homeowner with a long tenure (over 15 years, it’s a money maker on a big scale (percentage wise).

Interesting to see the Vector offer in Auckland. $2000 up front and $80/month for a Vector owned system 3kWp on your roof – also has a lithium ion battery that they can use for load control.