It cost me 153 gallons ($384) to run my boiler from last March to last November, 10 months. I've been thinking of making my boiler a cold starter and putting in either a tankless water heater or point of use supplies. A whole house electric tankless takes 240 volts at 120 amps so that's out, I only have 100 amps coming in.
Since I already have oil, an oil fired tankless ($1500) would be easy.
Point of use tanks (6gals) are around $155 each and tankless point of use heaters are about $285 and take 12kw. I have never used 6 gallons of hot water at any sink session. They say the tankless point of use cannot be used with a shower. Why is that? I have a water saving shower head that is cut back 75% with a valve.
I could also get by with a 20 gallon standard water heater just fine.
What's the best energy saving combination?