Cost to heat DHW oil v electric?

[ericmark]

To try and compare a direct water heater to an indirect water heater one needs to look at losses due to it being indirect.

Where the boiler is super efficient and pipe work is minimal then no question gas/oil is cheaper.

My problem is easy to measure electric, but not so easy to measure gas or oil, no good putting a clamp on meter on an oil or gas pipe.

 

[JohnW2]

To try and compare a direct water heater to an indirect water heater one needs to look at losses due to it being indirect. Where the boiler is super efficient and pipe work is minimal then no question gas/oil is cheaper.

Yes, but per what I just wrote, it sounds as if you are probably just thinking of the 'physics'.

As I wrote, using Stephen's figures, when one considers the 'non-physics' issues, gas/oil would still be cheaper even if the boiler was very inefficient and the pipework very long - because he is being paid almost 4 times more for not using his solar than he has to pay to use gas instead.