Pre Heated water into Oil Combi

[JohnD]

Yeah there's an install cost, I've no idea what the current state of grants/deferred payments or other inducements is, every time I've looked the payback time has been in decades due to base electricity cost. If your base electricity cost is zero, payback should be about 4 or 5 years on a £5k install swapping from gas or oil

to save £5k in 5 years, I would have to use zero electricity and zero gas

impossible.

 

[MeldrewsMate]

...I am a person who loves data, and I have digital sensors on everything. I have already dropped usage from 9L per day to 6L per day by heating the buffer tank, remember my UFH runs at 40C only so the 3Kw heater does a great job. I have top of the range sensors and data logging so know exactly where my savings are.

My first point, as a data lover, is to correct your errant data. The kilowatt has the symbol kW, not Kw; and for the benefit of @oldbutnotdead , a kilowatt-hour per hour is usually quoted as a kilowatt.

My second point, lucky you OP, is are you sure you have a 24 hour supply of free 'lecky at 7kW? This sounds like a scene from the TV show Still Game! In Dundee? In Dundee where the sun only shines 2 days per year? Do you have it piped in from Lancashire, where the sun shines out of Whippet's ars*s 24/7?
If you do, get yourself a large 7kW ASHP, a large thermal store, and start selling heat to the neighbours!
ASHP heats thermal store to 40C, 2 x 3kW immersion heaters takes it to 80C, the rest is pure luxury, but don't tell the Ukrainians; they're freezing their bo**ocks off right now.

 

[oldbutnotdead]

Yeah, suppose kWh/h was a bit tautological- apologies