Solar PV to power electric rads / underfloor

Martyn1981

Hiya Dave-o. This is not a criticism, but I still think you should split the PV and leccy heating ideas into two separate decisions.

Yes the PV will help a little towards the heating, but it will only be a tiny amount. So the leccy/log burner heating idea needs to stand on its own two feet first.

You can put the FiT income against the leccy bill, but I think that's cheating. It's no different to putting it towards a car lease, then saying the car is cheaper.

One idea that may help with the heating bill is to use a small ASHP, simply a £500 (plus fitting) A/C unit, located where it could help add some heat to the house in the shoulder months (Mch/Apr & Sept/Oct) when you'll have a bit more spare generation. It might add a little in winter, but if you are diverting to a hot water tank, then there won't be any spare left. However, if it stands up to scrutiny financially as a shoulder month heat source, then some additional use in the winter could still triple the value of the leccy being used.

Here's a thread where we discussed the idea previously.

Mart.

dontgetcaught

" if you are diverting to a hot water tank"

Using a heat/thermal store is not diverting to a hot water tank.
Thermal stores work by holding the hot water ready to be used in either heating or hot water. There may be merit in also having a ASHP.
During the year with a 3.64 kwh solar pv system in Cornwall will generate similar to these figures from a graph from Teighmouth @ https://www.generaytor.com/143094/charts for 2014
jan 86 kwh
feb 181
mar 352
april 416
may 467
june 514
july 543
august 415
september 339
october 199
november 97
december 77
Using any surplus Kw's makes sense as you still get your 50% FIT, even if you use it, Dave seems to have the rest sorted with a wood burner which I assume would be on some of the time from oct thro to march, for the times outside this that there is a requirement for MORE heat then electricity from the grid will not be over expensive compared with the overall cost of Boiler/servicing etc given that a boilers life is something like 10-15 years so I am told so minimum £50 for the annual service and capital cost over 15 years @ say £133 (£2000/15) @ 15p per unit it looks like there is 1200 kwh of electricity before it starts to cost, assuming you never have a repair of the gas system in 15 years.

Cheers