Storage heater alternative.... Infrared vs lpg vs Air source heat pump 12 April 2021 at 9:50AM in LPG, heating oil, solid & other fuels 83 replies 3.2K views

matelodave

Even with all the inefficiences gas is stil far cheaper than leccy - it would have to have an efficiency of around 20% before if became comparable in cost.
Even electric heaters (unless thay have fans in them) work like radiators and heat your head rather than your feet and get just as hot as hot water rads so what point are you trying to make.
Just do the sums - if it takes around 3kwh to heat 50litres of water 50 degrees. = 3kwh at 15p for leccy = 45p and let's be generous and say that your gas boiler is around 50% efficient, so you'd need 6kwh of gas at 3p/kwh = 18p

lohr500

Well, I will continue to heat our hot water in the summer using our oil boiler rather than Eco 7 electricity. All the calculations and measurements I have done, including monitoring the boiler oil consumption with an in line flow meter, tells me it is more cost effective to use the boiler.   

Reed_Richards

To be fair, you need to account for the volume of water in the pipes between the boiler and the hot water cylinder.  In my case these are 28 mm pipes, internal diameter 26.2 mm, so radius 1.31 cm therefore about 539 cc of water per metre of pipe.  Round trip distance is about 28 m so about 15 litres of water in these pipes, plus the volume inside the coil and the volume inside the boiler.  When comparing gas and electricity that does not make a huge difference to the economic balance but it is certainly enough that it should not be ignored.

Previously I had a combi boiler and 22 mm pipes and I had to run-off a bucket and a half of water (which is about 27 litres) before the hot tap at the other end of the house to the boiler ran hot.   So perhaps my 15 litres calculation is too optimistic?