How much does electricity cost? How much does gas cost?
Following the Government paring back of the price rises the graph below has been updated – thank goodness. So 34p for electricity and 10.3p for gas.
The chart here shows how many kW.hrs £1,000 gets you for each type of energy source. Electricity is disproportionately the most expensive source of power. Your average house needs about 20,000 kW.hrs to heat over the winter – 1” to the right off this chart then and about £7,000! – so electric heating will be out of the question but the chart raises other issues which we’ll discuss below.
You see advertisements for electric heaters that are 100% efficient. They may deliver every kilowatt they consume but the claim is a meaningless dupe for the technically illiterate, they still use the most expensive power available.
Heat Pumps vs. condensing gas boilers
On a typical COP of 3 your electrical input is trebled but the latest hike still makes this about the same as natural gas. Conclusion? Forget all this stuff about heat pumps and make sure you have a modern condensing gas boiler while you can still get one. Heat pumps only make sense if you have solar panels to make them run mostly free but it’s dark after tea time in winter just when you need the heat.
Don’t ignore mini-split aircon units though. For about £1,200 they are proper heat pumps and with solar panels the free summer cooling is welcome. For most people, and the planet, this is the answer but strangely the government offers no help here. To reinforce this point my 10 panels easily run my mini-split during daylight hours in October and the house stays chill free. The aircon in summer was fantastic with cool air washing across the whole ground floor.
Noisy high maintenance things and so close to gas so why bother. Another glass of wine by the pellet stove anyone?
Oil looks like a reasonable choice here but there are some negatives that need to be aired. Oil boilers don’t modulate so they short cycle a lot and don’t run very efficiently. Trying to get your oil boiler to run efficiently in condensing mode could be a challenge. Oil is easier to steal and the tanks need condensate sludge cleaning out from time to time. LPG looks very attractive in comparison and locking in to the longest deal could be the best choice. Another consideration is that a modulating gas boiler makes a much better partner to a heat pump if you ever want to go to a hybrid solution.
Near the top of the energy sources here so worth having that wood burning stove. An open fire is far less efficient especially when it’s really cold outside and negative efficiency is even possible. Anyway, a stove makes a lifesaving backup in the event of power cuts – always a possibility. However, unless you are huddling round the wood burner with the rest of the heating off it would be cheaper to heat a whole house with an LPG boiler.
The star of the show at the moment and you can lock in these rates for two years. So, gas cookers good – electric cookers bad.
Considering a heat pump? No way. Dig a hole in the garden and go for LPG. Note that although the bar for LPG looks good on the graph it could still be made even longer with simple system tweaks to make the boiler run more efficiently.
As I’ve said, same as a heat pump and 3 times better than electricity. Not brilliant though but there’s a tweak to think about. Your gas boiler will probably be a condensing type but that only works when return temperatures are below 55c so you need to turn down the output temperature to about 75c and see how that works. If you still get a cloudy plume on the exhaust flue then turn it down a bit more. Do this and you might get near the 97% efficiency the boiler boasts it can do. The difference this makes to your bills will be huge. If you are turning off radiators to save energy the return temperature will rise so it’s better to turn down the boiler as your first move. Elsewhere on this site you’ll find a simple hack that will enable high radiator temperatures and low return temperatures; probably the quickest and cheapest way for most people to get over 10% heating bill reduction.
Of course, like incandescent light bulbs, all non-condensing boilers should have been in the skip long ago but even more so now.
Octopus offer late night electricity for car charging at 12.5p/kW.hr. That is very good indeed and works for everything, not just cars. A heat pump kicking on in the early hours is super cheap and not only off this chart but off the page too. A kW.hr for about 4p when running a heat pump; makes you want to rush out and buy a mini-split immediately. Storing this energy for later is the main issue but running the immersion heater and charging up night storage heaters directly is an idea.
You might like to explore vehicle to home to storage ideas here. Heating News – Spring 2022
Hard to chart here because the power is free but the sharp rise in electricity prices means that PV payback times have tumbled. Take a cluster of three panels for around £1,000. They will produce over 1,000 kw.hrs over a year which is worth £340 if you used it all. A three year payback then. More panels decrease the likelihood of consuming all the production but a diverter, like the Eddi, to power your immersion heater or a car charger will help you consume all you make.
A lot of work went into the comparisons and I hope they are accurate. However please check for yourself before committing to any changes. The figures are skewed for the efficiencies of the kit that is using them so, for example, gas boilers are calculated at 86% efficiency rather than the 97% that might be theoretically possible.
Interesting article. What should the return temp on a condensing boiler be if you have UFH?
Hi, Whatever you are powering the return temp needs to be below 55c …. you should be there already with UFH
Great article – don’t understand why mini splits aren’t pushed