nowty wrote: ↑Fri Aug 06, 2021 11:18 am
I have a gas combi but installed a 300 litre pre-heat tank which can be heated via my heatpump or twin immersions. Between April and Sept the gas combi is turned off and I rely on the heatpump to get the water to 50 degrees and then the immersions to heat it up the rest of the way to 60 degrees. When its summer and unlimited solar PV, I just use the immersions via the immersuns to heat the water up all the way.
Between Oct to March the gas combi is turned on and I limit the heating of the pre-heat tank to 40 degrees via the heatpump because the combi sometimes behaves erratically on pre-heated water above 40 degrees.
In winter the central heating is run on the heatpump when its cheap rate and sometimes on the batteries if its not too cold outside. But the gas is needed in the coldest weather. With the help of Ripple, I will also dump power at cheap rate to the storage heaters and this helps reduce the gas usage. I tried this two winters ago and it worked great but was more expensive than using gas but this coming winter I should get the help from the Ripple wind turbine so will try again on the storage heaters to displace more gas.
Sorry to say but gas needs to be more expensive to drive the right behaviours. That's not going to be politically popular but its got to happen in order to nudge people to heatpumps and more insulation. Maybe an annual escalator on the price of gas will be the least unpopular option. It worked for Petrol, at least for a few years before we had the national protests.
I agree, gas is too cheap per kWh.
Storage heaters would work if Agile did what it was supposed to: provide several hours a day of near-zero or negative priced electricity regularly through the winter when the north sea wind turbines get spinning. But it seems they'd rather waste the energy through curtailment. I read that wind was curtailed on 75% of days in 2020, that is free, renewable energy going to waste. I'd use it, and I'm sure you would too!
A heat-pump in ideal conditions, on the Go cheap rate, just about beats gas. But if your pump is air-source and the outside temperature is below 0℃ then gas wins even on the cheap rate. Storage heaters are double the cost of gas even on the cheap rate. Outside of the cheap rate on a ToU tariff you're burning money with any kind of electric heating.
If the sums shift then I'd fit an air-to-air heat pump to add a bit of warmth in the shoulder months. But it'd need to match gas at standard rate and justify purchase/installation costs on the cheap rate.
