Heat Pump Question

FreeBear

NedS said: Data from the 6th Nov, when I ran heating only (no hot water), shows an efficiency of 600%, and with heating and hot water combined, I'm in the 450-550% range for the first half of November (488% average)

I figured my old oil boiler was around 85-90% efficient at best. At current oil prices, this works out about the same price as gas at around 6-6.5p per kWh. With electricity currently costing ~24.5p, an annual efficiency of 375% would be required to break even with the cost of gas. Can't run your gas or oil boiler for free though when the sun shines

But surely, if you have a heat pump, you are using a tariff that gives you cheap slots to run the heating - That skews the comparative heating costs even further towards a HP being cheaper to run.

michaels

NedS said:

FreeBear said:

TractorFactor said:

NedS said:

My ASHP system will run at a minimum flow temp of around 32C, and with current ambient temps of 10-15C, it will warm the house at a rate of around 1C per hour if the temperature has been allowed to drop.

I could turn the flow temp up to 40C, for example, and it would heat the house quicker but cost more to do so, but it is very unlikely to output the same amount of heat as a gas boiler.

See, this worries me as I'd want at least 18°C.
But would this mean a heat pump would be less efficient than a gas boiler also set to 18°C.

@NedS would be referring to the outdoor temperature of 10-15°C (if I'm wrong, it will be corrected in due course). Heating the inside at a rate of 1°C per hour is very similar to the temperature increase I get with a gas boiler (currently returning an efficiency of 90-92%). With an outdoor temperature of 10+°C, I would imagine NedS is getting at least 400% out of his heat pump.

Correct re outdoor ambient temps of 10-15C.

Data from the 6th Nov, when I ran heating only (no hot water), shows an efficiency of 600%, and with heating and hot water combined, I'm in the 450-550% range for the first half of November (488% average)

I figured my old oil boiler was around 85-90% efficient at best. At current oil prices, this works out about the same price as gas at around 6-6.5p per kWh. With electricity currently costing ~24.5p, an annual efficiency of 375% would be required to break even with the cost of gas. Can't run your gas or oil boiler for free though when the sun shines

It isn't free. The pv leccy you are using could be exported for 12p per unit.