Electricity Bills over £400pcm!

MarkHudson14

This is a complex one so please bear with me....
We have an air source heat pump, underfloor heating and our 5 bed house was built in 2018. Our electricity used to cost about £80 pcm in summer and £180-£200 in winter. It now costs over £400pcm.
We've had a hot tub for the last 6 months so appreciate this costs an extra £15-20 per week but I can't account for the remaining £140 of electricity usage per month. We've had some separate meters fitted directly to the fuse box to monitor both the hot tub and air source consumption.
I have discovered that on average the air source uses 40kw per day, the hot tub uses 20kw per day and the remaining electricity used is 27kw per day. Based on electric being £0.155 per kw.
Any ideas?

tim_p

Are those figures (40, 20 & 27) backed up by meter readings that correlate with the bills??

Gerry1

Those figures are kWh, not kW.  It's important to understand the difference.

You seem to be paying more than is necessary: 15.5p/kWh probably isn't very competitive, especially if VAT is not included.

Do a meter sanity check: switch everything off at the consumer unit, watch the red LED marked 1000 Imp/kWh or similar for five minutes and make sure it never flashes once.  Then switch on a high power device such as a 3kW kettle or fan heater, count the number of flashes per minute and work out the actual consumption.

It's a bit rough and ready because the power drawn will be voltage dependent and the device will have a tolerance, but for 3kW expect 50 flashes per minute (pro rata if the meter shows 800 Imp/kWh or whatever).

You can also use this method to track down any circuits drawing more than expected power.

MWT

MarkHudson14 said:

I have discovered that on average the air source uses 40kw per day, the hot tub uses 20kw per day and the remaining electricity used is 27kw per day. Based on electric being £0.155 per kw.
Any ideas?

That seems to account for your £400 bill, so you are just not sure where the 27kWh is going each day?

The underfloor heating you mentioned could be a big part of that if it is electric?

Otherwise work your way around the other circuits using the technique Gerry described and see where the high use is happening...

niktheguru

Wish I could spend that amount of time in a hot tub each day! 

MWT

niktheguru said:

Wish I could spend that amount of time in a hot tub each day! 

Unfortunately it is often recommended to leave them turned on even if you are not using it everyday...

Mouldymeat3

Air source will grunt as the outside temperature falls. We have had a couple of cooler weeks this year and the performance of ours has had me looking at the compensation slope. I suspect the OP's system is more elaborate than ours and will have an extra in-line heater, controlled by the magic box, which cuts in on colder days.

MarkHudson14

tim_p said:

Are those figures (40, 20 & 27) backed up by meter readings that correlate with the bills??

Yes, I got really geeky with it and am physically taking meter readings every night and morning

MarkHudson14

Gerry1 said:

Those figures are kWh, not kW.  It's important to understand the difference.

You seem to be paying more than is necessary: 15.5p/kWh probably isn't very competitive, especially if VAT is not included.

Do a meter sanity check: switch everything off at the consumer unit, watch the red LED marked 1000 Imp/kWh or similar for five minutes and make sure it never flashes once.  Then switch on a high power device such as a 3kW kettle or fan heater, count the number of flashes per minute and work out the actual consumption.

It's a bit rough and ready because the power drawn will be voltage dependent and the device will have a tolerance, but for 3kW expect 50 flashes per minute (pro rata if the meter shows 800 Imp/kWh or whatever).

You can also use this method to track down any circuits drawing more than expected power.

Thanks Gerry. The rate has recently gone up from 13.3p to 15.5p in line with the rase in cap levels announced around the same time.
Yeah, I got similar advice and had the electricity shut off one night and the meter didn't record any usage. I also turn everything off one night apart from a 2000w space heater for 30 mins and it recorded it correctly.
I've also isolated usage from 11pm to 8am and subtracted the air source usage and I'm still using 7 units (£1.09) I've systematically turned off certain trip switches and found about a 50p saving if I switch off either downstairs or upstairs sockets.

MarkHudson14

MWT said:

MarkHudson14 said:

I have discovered that on average the air source uses 40kw per day, the hot tub uses 20kw per day and the remaining electricity used is 27kw per day. Based on electric being £0.155 per kw.
Any ideas?

That seems to account for your £400 bill, so you are just not sure where the 27kWh is going each day?

The underfloor heating you mentioned could be a big part of that if it is electric?

Otherwise work your way around the other circuits using the technique Gerry described and see where the high use is happening...

yes, exactly. I've eliminated the biggest usages of both the air source and hot tub and am still burning through 27kwh per day. I also checked and isolated the UFH but that only uses minimal electric for the pump.

MarkHudson14

niktheguru said:

Wish I could spend that amount of time in a hot tub each day! 

Lockdown purchase right there!