I'm happy with my running costs but not the cost of electricity. My annual costs below are based on year-end on the 1st of May. They are self explanetary.

Annual Usage:

Heatpump Kwh 3851

Electricity Kwh 5555

Oil 1800 liters**

Solar Generated Kwh 3488 (approx 50% used)

Costs at current prices are 0.265p/kwh

Oil price  at current price £1980**

Current HP £1020

Electricity total £1472 FIT not deducted

The annual daily charge for elec £150

**HP replaced the oil boiler.

I am certainly concerned, mainly because our future electricity price is an unknown quantity.  We're currently on a fixed 20p/kWh until 02/10/22, with a 20p daily charge.  I am expecting this to probably double, which is quite a scary prospect.  Our energy bills have reduced by ~£40 per month since switching from LPG boiler to ASHP (that includes an increase in electricity from 15p to 20p/kWh), but that gain is obviously going to be wiped out, and then some!

Since installing the ASHP we have also fitted a log burner in our lounge.  That was originally just for aesthetic reasons, but I can now see us turning down the ASHP compared to last winter and using the log burner a lot, not to mention adding some extra layers!  Another change we are thinking of making in the near future is to replace the wooden flooring that currently covers our underfloor heating with porcelain tiles, that should make the ASHP heating of the ground floor considerably more efficient.

Yes, but it's going to hurt.  Lower temperatures, more coal/wood burnt and extra layers I think.  In relative terms, it's worse for gas CH homes; not sure about oil.    

We are still on old fashion mains gas rather than a heat pump as you know. 

The unit price of mains gas has actually increased faster than the unit price of electricity so the challenges are not limited to heat pump owners.  Heat is a general issue i think. 

Our unit price of electricity is still 3.85 the unit price of gas on our current variable tariff so i can see the basic challenge of ashp affordability in winter without making other changes. 

Our annual usage over the last year has been a bit below the typical consumption values of 2900 electricity and 12000 gas units. We were on a relatively cheap rate and our annual bill came to £889.95 when i just looked including standing charges and VAT. 

We are now on the standard variable rate. I am assuming we might have a colder winter as this year was relatively mild, so budgeting the £2800 a year the same figure as the Oct price cap estimate for typical consumption is a good rough estimate for us. It is a big percentage increase but affordable in our case currently. 

I can imagine some people on relatively fixed incomes really struggling to find another circa £2000. They may have been coping quite well before but really don't have that much spare income. 

We are not planning on making any major changes to our current home as we are planning to move in a few years once my partner retires early hopefully. Any changes are better left to the next owners as it will need significant changes to incorporate a heat pump. I am realistic this may impact the price we can sell the house for in a few years. 

i  completely understand that run costs are now much more important than they were a few months ago. Ive been doing some work on this working out the best way to get the cheapest run cost from your heat pump. I dont want to spoil the report but its MUCH cheaper to run a heat pump all the time, never change the set temperature, never let the house temperature dip.  heat pumps liek to drip feed heat into the house. 

I run mine 24/7 from September until April every year, In summer i turn the heating off, i cant bear the thought of the heating running in August even if the weather is awful. My heat pump never stops and i NEVER adjust any stats. 

in a  week or two i will be blogging with the results. 

Posted by: @grahamh

i  completely understand that run costs are now much more important than they were a few months ago. Ive been doing some work on this working out the best way to get the cheapest run cost from your heat pump. I dont want to spoil the report but its MUCH cheaper to run a heat pump all the time, never change the set temperature, never let the house temperature dip.  heat pumps liek to drip feed heat into the house. 

I run mine 24/7 from September until April every year, In summer i turn the heating off, i cant bear the thought of the heating running in August even if the weather is awful. My heat pump never stops and i NEVER adjust any stats. 

in a  week or two i will be blogging with the results. 

Looking forward to the blog. 

Am curious on your thoughts on Time of Use tariffs and heat pumps. The delta in costs in 30min electricity slots can be so dramatic, potentially dwarfing any delta in COP rates by running the actual heat pump less efficiently.

Octopus looked at 1000 customers who had heat pumps. Given that Time of Use tariffs may become the norm, do we need more intelligent heat pump controllers? What about the role of batteries? 

Customers on their Agile Octopus tariff, who programmed their heat pump to run more in off-peak periods (when power is greener and cheaper) were able to reduce their energy costs by around 20% vs a flat rate tariff. Of course that may be difficult with the current situation with electric pricing. 

Our gas costs have gone from £880/year to double that now that gas is 7.9p/kWh (yes, we're on the back stop rates)...

My numbers, based on using 17257kWh of gas last 12 months:

In our current non-condensing baxi back boiler on a Y plan, assuming 75% efficiency:

17257*0.75 = 12942 kWh of heat energy delivered to the property.

To generate that with an ASHP with an SCOP of 3.5:

12942/3.5 = 3697kWh of electricity required, at current prices for the year - 3697 * 0.28 = £1035.42

Compared to buying 17257kWh of natural gas at the new rate of 7.9p/kWh = 17257*0.079 = £1363.30

So, a £330 saving per annum (not including the gas standing charge, which can go as we cook on electricity). Obviously there is the capital investment, but the boiler dates from the mid 80's and the rads are all in need of replacement anyway, so that needs to be done regardless.

So, TL;DR, I'm not worried about the rising costs of electricity, I'm more concerned about the rising costs of gas. I should be installing my ASHP before this winter comes... Will I be able to afford to keep the heating on, yes... I work hard and we don't have a mortgage or kids to pay for.

@grahamh Have you considered ditching the room stat and jumpering out the call for heat input, just relying on weather comp to keep the house at your preferred temperature?

@grahamh Looking forward to your report. I use my HP Samsung 12kw Gen 6 on a thermostat which has given me good performance. I am keen to try using the weather compensation so your report will make good reading and many questions.

@prjohn you could be n ideal candidate for a technology i use at home which is used on Samsung units . keep an eye out for my blog, it will be a couple of weeks. 

A hughf, its a nice idea and its pretty good but its not the best way. i will leave you in suspense blog will follow soon