I’m spending a fortune running a heat pump in my build! Please HELP 😫

[damspt]

Model: Panasonic WH-MDC05J3E5  

Octopus Agile Tariff

 

Hi everyone, urgently need help as I can’t keep up with the costs at the moment🤦🏻‍♂️

I have attached some screenshots and pictures what might be important to know

My heat pump is in the back garden which is an open field after my fences

[damspt]

I’ve attached weather compensation curve and weekly timer!

[JohnMo]

Are you on the correct tariff would be my first question. If you have a battery maybe, without suspect not.

 

Do you have a timer for DHW or is that for CH as well?

[Bonner]

All depends on your insulation and air tightnesses levels but £6/day during this cold snap does not seem unreasonable, especially with 22/24 degree set points. My set points are 18/20 degrees but I do have a wood burner for the evenings. Do you have UFH, charging it when rates are low (overnight)?

[MikeGrahamT21]

What size, type is your property and how well insulated is it?

[JamesPa]

Its very cold at present, this is the time it will be at its most expensive (roughly double what you might normally see most of the season), Dont forget to factor that in!  With a cost of £6 presumably about 24kWh? - difficult to tell as you are apparently on agile (do you have a battery?  If not agile might not be the best tarrif)

 

For comparison Im currently consuming about 28kWh/day in a house with a loss of 7kW @ -2 and on the few days when its consistently sub zero I can consume as much as 50kW.  The heating is still cheaper and more comfortable than the gas boiler it replaced was, so Im not complaining!

 

You seem to have your WC set to 49@-2 and 39@20.  Does it need to be that high (answer no, certainly at the high OAT end)?  Are you operating 24x7 with WC adjusted and zones balanced, thermostats/trvs set to max so they have no effect or alternatively 2C above desired so they act as limiters?

 

Tell us a bit more and someone may be able to give some specific suggestions.

Edited Friday at 09:21 by JamesPa

[ProDave]

As above questions a LOT more information needed.

 

How old is the property? How big etc.  And your approximate location,

Is the Heat pump new?  Does it replace a previous heat source, e.g. a boiler, if so how much did that cost?

 

It is not easy to apportion heat pump consumption from a total electricity bill, I know exactly how much mine uses only because I chose to fit my own electricity meter to record just what the heat pump uses.  The best you can do is compare the daily usage now, with daily usage in the summer, if you do that you get an idea how much additional electricity is being used by the heat pump.

 

[Kelvin]

Cold here yesterday (below freezing all day) Heat pump consumed 11kWh of electricity but we have the temps set at 19.5°C. Very bright though so a bit of solar gain. 

[marshian]

27 minutes ago, JamesPa said:

Its very cold at present, this is the time it will be at its most expensive (roughly double what you might normally see most of the season), Dont forget to factor that in!  With a cost of £6 presumably about 24kWh?

 

For comparison Im currently consuming about 28kWh/day in a house with a loss of 7kW @ -2 and on the few days when its consistently sub zero I can consume as much as 50kW.  The heating is still cheaper and more comfortable than the gas boiler it replaced was, so Im not complaining!

 

Exactly this ^

 

Doesn't mater what heat source you are using the colder it is the more energy you will use to keep the house at a constant temp

 

Just over a week ago I was using 15kWh a day on "Space Heating" (OAT was Min 11.3 and Max 15.8)

 

Yesterday I used 70 kWh on "Space Heating" (OAT was Min -2.1 and Max 3.2)

 

Average for November will end up at ~30 kWh I see no point panicking about costs during a cold snap it's just part of the UK weather patterns

 

 

[canalsiderenovation]

4 hours ago, damspt said:

Model: Panasonic WH-MDC05J3E5  

Octopus Agile Tariff

 

Hi everyone, urgently need help as I can’t keep up with the costs at the moment🤦🏻‍♂️

I have attached some screenshots and pictures what might be important to know

My heat pump is in the back garden which is an open field after my fences

 

Is this all electric house, cooking etc all electric? We are using pretty much the same during this cold snap too but that's everything. We had temps down to -6 for 2 nights on the run though so very, very cold.

Edited Friday at 12:46 by canalsiderenovation

[Nickfromwales]

Are you using the heat pump to do hot water in this bitter cold snap? 
 

If so, your unit will hate you for it as it’ll be frosting and defrosting a bunch on low grade heat but will be much more of an efficiency killer when heating hot water. 
 

Try 48 hrs topping up with the immersion ( in off peak windows ) and see if that improves things. 
 

Also how long is the heat pump taking to recharge hot water? If it’s a long period then the house will start to cool down making the job of maintaining comfort temps even harder.

[Oz07]

Very topical... ill grab my popcorn 🍿 

[Beelbeebub]

Could the Op post the kwh usage graph from. Octopus. 

 

Thry say they are on agile which has a massive spike between 4-7pm (eg today 21st Nov it's neatly 50p/kwh)

 

Agile is for people with a battery (mostly) 

 

For a HP you need a Cosy tariff. 

[Dillsue]

Don't look at your eleccy usage for the very few days it's very cold as its normal to go through the roof when very cold. For the last 24hrs with it dropping to -2.5 overnight we used 54kwh but this our first winter with a HP so all a leaning curve.

 

WC settings have just been dropped a degree at each end as the wife is too hot:)

Edited Friday at 14:16 by Dillsue

[canalsiderenovation]

48 minutes ago, Beelbeebub said:

For a HP you need a Cosy tariff. 

 

We are on Cosy so heat hot water and UFH during those times. 

[JamesPa]

24 minutes ago, canalsiderenovation said:

 

We are on Cosy so heat hot water and UFH during those times. 

I have never understood how Cosy is a good fit to a heat pump unless you also have a battery.  Sure you get cheap leccy for a few hours per day, but at relatively poor COP because you are trying to get the same amount of energy into the UFH in one third of the time, so have to jack up the flow temperature (49C for UFH apparently, I'm running at only 43 on radiators).  Obviously you also need a heat pump which is a factor of 3 oversized. 

 

However, that notwithstanding (almost) everything above, is also true.  Its very cold at present so consumptio9n is at its max, (as it would be with any heating but who monitors gas or oil daily?)  If you have only just switched it on you have got a lot of making up to do.  It might be best to just monitor it for a few weeks and see how its averaging.  Also consider whether cosy plus jacked up flow temp is more cost effective than a different tariff plus running the UFH at a more typical 30-35C flow temp.  What COP is your heat pump reporting?

Edited Friday at 15:23 by JamesPa

[sharpener]

26 minutes ago, JamesPa said:

I have never understood how Cosy is a good fit to a heat pump unless you also have a battery. 

 

ATM it is exceptionally cold esp as it is still only November.

 

Normally you would have a lot of spare heating capacity for most of the year. You can use this in different ways, for instance to limit the output during the evening peak by using noise reduction mode or setback.

 

The difference between the 3 Cosy rates is I think much larger than the reduction in CoP

from restricting the output in this way part of the time.

 

 

Edited Friday at 15:45 by sharpener

[canalsiderenovation]

26 minutes ago, JamesPa said:

I have never understood how Cosy is a good fit to a heat pump unless you also have a battery.  Sure you get cheap leccy for a few hours per day, but at relatively poor COP because you are trying to get the same amount of energy into the UFH in one third of the time, so have to jack up the flow temperature (49C for UFH apparently, I'm running at only 43 on radiators).  Obviously you also need a heat pump which is a factor of 3 oversized. 

 

However, that notwithstanding (almost) everything above, is also true.  Its very cold at present so consumptio9n is at its max, (as it would be with any heating but who monitors gas or oil daily?)  If you have only just switched it on you have got a lot of making up to do.  It might be best to just monitor it for a few weeks and see how its averaging.  Also consider whether cosy plus jacked up flow temp is more cost effective than a different tariff plus running the UFH at a more typical 30-35C flow temp.  What COP is your heat pump reporting?

It works for us, three periods of cheap electric, 4am til 7am, 1pm to 3pm and 10pm til noon. We work from home and only heat the house those times although the stat is set at 18 degrees as a set temp we have it heated up more during Cosy so manages to retain the temps. Works for us...

[marshian]

31 minutes ago, JamesPa said:

(as it would be with any heating but who monitors gas or oil daily?)

 

I do - how on earth can you know if improvements are actually improvements otherwise 😉 

 

Octopus makes life easy from that perspective you can export by 30 min intervals your energy consumption - Add in HDD data and you have an instant bench mark for what ever set up you have 

[Oz07]

58 minutes ago, JamesPa said:

What COP is your heat pump reporting?

Good chance op doesn't even know what cop is...

[damspt]

Hi everyone, I’m trying to reply individually. I have contacted customer service and they are trying to help me out as for some reason I can’t reply to anyone. Below, i added a screenshot from yesterday’s kWh usage. And screenshots from today’s 8:30am when i wasn’t even home and a screenshot from 16:30 for a quick shower for my two year old son. 
 

I’ve noticed that it’s been since Monday (17/11) that we have been using a lot of electricity, I’m not sure if it’s a coincidence but our new fridge came on that day ( same as the previous one but had to be changed due to a fault ) 

My house is a new build that was build in 2024 and i moved in this year in February. It’s a 3 bedroom house 

[Nestor]

To reply to others type the @ symbol then a letter, names will pop up, scroll down to find the poster you wish to reply to.

Give it a try.

@damspt

[Beelbeebub]

Just for perspective our gas heating has shot up during this cold snap (shock!) 

 

We were sub 50kwh a day then the cold snap hit and we are more like 100kwh plus - and that's with a log burner going to take the edge off things. 

[Beelbeebub]

If you used 31kwh yesterday (20th) that's pretty good. 

 

The 20th was pretty cold (dunno where you are but it was sub zero across the Midlands). 

 

If we assume your house uses something like 6kwh a day for non heating stuff like fridges and lights, then you used 24kwh in a day, basically 1kw continuous heating load. 

 

If we assume a cop of about 2.5, that's a heat demand of around 2.5kwh. Not unreasonable for a house kept at 22-24C during a subs zero cold snap. 

 

If I read your graphs correctly on the 20th you used 31kwh and paid £6.52. That's 21p per kwh.

 

Coukd you post some pairs of graphs for the kwh in a given day, then the £for the same day.  I suspect you are losing out by using some energy during the agile peak period.  You could save a fair bit by making sure your hot water heating doesn't occur then and also maybe turning your heating off for those hours. 

 

Agile is best used with some sort of automatic system that adapts your use to the variable daily price curves. 

 

You migbt get a better price using Cosy. 

[JohnMo]

Not sure why you think the electric consumption is high. Assume you are all electric etc.

 

Our house seems to use about 20kWh without the heat pump.

 

 

Edited Friday at 17:46 by JohnMo