Large house, 3 phase electric but sky high bills! Help please?

Mrcsmrs

Evening all, 

Looking for some advice around electric only larger properties please? We bought a barn conversion two years ago, it has 10hkwh of solar panels on an outbuilding roof that we believe feeds back into the house. The house has underfloor air source heat pump systems, two systems in place to cover either end of the house. There’s an indoor pool that we only heat between May and September, and a small cottage annex that houses elderly parents. 

Our first electricity bill advised us that annual consumption was in excess of 58000 yes fifty eight thousand kwhs per year. We’re frugal with the heating, have only 5 of us living here, all adults, two working from home, two retired and a teen who’s at uni. We’ve reduced everything we could think to reduce but we are still apparently using over 45000kwh of electricity a year. We have an oil fired Aga which provides heat in one end of the house all winter, and at the other end a wood burner. We literally only heat the bedrooms, of which there are 3 in use in the house. The annex has oil fired heating and hot water so just powers lights and appliances with electricity. We cook on the Aga in winter. 

According to any supplier we contact we cannot change because we’d have to be on a commercial tariff, Utility Warehouse won’t change the meter or upgrade it to a smart meter because they have no contractors who work with 3 phase which apparently we have because we have so much solar. The solar brings in around £2000 a year. Our electricity usage seemingly doesn’t vary between winter and summer, whether the pool is running or not. We feel our meter is faulty but UW won’t change it because of the 3 phase thing and nobody else will take us on! Apparently we use as much electricity as a company with 250 employees! How can this be? 

House is 3500 square feet, converted 25 years ago, all double glazing. We cannot get anyone to tell us how the electrical systems in our house work, nor can we get anyone to work out if we are using any of the solar we generate. UW do not want to know, no local electricians want to touch it, and our electric bill is more than our mortgage. 

Anyone have any ideas how we can get this resolved, or what might be causing our issues? Or even if there’s a way we don’t know about to change supplier or deal with this 3 phase no smart meter issue please? 

Any suggestions gratefully received and thank you for reading this far. 

Jonboy_1984

Have you done any sort of sanity test, i.e. turned off everything at the internal consumer unit(fuseboard) and checked if the meter stops increasing. This is to rule out any remote farm equipment from still being connected.

Do you have any electric cars?

Have you looked at the watt ratings of the pool equipment, particularly any heating equipment as it is almost always generating heat that uses the most electricity.

45000kwh is in line with what we used in a 10,000 sq foot warehouse with most electricity going on old inefficient lighting.

Jonboy_1984

Further thought, you say the aga provides the hot water, do any hot water storage tanks have any backup electric elements fitted and if so are they definitely switched off?

Mrcsmrs

Jonboy_1984 said:

Have you done any sort of sanity test, i.e. turned off everything at the internal consumer unit(fuseboard) and checked if the meter stops increasing. This is to rule out any remote farm equipment from still being connected.

Do you have any electric cars?

Have you looked at the watt ratings of the pool equipment, particularly any heating equipment as it is almost always generating heat that uses the most electricity.

45000kwh is in line with what we used in a 10,000 sq foot warehouse with most electricity going on old inefficient lighting.

Ok, so we’ve had a scheduled power cut and the meter wasn’t increasing at this time, but other than that we’ve been a bit worried to just turn everything off because we don’t understand how most of it works. There’s no clear plan anywhere. 

No electric cars. The Aga doesn’t heat the water in the main house, just the annex. The water in the house is done by the air source heat pump system which is supposedly economic. That said we have the system at the living end of the house off other than heating the water maybe twice a week, with the bedroom end system running to heat water that end. 

The pool being on or off doesn’t seem to change our usage but I don’t know what the ratings are. I will ask husband to check it out. 

Thank you. 

Mrcsmrs

I should add there’s also several different fuse boxes, one at either end of our house, one in the annex which appears to be where the power comes into both properties, and another in the pool house. 

Robin9

Who is reading the meter ?   

A modern 3ph meter looks look a standard domestic single phase. To read mine I have to scroll down to get the IMP (Import screen)

Reed_Richards

When you bought the house you must have got an Energy Performance Certificate.  This will have had an estimate of the amount of power your house would use in a year.  What did that say?  The figures in EPCs are only estimates but if your heat pumps are working properly then the estimated energy use should be a good deal higher than your actual electricity use.  Although I'm not sure if EPCs take swimming pools into account.  

lohr500

With such a high usage figure it should be possible to identify the devices that are using the most electricity. The ASHP and pool heater must be the 1st places to look. Do you have monthly readings going back over say 12 months?

Heating the pool from cold in May would have used a lot of electricity until it got up to temperature. Do you know what volume of water it holds and what temperature it runs at?
Once up to temperature it should use less to maintain temperature. Do you have a thermal cover on it when not in use? If there is a lot of heat loss from the pool then that will be a likely source of high consumption. How does the pool heating work? Has the pool got its own heater or is it linked to the ASHP/s? Does the pool have a low temperature frost protection setting that may be set too high, causing it to run at a higher than needed temperature from September through to May?

The two ASHP could also be using a lot of electricity if not set up correctly. Do either/both have control panels that show the input energy.

The ASHP units may also be initiating a water heating cycle using immersion heater/s in the hot water storage tank/s to prevent legionella. This shouldn't account for a massive usage, but if programmed incorrectly the immersion heaters may be running too often or even continuously which isn't needed.

Lots of variables so I think you need to start focussing on the high usage areas and identifying the main culprit/s.

Those monthly meter readings I mentioned above would be really handy to try and see if there is a spike in May when the pool is 1st switched on.

QrizB

Excuse me being blunt but you have a large house, roughly 4x as big as the average 3 bed semi, including a swimming pool, and are using roughly 4x as much energy as the average house. There's nothing inherently absurd about your 50000 kWh/yr.

You say there's no clear plan of the electrical system. I suspect you could work it out yourself if you spent a day methodically going around switching circuits on and off and seeing what stops working. If you aren't comfortable doing this, it should be a simple job for a competent electrician.

Your main source of heat is two heat pumps. These do take a bit of getting used to if you've previously had conventional boilers. If you tell us the make and model someone might be able to give specific advice.

(Re. the swimming pool, heating water takes a lot of energy. If your pool is 10m x 5m x 1m, heating it by 1 degree C will take 60kWh.)

(Edited to correct some weird typos, due to me writing the post on my phone.)

Scot_39

Did the previous occupants not leave any documents for kit - like user manuals, maybe stamped with suppliers details etc  etc.

If not get kit models off of labels, power off of rating plates etc and search for them.  Badly configured ashp out of the box settings etc can be relatively inefficient.  Some types of compressor can also lead to so called vampire loads - in kWh Daily  -  in sumner when not regularly heating - as the compressors need to be kept hot. 

2 decent sized ashp would easily overwhelm a typical houses incoming single phase supply - which can apparently  be as low as 30A, 60A or 80A more typical, and max usually 100A. Even at 100A single phase  is only c23kW. 

For those more used to gas - that's less than the max for a small to medium sized domestic gas combi that could be rated 18kW HW, 24 kW GCH. Although these  often derate to as low as 6-10kWh and still don't run continuously.

You have lots of non standard kit.

But for a supplier to argue a 3 phase supply has to be commercial these days is kind of poor. 

Perhaps UW not the best choice - they arent even as I understand it energy specialists but multi service cross sellers. And cynically - its not in their interests to help you..

There have been posts here on MSE in past re upgrading to 3 phase to cope with move to ashp - specifically in fact to 2 ashp in larger properties.

45000kWh pa =123kWh daily is just over 5kW average power use day and night. At 30p that's getting on for £15,000pa.

And then you have the oil bills on top.

What was that Mirror Sunak home dig headline - £13k pa just to heat their pool ?

Did you mean 10kWp solar ? That's quite a large panel array for uk domestic - maybe 2-3 times average - but then so is your demand.  But even that might not be enough to match your peak demand.

Importing 5kW average on top of that - again extreme in summer.

Even the smallest small pool heater and pump rated say 2kW+, a small ashp 7-8kW, a larger domestic 10-12+ etc.

Are you being paid per kWh of export solar - or just the old nominal fraction of rated.  If former - its not impossible your metering could be wrong.  And you are paying for that too.  Literally just needs a reversed  current clamp according to another post here who found they were for few months.

As above ashp control systems might already give stats via displays or these days apps if have them etc to give clues.

Perhaps a local supplier of similar kit maybe willing to carry out a site survey - say ashp and say solar - and comment  - or give you a clue of someone - some sort of energy surveyor or consultant - who might.


Or you might want to invest in some  power monitoring kit.  Probably need clamp type for kit like ashp if cannot extract data from their controllers.

But you have a very large house - actually 2 houses of sorts - a swimming pool - another ? Outbuilding for the solar panels etc.  It's always going to cost a lost.  Perhaps you need to think about giving up such luxuries as a pool and a very large property if the bills problematic.

Edit : it's not like pre crisis prices are likely to return anytime soon - last CI 10 year graph showed a small decline, but nowhere near 2 years ago.

Keep_pedalling

I understand cold water swimming is big these days and also very good for your heath, stop heating the pool and you should see a big drop in use.