High electricity usage - what's the likely cause?

I’ve just switched a relative from E.On to Bulb - saving around £17 a month - (3p cheaper standing charge per day, 5p cheaper per day and 2p cheaper at night!) and realised they’ve got quite high usage compared to use (3 bed semi house, 2-3 “heavy duty” computers).

Their situation is:

  • 2 bedroom mid-floor flat (so flat on top and below)
  • Post-2000 build so should be reasonably insulated
  • Single person occupancy - but is occupied 95% of the time
  • Has “halogen spotlights” in kitchen and bathrooms, but aren’t used much (as enough light gets into the kitchen most of the time, and the bathroom is used for about 20 minutes a day)
  • Has low-energy bulbs in main rooms
  • Has dishwasher (used maybe once a day - sometimes just once a week)
  • Has washer/dryer (again, used maybe once a week)
  • Has electric oven and hobs - but only cooks 3 times a week (also has fridge/freezer)
  • Has a TV/Router/Soundbar combo which do get used a bit, but they won’t be massive power drainers. Also has an infrequently used laptop
  • Has Storage heaters (on Eco7) but very very rarely used as flat stays warm enough
  • Has a 210 litre electrically powered hot water cylinder for just themselves - it does power the used once a day shower, and the dishwasher/washing machine are all cold fed.

They are using around 400 units during the day/300 during the night (when the dishwasher/dryer are put on) - which is more than we use!

I would normally suggest doing the “take meter readings” test to try an isolate what could be consuming the power, but the electrical meters are in an entirely separate building and only the landlord has access to them and provides readings on a monthly basis (so there is a chance the entirely wrong meter is being read!)

My gut thought is the hot water tank is causing the high usage - but I didn’t make a note of it’s wattage, and surely it won’t use that much power would it? Any thoughts/comments on that?

Any other suggestions on what to check/investigate as to why their usage feels silly high (they should not be paying more in utility bills than we do!) given the lack of access to the meter?

could they use an energy monitoring plug to see how much each appliance is using? Measure one appliance for a day, note the reading, and move the plug to the next one?

a ‘non smart’ one such as: https://www.amazon.co.uk/KKmoon-Digital-Electricity-Electric-Monitoring-White/dp/B01GPUSOXI

or a smart one, if they’re into google/amazon/iftt: https://www.amazon.co.uk/Meross-Energy-Monitor-Control-Function/dp/B079D4RFXD

The obvious two are water heating and space heating. Have you also got an electrically powered water heater?

Heating 210 litres of water from 15c to 65c daily would use 350kWh+ per month. Granted, it’s unlikely all 210l would be heated from 15c to 65c each day…

Thanks - we’ve got a couple of energy monitoring plugs we can lend the relative: but their appliances are in-built/integrated so getting to the sockets will be tricky (especially with the size of the plugs) and I’d guess the other high users (lights, water boiler) will be ‘hard wired/on their own circuit’ so it’ll be difficult. Might be useful for the entertainment system though.

Any thoughts on the ‘clamp on’ meters - the meter tails do go into the flat (even though the meters are in a different building) and they do have their own circuit breakers in the flat, so I might be able to monitor individual circuits.

It is an electrically powered water heater (no gas at all) - but yes, the tank does feel like a highly likely cause (especially how little hot water is actually used). The ‘worse scenerios’ I can think of is an unused appliance behind a cupboard or something pulling power, it actually being a wrong meter being read or something like that.

“Any thoughts on the ‘clamp on’ meters - the meter tails do go into the flat (even though the meters are in a different building) and they do have their own circuit breakers in the flat, so I might be able to monitor individual circuits.”

They’re ok in this scenario, to give you a rough idea of instant usage. They need to know the voltage (which varies) to be more accurate.

I setup an old pi to run emoncms / emonpi, which provides fairly accurate usage info…

Hi Richy B. In case of interest I have had the same problem. I think I have found the cause but only time will tell. I have an electrically heated boiler. The plumber came around to fix something with it and tested the water temperature when taps are flowing hot only. He said the water was too hot and he turned the heating temperature for the boiler down. He said the first plumber who installed this should have done it. The way we tested was by putting our hands under the tap when it was just flowing hot. It was too hot to keep your hand under.

With hot water heating a major way that we use electricity I think this will probably save on my bills. Boilers are the main thing that consumer power. But essentially something like this is easy to test. Just see how hot a hot tap is in the morning.

Other things to reduce power consumption are expensive i.e. more energy efficient appliances. But this could be an easy way to reduce them if you had the same problem as me. I only got it fixed a week ago so I have yet to see if my bills come down.

Thanks, Andrew

there is a chance the entirely wrong meter is being read!
Don't you need to exclude this possibility first?

Some good tips here for analysing the issue :slight_smile:

Likely not the issue but just in case: we had an economy 7 water tank years ago, and realised our electricity bills were crazy high. It turned out the tank has two tanks - a larger one that was supposed to get topped up overnight by cheap eco7 leccy, then a small top-up tank for the day in case you ran low. It turned out the heating elements were switched by mistake - so the cost to heat the large water tank in daytime was extremely high, and only a small topup tank got heated overnight.

Aside from that doing regular readings through the day then comparing to usage may help identify if you can’t put metering plugs on devices.

In any case it might be a good idea to have a dual element immersion heater fitted to the cylinder so, if desired, only the top third is heated. A comfortable shower will only use about 60 litres so 210 is way more than the person needs to heat. Better still replace the cylinder with an 80 litre one.

As others have suggested an option is to use plugin energy monitoring plugs. Some of these are available with built-in displays others use a matching app.

However I did see your follow-on comment about integrated appliances.

Obviously the meter readings as displayed either on an old dumb meter or a new smart meter merely represent the usage of the entire house and do not help identify individual usage. This normally would also apply to ‘clamp on’ type sensors. However there are at least two brands of clamp on sensor that have added intelligence to ‘learn’ the energy usage pattern of individual appliances. In theory one of these solutions would provide a means of identifying the usage of individual appliances even those that are integrated and hence cannot use energy monitoring plugs.

See - https://www.smappee.com/
See also - https://sense.com/

Smappee are a European firm and have a UK version of their product. They also have Gas and Water sensors. Unfortunately currently their Gas sensor is not compatible with new Smart meters but does work with older dumb meters. Also unfortunately here in the UK whilst their water meter sensor would technically work the reality is that in the UK the majority of home water meters are located under the pavement just outside your property line and hence far too far away from your house and this also ignores the fact that most water companies would become very confused/upset if you tried this.

The Smappee Gas and Water sensors user either optical or magnetic sensors so in no way interfere with the meter nor require professional fitting. However as mentioned new smart (gas) meters are not supported by the Smappee sensors.

Sense are a US company. They are I believe interested in eventually supporting the European market but do not yet do so and their current product would not be compatible. I mention them because apparently their solution is both faster to learn your homes usage patterns and more accurate than Smappee. Perhaps if more UK/EU customers contact them expressing interest they will speed up their entry to the EU market.

Since Bulb have recently integrated with Smartthings I will also mention the fact that Smappee have some support also in Smartthings.

I’m confused here. Over what time period is the 400/300 units being used? Obviously it can’t be daily. Even for a month it’s quite high.