Electric Background Load

[Ian]

Back in Feb/March this year we completed our small (71sqm internal) single storey holiday home in Wales and I've been checking the meter regularly to record our electricity usage since then. It's been pretty steady at about 29kW per week.

 

We are only using the building at weekends and it seems to make very little difference to the overall power we use. I reckon our background electric load must be about 150 Watts per hour (IE the load when we are not there).

 

I was wondering if any of you have data on the background electric loads of your houses that you could share? Does 150 watts seem high to you?

 

I was surprised when I did a list of the various bits of kit that get left on all the time:

 

Burglar Alarm

Sewage Treatment Plant air blower (on 50% on a timer) Edit - this uses 2.7kW per week

Combi Boiler

WiFi + Hive thermostat controller (don't need this on now we're in the summer)

Nest smoke and CO alarm

Clocks on oven

Fridge

Various bits of kit on standby such as Dyson rechargeable vacuum, dishwasher, washing machine

 

 

 

 

Edited August 4, 2017 by Ian

[Jeremy Harris]

When you say "29kW per week", I'm guessing that's really 29kWh per week?  I'm also guessing that "150 Watts per hour" really means 150 W.

 

150 W background sounds about right for the loads you have on all the time.  The fridge and treatment plant blower will be the main culprits, with the combi boiler coming a close third, if it is set to come on for heating when you're not there, or has a DHW pre-heat mode.

 

The other stuff is trivial. probably no more than about 5 to 10 W in total, so not really worth worrying about.

 

You can probably get away with turning the fridge thermostat right down when you're not there, as the door won't be opening all the time and so it should stay cold enough on a lower setting - a bit of experimentation will show whether this works OK or not.  You could even just empty it and turn it off when you're not there.  Not only would that save energy but it would slightly reduce the fire risk - fridges can (very rarely) start fires, Grenfell Tower being the most recent high profile example.

 

You could make sure the combi isn't switched to a mode where it keeps hot, ready for instant hot water draw off.  Ours does this, which means it fires up every hour or so just so that the heat-up time when a tap is opened is reduced.  I turned this mode off, and frankly haven't noticed any difference at all in hot water performance, but it did stop the boiler firing up several times a day when it didn't need to.

 

Pretty much every appliance that doesn't have a battery-backed clock can be turned off when you're not there, too.  Probably won't make a big difference, though, for the level of hassle involved.

 

 

Edited August 4, 2017 by JSHarris

[Ian]

@JSHarris

Thanks Jeremy,

 

As you can tell, electrics is not my strong point!

 

Its good to know that 150 W sounds about right. Although it's only a small house it obviously has all the usual bits of kit that need an electric supply that bigger houses have so the size of the house isn't actually that relevant.

 

Ian

Edited August 4, 2017 by Ian

[TheMitchells]

That answer from Jeremy was interesting.  we are renovating and the house has hardly anything turned on when we are not there yet it still uses a surprising amount of electricity. As we have never been there during the night, I assume the fridge and combi are using the whole 60kW as that is all that's connected.  the charge for electricity for the 3 months was only £30 so I suppose £10 a month isnt too bad.  But having read the above, I think it is the combi boiler using the most - I can hear it come on regularly even when we arent using any water.  and its only the kitchen sink that uses any hot water at the moment as we haven't got the radiators or bathroom in yet.

 

Electricity readings Period Meter no.  22 Oct 16 to 23 Jan 17  Day 158  Night 60 kWh.

 

Does it sound too much and should I be turning off the 'ready and waiting' mode that Jeremy mentions?

 

The gas costs £18 for the three months and the only thing using gas is the boiler.  Again, I wonder if thats too much when we are using no heating and very little hot water.

[Jeremy Harris]

@Nickfromwales can give more info, but our combi defaults to a mode where it tries to keep the DHW side hot all the time, in order to reduce the warm up time when a hot tap is opened.  This is OK when you're in the house and using hot water regularly, but is a pain if you're not.  Finding how to turn this feature off may not be that easy.  For our Vaillant the feature is turned off by turning the DHW temperature control down to zero (fully anticlockwise) and then turning it back to the set temperature.  If there's a power cut, or the boiler is turned off and on again, it goes back to the default mode of preheating the DHW.  To turn the preheat mode on, then it's the same procedure, turn the DHW temperature control down to minimum and back up again.

 

Our combi has no easy way to tell when this mode has been set, or reset, as there isn't an indicator on the display for it.  I think you can go into diagnostic level 1 and scroll through the codes to see if it's on or off, but that's a bit of a faff.

 

My guess is that other makes may well have a similar feature, but will almost certainly have a different way to disable it.

[Nickfromwales]

@TheMitchells. What make and model boiler do you have?

[Nickfromwales]

13 minutes ago, JSHarris said:

Our combi has no easy way to tell when this mode has been set, or reset,

Same with you J, which model?

[TheMitchells]

a Viessmann 29kW combi boiler.

[SteamyTea]

Nick told me how to sort it out on a mates boiler (over on the old forum), it made a significant difference to my friend.

 

Now, statistics about energy, I am nearly wetting myself with excitement.

My house is all electric, so easy to monitor.  Here are a couple of energy density charts, one shows the probability at the 500W granulation, the other at the 25W granulation up to 500W (as that is where I use most energy.  The time period if from 12/02/2017 to0 14/05/2017.

The mean power draw is 409W, so an average of 9.8 kWh/day.

Each 'bin' is up to the next graduation i.e. 0 is 0W to 500W, 2000 is 2000W up to 2500W.

 

 

 

Edited August 4, 2017 by SteamyTea

[Jeremy Harris]

9 hours ago, Nickfromwales said:

Same with you J, which model?

 

It's a Vaillant Ecotec Plus 831, Nick.

 

Turning the top left DHW temp knob fully off, then back to the set temperature, turns the preheat thing on or off on ours.

[Nickfromwales]

1 hour ago, JSHarris said:

 

It's a Vaillant Ecotec Plus 831, Nick.

 

Turning the top left DHW temp knob fully off, then back to the set temperature, turns the preheat thing on or off on ours.

If yours has the dot matrix LCD display, then you should get an icon in the screen to show the state. I'll have a butchers at the MI's later . 

 

11 hours ago, TheMitchells said:

a Viessmann 29kW combi boiler.

Never fitted one lol. I'll have a look-see later but I will need the name / model number ?

[Jeremy Harris]

38 minutes ago, Nickfromwales said:

If yours has the dot matrix LCD display, then you should get an icon in the screen to show the state. I'll have a butchers at the MI's later .

 

Ours has what looks like a custom LCD, with graphics, rather than a dot matrix display.  AFAICS there's no indicator that lets you know whether the thing is set to the "keep hot" mode or not, but I have a feeling that you can see this in the level 1 diagnostics.

 

I did replace the main board in this boiler a few years ago, when a power surge following a power cut caused an odd fault with the original, where the boiler would lock on, even with no call for heat and with the level one diagnostics confirming there was no call for heat.  I lived with the fault for a while, as it only happened after a power cut, and the boiler could be reset by turning it off, leaving it for half an hour, then turning it back on again.

 

When I eventually got around to buying a new board, I made the gross error of asking on one of the plumbing forums about setting up the DSN, to programme the board for the Ecotec Plus 831.  I don't think I've ever had so much abuse from a load of job-protectionist prats in my life.  Luckily, one of the more sensible ones PM'd me the Vaillant DSN code list, so I found that our boiler needed to have the DSN set to 7.

 

If anyone wants to replace a Vaillant main board (DO NOT TOUCH THE GAS SIDE!!!) all you need to do is isolate the power, make sure the heating thermostat is not calling for heat and all hot taps are off, wait for any residual voltages on the board to discharge (a couple of minutes is plenty), take a photo of the board (to check later), disconnect all the plug in connectors, replace the board with the new one, replace all the connectors (use the photo to check if need be, although frankly it's pretty idiot proof), then power the boiler on.  Go to the diagnostics (warning - do not tell anyone on a plumbing forum you've dared to go into level 2, even though the user manual tells you how to.......), scroll through to d.76 and see what the DSN is.  If it's not set for your model, select d.97, increment to 17, go to d.93 and set it to the right DSN (7 for our model).  Exit the diagnostic mode and do a functional test, to make sure all is working OK.  Job done!

 

None of the above has any impact on the gas side, and the board is designed with so many safety interlocks that you cannot screw up - the worst that can happen is that the boiler won't work - it's designed to be fail-safe in the event of a main board problem, hence the reason that it is, in my view, perfectly legal to do this repair.  I'd definitely not suggest touching anything else in the boiler, but the main board is an easy thing to replace, more so because it's very accessible on a section that swings away from the main boiler very easily.

Edited August 5, 2017 by JSHarris

[TheMitchells]

9 hours ago, Nickfromwales said:

If yours has the dot matrix LCD display, then you should get an icon in the screen to show the state. I'll have a butchers at the MI's later . 

 

Never fitted one lol. I'll have a look-see later but I will need the name / model number ?

 will have a look next time I am at the house. 

[Nickfromwales]

36 minutes ago, TheMitchells said:

 will have a look next time I am at the house. 

?

[DavidFrancis]

Ian - I'm somewhat OTT on checking our energy consumption so can give you some of our figures (obtained from a plug-in monitor and by turning things on and off and checking our smart meter)

 

We have a combi boiler with a heat store (i.e. 60 litre built-in hot water tank) and the boiler fires up for about a minute several times a day to keep this store up to temperature.  It uses about 0.1 kWh/day in the summer and about 10 times this amount in the winter.

 

We have an old fridge freezer, the fridge of which is used for storing our drinks, and this uses about 0.7 kWh/day.

 

Our cooker seems to use about 4 W when not in use.

 

Our alarm uses about 10 W.

 

Our router seems to use 4-6 W.

 

We have a 39 inch tele and when turned off generally uses an un-registerable amount, but occasionally jumps to 40-50 W (don't know why).

 

All in all the two of us use about 4.5 kWh/day, but we don't have any halogen ceiling lights that are used regularly and our water/heating/hob are gas.  Your consumption does look a bit high to me.  Perhaps you could get a plug-in meter and check some of items you refer to.  Something like this (just an example, not a recommendation)

https://www.amazon.co.uk/d/Electrical/KKmoon-Digital-Energy-Monitor-Electricity-Electric-Monitoring/B01GPUSOXI/ref=sr_1_1?ie=UTF8&qid=1502208858&sr=8-1-spons&keywords=plug+in+meter&psc=1

 

 

[Ian]

@DavidFrancis

Thanks for that link to the meter. I'll give it a try.

(Edit - I worked out that if we were using the building full time we would be using about 5.2 kWh/day.)

At the end of last weekends visit I turned off the WiFi router and Hive box, the TV and the Dyson and I'll see if that makes any noticeable difference

Edited August 9, 2017 by Ian

[Iceverge]

I'm going to reach to the top shelf and pull down this dusty old tome of a thread. 

 

We recently spent about a week away. 

 

Before I left I tripped all the switches in the consumer unit except the MVHR, the blower for the bio cycle water treatment unit, the borehole pump and the fridge. 

 

Our average load of electricity was 245w since we left!!!!

 

To put that in context Thats over 2 MWh annually or about 2/3 of our annual heat demand. 

 

 

 

 

[SteamyTea]

8 hours ago, Iceverge said:

Our average load of electricity was 245w since we left!

The water treatment is probably most of that.

[Iceverge]

2 hours ago, SteamyTea said:

The water treatment is probably most of that.

 

Yup. I've turned it off for a while to see what happens. 

 

 

[Alan Ambrose]

There was some discussion on BH on this subject recently, we’re at about 190W background in our place. One way to delve into this further is to use a current clamp meter on the main incomer (one cable only, either line or neutral) and switch individual things on or off.

[Bramco]

So very roughly speaking around 5kWh per day.  We're about the same.  With solar PV, batteries and a tariff like Octopus Go intelligent (7.5p for 6 hours at night and 15p export), the marginal 6.5p we could earn by turning everything off is perhaps not worth the effort.

 

One thing we could do is to turn off all lighting circuits during the daytime - we have a number of smart devices to turn things on at dusk and off later on - but these only use a few of those background watts.  There's probably one out there but a way to manage this would be to have a wifi controlled circuit switch/RCD in the CU. That way we'd have just 3 or 4 of those loads rather than 10. But again, is it worth the hassle.

 

Simon

 

[NailBiter]

WiFi is a bit juicy. You would be much better off with Thread, Zigbee or BLE. I've got a few POE controlled relays that work well too.

[Jenki]

2 hours ago, Iceverge said:

 

Yup. I've turned it off for a while to see what happens. 

 

 

I had a cheap Chinese on off timer for a while, on 5 mins off 7 mins, but although it kept working became unreliable with the timer. Still looking for a better option ideally din rail mounted. I think the blower is 160w so a 60% ish reduction would be worthwhile.

 

[Alan Ambrose]

>>> Still looking for a better option ideally din rail mounted.

 

Take a look here:

 

https://uk.rs-online.com/web/c/relays-signal-conditioning/relays/timer-relays/?pn=1&applied-dimensions=4294883333,4292117068,4294571726&sortBy=P_breakPrice1&sortType=ASC

 

RS won't be the cheapest, but most of the stuff they sell is professional quality.

 

You'll probably need to apply a few more filter criteria, check the datasheet etc to make sure it has the continuous cycling function you want. In particular, check the contacts are man enough for the job ('max current') - suggest 3A min and beefier if you want long life.

[Bramco]

2 hours ago, NailBiter said:

WiFi is a bit juicy. You would be much better off with Thread, Zigbee or BLE. I've got a few POE controlled relays that work well too.

 

Agreed - we've got a mix of wifi and zigbee. Isn't the supply for POE a bit 'juicy'?

I wonder how these compare to a Loxone system?

 

Simon