Electricity Use

[JohnW2]

test the usage on your freezer and FF .... old or faulty ones can be quite high users.

Indeed. A few years back I took an ancient freezer out of service since, although it was still working fine, it was consuming obscene amounts of electriity.

I am a bit surprised that your UFH only uses 0.70 kWh/day

That was my first impression, too - but at his 4h/day, that equates to 175W, which may well be credible for a "Warmup 2mtr UFH".

Kind Regards, John

 

[JP_]

That is a lot. Looks like you're averaging about 25.8kwh per day.
I currently use about 12 a day (was 11.25 on last count), and that is with 3 computers, 2 xboxes, and everything else that goes with a family of 4. Heating is gas.

The weather is getting warmer, so how about turn everything off overnight. Take a reading before bed, then another 8 hours later, with every socket off. Put a blanket over the fish tank if needed to keep it warm. Then do the same the following night with just the fish tank on. (I think a fridge/freezer should be OK 8 hours at night?)

Do you have a big house with loads of things on? In Feb I was using almost 15 units a day, but by stopping tumble dryer, electric kettle (boil on gas kettle now), and religiously turning off all sockets not in use, managed to drop by almost 4 units a day. Not a massive change, but will help.

Obvious check - is the immersion heater on? An electrician left mine on once after checking it was working when updating circuits. Was a few weeks before I spotted it!

 

[diynoob]

I used to use an Owl monitor that clamps to the electricity cables, it worked pretty well. Or there's the plug in meters that others suggested. Seems bonkers to pay for those these days though when you can get accurate 30 minute readings from a smart meter for free. Can you put pressure on your provider or switch providers to one that will fit a second generation smart meter?

 

[JP_]

A smart meter can only see total usage though, can't it?

About time somebody made a consumer unit with usage readings.

Actually, this thread just reminded me - on TV last night slow cookers were suggested as a more economical way to cook, than an electric oven. I love a good casserole or slow cooked curry. Might have to get one!

 

[ericmark]

I have three plug in meters, and I can monitor what any plug in item uses, I also have a couple of clamp on meters one hand held, the other the display can be monitored remote. However not sure they really help.

1) Light bulbs are marked with the wattage, so living room is 8 x 6 watt so 48 watt, so needs to run for 20 hours to use one unit the kWh. So simple to reduce usage can remove half the bulbs, but at 96p (working on 20p per kWh) is it really worth it?
2) Washing machine, tumble drier, now these are heavy power users, so wearing the same cloths two days on the run will cut costs, I tried to measure the cost of a wash, it was different every wash, the machine weighs the cloths, so even on the same cycle every time, each wash was different. We know by washing cooler or with less water we can reduce costs, and also not tumble drying, I tried not tumble drying, but by time I factored in how many time cloths were re-washed due to bird lime or other dirt, not sure it saves money putting cloths out on the line. Internet says cost to use per hour 30–75 p. As can be seen there can be a saving using the right machine. So random looked at Hotpoint NSWR 742U and it states "
Energy consumption per cycle 0.69 kWh" so 14p per wash, is it really worth worrying about?
3) Cooker, well here we can make a saving, the oven OK not much we can do there, but the hot plate idea is we want heat into the food not the kitchen, so the induction hob must help. But can't really use a 13 amp power meter, as hard wired, and we are looking at average, so to measure with main electricity meter every thing else needs turning off. But again per meal, hard to work out, clearly a meal using one ring cheaper than one using 4 rings or heat areas, but the rings be it halogen or induction switch on/off, so likely using a pressure cooker on an induction hob will reduce cost to using pans on a halogen hob, but still looking at pence saving.
4) Items on stand-by, be it TV or video recorder there is a 1 watt limit to most items, so 1000 hours costs 20p, there is an exception here however, satellite boxes can only monitor for program changes if the LNB is powered, so Sky box uses around 15 watt on stand-by, but even that is not much.
5) fridge/freezers, at last some thing worth monitoring, if the thermal insulation fails on a fridge/freezer it will use more power, also if it cools too much, I have a very small freezer bought for my mother, around 35 litre, the plug in energy monitor showed it was using around 75 watt when running, and 75 w/hour average. Clearly it was never turning off, this could be one of three, insulation failed, going to cold, loss of gas, so step one measure the temperature. Seemed easy until I tried to find a thermometer to measure -18°C, lucky I do home brew, and the thermostat used for home brew when that low, showed -24°C so new thermostat cured it. In the main fridge freezer uses 100 - 300 kWh/annum so less than £60 per year when running correctly, but one large one may use 1.5 times one half the size, so better with one big one than two small unless of course one fails. If not turning off, one can easy pay £500 per year instead of £60 per year, so well worth monitoring.
6) Immersion heater, this is an odd one out, 40 gallons takes a lot of cooling, so unless on a duel tariff, hardly worth switching off, what you want is loads of insulation around the tank. However I use a 1 kW under sink water heater, it stored 7 litres of water, and never seemed to run out, the insulation was very good, so likely saved energy.

However the big problem is to save electrical energy in the main means spending money, and if we are struggling to pay the electric bill, then too late, you no longer have the money to invest to reduce the bill.

I lived in a caravan for 3 years, with a 10 amp supply, all heating and cooking and rest all with 10 amp, to save money reduce rooms used to one. There is no magic cure, having unkempt hair and clapping hands to turn lights on/off only works with adverts, not in real life.

 

[ericmark]

So-
Fish tank is on an energy plug, it consumes 3.45KWH per 24 hour period / 95.2KWH in the last 30 days.
I have a server and high end IT equipment – my comms cab and all of the kit consumes 4.21KWH a day and 127KWH in the last 30 days

Well switch that off to start with.

I have 5x 4W LED soffit spots on for 5 hours a night
I have a Warmup 2mtr UFH set on 19C for 4 hours a day which is reporting 0.70 KWH A day / 37.37KWH per 30 days

The rest of the house is just usual family of 4 business - 10 year old American fridge freezer, Chest freezer, Samsung high end washer, Hotpoint dishwasher.

NO Immersions or form of electric heating other than aforementioned.

You need a fridge, so turn off chest freezer and store less food.

OK I have two fridge/freezers, chest freezer, upright freezer, and two fridges, but I can afford them. If you can't afford them, simple switch them off.

 

[JohnW2]

About time somebody made a consumer unit with usage readings.

kWh measuring modules are available for some CUs/DBs, but it would have to be a very large, and very expensive, CU if one wanted to monitor each circuit separately. However, since one usually knows (or can guess) which circuit(s) are responsible for the lion's share of total usage, I'm not sure that such a setup would tell one much that one didn't already know!

Actually, this thread just reminded me - on TV last night slow cookers were suggested as a more economical way to cook, than an electric oven.

I think one would have to do some very careful calculations, and probably some experiments, before being convinced about that. It's really all down to relative heat losses (which may not be truly wasted, at least in Winter, since they will heat the house), since the Laws of Physics dictate that any given amount of heat production will always require the same amount of electrical energy.

Kind Regards, John

 

[JP_]

I think one would have to do some very careful calculations, and probably some experiments, before being convinced about that. It's really all down to relative heat losses (which may not be truly wasted, at least in Winter, since they will heat the house), since the Laws of Physics dictate that any given amount of heat production will always require the same amount of electrical energy.

Yeah, that makes sense. For a casserole in an electric oven, I would guess that this is less efficient than a slow cooker, as you need to heat a big box with a pan in it. Maybe, like my gas hob kettle, better to do that.

I do like the idea of a slow cooker though. Less chance of burning what's on the bottom of the pot.

 

[big-all]

i have an old sony bravia 32" flat screen uses around 100w an hour
i choose to watch the still old but 32" samsung as it uses 44w
and the brand new 24"bush tv in the shed uses even better around 18w
changing the volume between 25-50% only made around 0.5w difference
all measured on low to medium light and volume
so worth checking what uses the least and watch that one the most

 

[JohnW2]

Yeah, that makes sense. For a casserole in an electric oven, I would guess that this is less efficient than a slow cooker, as you need to heat a big box with a pan in it.

Yes, that's what I was implying -although, as I said, at least in Winter the energy used to 'heat the big box' (beyond what was needed to heat the pan/food) is not totally lost/wasted, since it will eventually heat the room, and thereby reduce the amount of energy used by other methods of heating the room.

As I said, I think some careful calculations and experiments would be needed. The amount of heat loss (hence 'efficiency') is dependent on, amongst other things, time - and (unless it were unusually well-insulated) the slow cooker would be 'losing heat' (to the environment) for maybe 12+ hours, whereas the oven would only be doing so for perhaps an hour or two.

I do like the idea of a slow cooker though. Less chance of burning what's on the bottom of the pot.

True, but that's much more to do with temperature than the appliance being used. If you turned the oven temp down to just over 100°C (to be comparable with the slow cooker), you could use it as a 'slow cooker', and it's performance/'efficiency' might not be all that much different from that of an actual 'slow cooker' - particularly given that ovens are generally better insulated than slow cookers. However, people don't seem to do that, they usually do 'fast cooking' in an oven!

Kind Regards, John

 

[big-all]

i double fold a thick terry towel and lay it over the slow cook
you either need to reduce the cooking time by around 15-25% or turn the slow cook level down all by trial and effort

 

[Harry Bloomfield]

We know by washing cooler or with less water we can reduce costs, and also not tumble drying, I tried not tumble drying, but by time I factored in how many time cloths were re-washed due to bird lime or other dirt, not sure it saves money putting cloths out on the line.

You must be very unlucky with the bird lime and especially the dirt - I can't remember the last time that happened. We use the outside line of my .own design, when the weathers suitable - continuous loop of SS wire, round two pulleys, load/unload from one spot, counterbalanced so it has to be crank down from the house eaves. Indoors, in the utility I use a series of SS wires for hanging, with a fan to circulate air and a dehumidifier to dry the air. It dries two full washer loads in a just a few hours and so cheaply it can just be left running until next morning. The dryer is never used, but kept as backup.

 

[EFLImpudence]

i have an old sony bravia 32" flat screen uses around 100w an hour

No, Big-all. If it uses 100W then that is 100W all the time it is on.

If it is on for 10 hours that would be 1kWh - 20p?

 

[Harry Bloomfield]

i have an old sony bravia 32" flat screen uses around 100w an hour
i choose to watch the still old but 32" samsung as it uses 44w
and the brand new 24"bush tv in the shed uses even better around 18w
changing the volume between 25-50% only made around 0.5w difference
all measured on low to medium light and volume
so worth checking what uses the least and watch that one the most

Until a few years ago, our main most used TV was a 50" plasma, which used 350/ 400w. In my last economy drive I bought replacement Smart LED for it and relegated the plasma to the back bedroom as a spare/occasional use set, before then replacing the plasma completely with a Smart LCD. I have not tried it, but I suspect the insulation performance of garage and hut installed fridges and freezers could be improved by glueing polystyrene sheet to the sides.

 

[Harry Bloomfield]

In the main fridge freezer uses 100 - 300 kWh/annum so less than £60 per year when running correctly, but one large one may use 1.5 times one half the size, so better with one big one than two small unless of course one fails. If not turning off, one can easy pay £500 per year instead of £60 per year, so well worth monitoring.

Also aim to keep a fridge or freezer at near full all of the time, even if it is just filled with empty sealed boxes. The less the amount of cold air falls out of the fridge or freezer when you open it, the more you save - empty boxes help retain the cold air.