MrMagic

Your Home Base Load / Background Power Draw

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Posted (edited)

Hey all,

 

I was looking at power graphs for my home. I've killed or optimised most of the major loads already (A rated appliances, LED lighting everywhere etc) so I'm now starting to work through the background loads.

 

image.thumb.png.6e1dfbd2db73c74a060f12684d014d09.png

 

Heres an average overnight, with the A/C running. Minimum power draw was 183 watts.

 

I was wondering - what do other peoples homes draw overnight?

 

MM.

Edited by MrMagic

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Posted (edited)

7.2W for the Alarm

11W for the Wifi Routers etc.

0.5W for garge door opener

3W for the Microwave

1W for oven clock

5W for the TV/Virgin Media box

3W for the boiler (not running)

11W for outside light.

 

So total constant power consumption is: 41.7W

 

Then you need to add:

 

Intermittent 136W for the Chest Freezer

Intermittent 198W for the fridge/freezer

 

So it can be: 375.70W - chest freezer runs much less in winter (it is in the garage).

 

There are always some other little parasitic loads from chargers left plugged in etc. but generally it's not bad. This is about to increase with MVHR addition and a media server.

 

 

 

Edited by Carrerahill

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Ours is similar, around 150 W to 200 W.  The main culprits for us are the treatment plant air pump, the water UV disinfection unit and the fridge/freezer, not things I can reduce.

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about 150 W is our base load.

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Thanks all, so a range of 41 -> 200w.  41w is a tempting target..

 

Time to break out the meter plug and start hunting those watts! Will post back any major finds.

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Absolute base load about 125-150W, although rarely see that - one of the many fridges/freezers tend to kick in!

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This thread makes me feel not so bad.

 

I am using about 80KWh per week on "stuff" which is basically everything except space heating and hot water.

 

That averages to a constant load of 470W but remember that also includes the washing machine, dishwasher, tumble dryer, tv;s etc.

 

I have yet to analyse the true unavoidable background load, but might have a better idea in 2 weeks.

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Posted (edited)

My major loads are at night, but if I look at the fraction of time that I am drawing up to 10W, it is, between 28/06/2019 and 07/07/2019 (last week) 0.6, so 60% of the time.

10W up to 20W is 0.01, 1% of the time.

So that is basically the radio, laptop and fridge, toilet MVHR unit.

If I look at the same time period, but bin the data into 1kW chunks, then 0W up to 1000W is 0.92, 92% of the time.

1000W up to 2000W is 0.004, so less than 0.5%

2000W to 3000W is 0.05, so 5% (probably kettle and cooking and maybe washing machine)

3000W plus is 0.021, so water heating is around 2% of the time.

 

I need to work on my sub 1000W loads, but mainly below 50W as that accounts for 72% of the time.

Radio is 3W, laptop 8W, fridge, on average 5W.

But when I look at the numbers at 1W resolution, 60% is between 0 and up to 1W.

So I am not going to worry.

60% of the time I use no power at all, I should ask for a reduced meter rental.

Edited by SteamyTea

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I have unplugged my stereo as reading this I noticed the standby light permanently lit but rarely used! I too have fridge/freezer, MVHR, and treatment plant, my PVR is always on to record those programmes I forget to watch at the time.

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Posted (edited)
11 minutes ago, joe90 said:

I have unplugged my stereo as reading this I noticed the standby light permanently lit but rarely used!

Just pulling up your data now.

 

Here it is, big loads first, then the little ones.

 

0 to 10kW J90.jpg

0-100W J90.jpg

0 to 10W J90.jpg

Edited by SteamyTea
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Posted (edited)

Between 20 and 30 watts when the fridge is off, about 80 watts when it's running.

 

It used to be a bit less, about 15 to 20 watts, when the fridge was not running. I've recently added a Sonoff TH16 switch with temperature sensor to override the thermostat in the fridge as that was freezing the contents of the salad tray. Bit (small bit) worried that that's accounting for the extra watts which would be annoying. More investigation required.

 

p.png

Edited by Ed Davies

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On 12/07/2019 at 15:02, Ed Davies said:

Between 20 and 30 watts when the fridge is off, about 80 watts when it's running.

 

It used to be a bit less, about 15 to 20 watts, when the fridge was not running. I've recently added a Sonoff TH16 switch with temperature sensor to override the thermostat in the fridge as that was freezing the contents of the salad tray. Bit (small bit) worried that that's accounting for the extra watts which would be annoying. More investigation required.

 

p.png

Could be that your evaporator coils or fan are clogged up with dust. Try cleaning them to see if the consumption drops 

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1 hour ago, Miek said:

Could be that your evaporator coils or fan are clogged up with dust. Try cleaning them to see if the consumption drops 

 

It's possible that a clean round the back of the fridge would help with whatever's causing the problem with the fridge freezing the contents of the salad tray but I doubt it's the main problem. It happened a bit last summer but is worse this year. What I think is happening is that the thermostat is right at the top of the fridge and the insulation is probably not that great by modern standards (only A+) so when the temperature in the kitchen is reasonably high it makes the fridge run too long. A previous fridge I used had a switch for warmer/cooler outside operation but I can't see one on this one, either in the actual fridge or in the manual.

 

BUT, the extra consumption I was referring to, the step up from below 20 watts to above, is during the time the fridge is not running. Any problem with the evaporator on the fridge might affect the consumption when the fridge is running or the length of time it runs (so the overall overnight average, which is about 45 W, BTW) but not the fridge-off total consumption. That means with the Sonoff is drawing about 5 W or so when it's idle, which seems a lot, or there's another phantom load plugging in somewhere that I've forgotten about.

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When the compressor if off the fridge could still have fans running, internally to circulate cold air and externally on overrun to clear the heat from the condenser side. Depends on you fridge i guess.. 

 

My washing machine draws 10w to do nothing! Crazy wasteful IMO 

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1 hour ago, Ed Davies said:

What I think is happening is that the thermostat is right at the top of the fridge and the insulation is probably not that great by modern standards (only A+) so when the temperature in the kitchen is reasonably high it makes the fridge run too long. 

 

Can you not turn the fridge down a notch?

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I had a fridge that was consistently freezing stuff.  Within a year it was running constantly but not cooling.

I picked the extra electrical usage up on my energy monitor, so was only 3 days of wasted electricity and milk.

So could be something as simple as a refrigerant gas leak.

Might be worth putting a temp sensor on the back of the fridge (or where it dispels the energy) and seeing what is happening there.  I noticed, in hindsight, that it was not warm.

 

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Posted (edited)

Just as an aside, when I first started monitoring energy, I used an old desktop computer, it was drawing about 200W.

I have some little USB energy monitors now, so shall plug on in and see what my Raspberry Pi Zero is drawing.  It is reading 7 1Wire temp sensors every minute and logging the data.

Seems to be about 0.55W (4.9V and 0.2A).

If someone reminds me, I shall look at the Wh reading next week to get a better idea of what is happening.

12:15 PM 14/07/2019

 

Edited by SteamyTea

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What is the best (cheapest) way to measure consumption from individual sources (for a Luddite who does not have raspberries 😂)

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12 minutes ago, joe90 said:

What is the best (cheapest) way to measure consumption from individual sources (for a Luddite who does not have raspberries 😂)

 

One of the plug-in meters would do the job, perhaps like this one: https://www.screwfix.com/p/energenie-ener007-energy-saving-power-meter-socket/3477h or one of these: https://www.amazon.co.uk/plug-energy-meter/s?k=plug+in+energy+meter

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This inspired me to work through the house and figure out where our 250W base load is spent. Just used the smart meter display.

 

Top culprits (ignoring fridge/freezer):

70W on internet router/switch/modem/wifi APs

60W on 2x PCs (expected)

50W on a home theatre amp even in standby

16W TV on standby
The rest mostly distributed among numerous small electrical items & chargers.

 

The Unifi router & PoE switch are SOHO/business grade, with big ol noisy fans, so not surprised they come out high but still makes me wish I'd thought to research that more before going all in with their gear.

I must think again about having always-on Windows PC;  the linux one is inevitable.

The home-theater amp is the most  disappointing, given it's a fairly new model, Sony STR-DN1080, and 50W is crazy for just sitting there doing nothing. The obvious thing would be to use a slave switch to power it right down when the TV is off, but it'd defeat one of the main reasons I went for that model (built in Chromecast for multiroom music streaming).

 

Anyway, certainly some savings can be made.

 

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If you need an always-on PC, then there are some very low power, passively cooled ones about.  We have two of these, one with a Core i7-7500U, one with a Core i7-8550U.  Both sit at around 7 W most of the time, less than 1 W on standby, and never more than 15 W.  One has 8Gb of RAM, the other 16Gb, and both are fitted with Samsung Evo SSDs.  Although the Core i7-8550U is supposedly about twice as fast as the Core i7-7550U I can't say I've seen any difference at all between them.

 

As these machines have turned out to be reliable, low power and have reasonable performance, I've been thinking about buying one of the same companies multiple Gigabit Ethernet port machines as a firewall/router.  The company is Hystou, in China, and their basic kit seems very good, although best to get a barebones machine and fit decent RAM, SSD etc.  Also their WiFi cards are not great, but I removed these and blanked the antenna holes, as we have no need of WiFi, and removing the WiFi card reduces the power very slightly.

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6 hours ago, joe90 said:

Can you not turn the fridge down a notch?

 

Yep, that's what I did last year and earlier this year. Reached the end of the scale.

 

7 hours ago, Miek said:

When the compressor if off the fridge could still have fans running, internally to circulate cold air and externally on overrun to clear the heat from the condenser side. Depends on you fridge i guess.. 

 

In this case the Sonoff TH16 has turned the fridge off externally so it can't be doing that. Not even the internal light works when it's off. Still, I was fairly confident it didn't do that before I added the Sonoff (otherwise I'd have been a bit more circumspect about just switching it externally) because it turned on and off so cleanly as seen by my energy logging.

 

BTW, the Sonoff is running my own code, not the standard internet connected stuff. I have some code to not turn the fridge on or off too often (run for at least 10 minutes and be off for at least 6 minutes, IIRC) on top of the hysteresis implemented for the temperature.

 

6 hours ago, SteamyTea said:

I had a fridge that was consistently freezing stuff.  Within a year it was running constantly but not cooling.

 

Interesting, I wonder how that happens.

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likely first a faulty thermostat which caused the compressor to overwork and subsequently die...

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On 14/07/2019 at 18:43, dpmiller said:

likely first a faulty thermostat which caused the compressor to overwork and subsequently die...

 

My thought too. I can't see how anything other than a faulty thermostat would cause excess freezing.

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