Where is all our electricity going?
July 13, 2018 1:48 PM Subscribe
I just got our half year electricity bill (the first after moving into a new place) and it's higher than we expected. We used 10 kWh/day over the last half year. There is no A/C and centrally provided heating.. Please help me search the culprit..
The following things use electricity:
- Shower/hot water heated with a tankless water heater (about 30 minutes of warm water per day)
- A fairly new fridge
- All LED/flourescent bulb lighting
- One 12 V LED hanglight-construction that used to be run with Halogen-Lights (it s toroidal transformer could that for some reason be so inefficient powering LEDs).
- tea-water-kettle (maybe 10 Min/day).
- A TV that we usually shut down completely (there is a separate button that powers down the standby mode)
- Laptops and assorted chargers (no towers)
I'm planning on getting a plug-in electricity counter to go through all the individual devices one at a time but I'm a bit at a loss what could lead to this enormous toll.
All my earlier apartments had tankless water heaters and even though they use quite a bit of electricity even at 3 kW/h we'd need to take 3 hour showers every day to burn through this much electricity (same for the tea kettle and so on..)
Any ideas?
The following things use electricity:
- Shower/hot water heated with a tankless water heater (about 30 minutes of warm water per day)
- A fairly new fridge
- All LED/flourescent bulb lighting
- One 12 V LED hanglight-construction that used to be run with Halogen-Lights (it s toroidal transformer could that for some reason be so inefficient powering LEDs).
- tea-water-kettle (maybe 10 Min/day).
- A TV that we usually shut down completely (there is a separate button that powers down the standby mode)
- Laptops and assorted chargers (no towers)
I'm planning on getting a plug-in electricity counter to go through all the individual devices one at a time but I'm a bit at a loss what could lead to this enormous toll.
All my earlier apartments had tankless water heaters and even though they use quite a bit of electricity even at 3 kW/h we'd need to take 3 hour showers every day to burn through this much electricity (same for the tea kettle and so on..)
Any ideas?
Response by poster: Oops- the list is not complete yet:
Electric stove (avg. 10-15 min/day)
Washer (1/ week one load)
Dryer (once every two weeks)
Both washer and dryer are fairly new models
I have access to the meter - but I was also wondering if there was any way for the meter (one of the spinny ones/Ferraris to be faulty) - or electricity to leak in another way?
posted by mathiu at 2:03 PM on July 13, 2018
Electric stove (avg. 10-15 min/day)
Washer (1/ week one load)
Dryer (once every two weeks)
Both washer and dryer are fairly new models
I have access to the meter - but I was also wondering if there was any way for the meter (one of the spinny ones/Ferraris to be faulty) - or electricity to leak in another way?
posted by mathiu at 2:03 PM on July 13, 2018
I don't know your make and model of hot water heater, but the first result I found at Home Depot for a tankless electric water heater could use 9KwH/day (18kw for 30 minutes). I'd never heard of a tankless electric water heater before looking this up, but if you have one similar to this (others seem to be even higher wattage) I'd expect it to use a lot of power.
posted by jeffch at 2:09 PM on July 13, 2018 [2 favorites]
posted by jeffch at 2:09 PM on July 13, 2018 [2 favorites]
I recommend calling the power company to ask if your meter actually got read or if it was estimated from past usage. I had the same issue recently and my power company substantially reduced my bill because they overestimated my use.
posted by quiet coyote at 2:35 PM on July 13, 2018 [12 favorites]
posted by quiet coyote at 2:35 PM on July 13, 2018 [12 favorites]
Best answer: I’d double check the math on your tankless water heater. If you have cold water coming in the building you could use 3kWh in 15-30 minutes
posted by q*ben at 2:46 PM on July 13, 2018
posted by q*ben at 2:46 PM on July 13, 2018
Do you have a cable box? They sometimes use stupid amounts of electricity, even "off". Which is can be a fake off.
posted by TheAdamist at 3:42 PM on July 13, 2018
posted by TheAdamist at 3:42 PM on July 13, 2018
I know of a case where the mysterious power user was an electric baseboard unit in a bathroom.
posted by SemiSalt at 3:46 PM on July 13, 2018
posted by SemiSalt at 3:46 PM on July 13, 2018
The water heater. The dryer won't be helping either. Also seconding checking whether it was a read meter or an estimate.
Can you get more frequent bills, that will help you track seasonal variations, even if you only do it for a year or two (and reduce the 'sticker shock').
posted by GeeEmm at 5:44 PM on July 13, 2018
Can you get more frequent bills, that will help you track seasonal variations, even if you only do it for a year or two (and reduce the 'sticker shock').
posted by GeeEmm at 5:44 PM on July 13, 2018
You mention "centrally provided heating" which makes me think you're in a multi-unit building. Any chance there are other apartments or common area lights/appliances which might be tapped in to your electrical panel? Trying the "shut everything off and observe the meter" suggestion would be a good idea. Tankless HW heaters and electric dryers do use a ton of electricity, though.
posted by Larry David Syndrome at 5:48 PM on July 13, 2018 [1 favorite]
posted by Larry David Syndrome at 5:48 PM on July 13, 2018 [1 favorite]
Many libraries rent Kill A Watt power meters so you see exactly how much power a device is using when on vs on standby mode.
posted by peanut_mcgillicuty at 7:34 PM on July 13, 2018 [2 favorites]
posted by peanut_mcgillicuty at 7:34 PM on July 13, 2018 [2 favorites]
Best answer: Another vote for the water heater. My back-of-the-envelope thermodynamics comes up with about 2kWh to heat the water for an average 8-minute shower (heating 65 liters of water by 25-30 degrees celsius). And that's assuming perfect efficiency in converting electrical power into heated water.
posted by firechicago at 8:44 PM on July 13, 2018
posted by firechicago at 8:44 PM on July 13, 2018
Response by poster: So I spent some time on Wolframalpha - for the water-heater-calculations and buying some water-restricting perlators... I'll get back with the measurements :)
posted by mathiu at 3:33 AM on July 14, 2018
posted by mathiu at 3:33 AM on July 14, 2018
Usually tank-less water heaters are more efficient than tanked water heating systems. The heat loss due to thermal leakage, even with a well insulated tank and insulated pipes, is an ongoing expense. My money is on 'vampire' power drains like game consoles, cable boxes, anything that uses a wart style power supply, and forgetting to turn off the LED light thing. Consistent low-power drains add up and you never notice because you keep thinking that they just take so little juice to run. Also check the seals on your fridge and make sure that the temp settings are not maxed out. If you can make sure anything with an LED indicator that can be unplugged is unplugged.
As for the, "centrally provided heating," does that mean that you have no thermostat? If you have one there may be hidden things like the fans that move the heat into your apartment being on your circuit. Also given that this bill is for a six month period, did you supplement the heat in your apartment with anything like a space heater. That also brings to mind another question, what is the airflow around your refrigerator like?
And then the last question, do you or your SO work from home on a regular basis?
posted by Ignorantsavage at 11:26 PM on July 14, 2018
As for the, "centrally provided heating," does that mean that you have no thermostat? If you have one there may be hidden things like the fans that move the heat into your apartment being on your circuit. Also given that this bill is for a six month period, did you supplement the heat in your apartment with anything like a space heater. That also brings to mind another question, what is the airflow around your refrigerator like?
And then the last question, do you or your SO work from home on a regular basis?
posted by Ignorantsavage at 11:26 PM on July 14, 2018
Research shows that people tend to vastly underestimate the big-ticket energy uses, such as water heating for bathing and laundry. And they overestimate the smaller ones, like AC adaptors, which almost all draw a tiny fraction of a watt when idle. What kind of washer do you have? The older ones (top loaders) consume 150 liters of hot water, as much as a 20-minute shower. That's 4 kWh right there. It's also possible that you are sharing circuits with other units. Pick a time when other people are likely to be home and unplug everything. Your meter should come to a dead stop. If it's spinning merrily away, that could well be the problem.
But honestly your usage doesn't seem out of line to me. You're averaging 400W, which is about what we use with central air but a gas water heater. Heating water with electricity is incredibly inefficient, but it's cheaper for the landlord, so there you go.
posted by wnissen at 10:53 AM on July 16, 2018
But honestly your usage doesn't seem out of line to me. You're averaging 400W, which is about what we use with central air but a gas water heater. Heating water with electricity is incredibly inefficient, but it's cheaper for the landlord, so there you go.
posted by wnissen at 10:53 AM on July 16, 2018
This thread is closed to new comments.
Do you have access to your meter? You can shut off everything you see in the house, and check the meter to see if it's still spinning. Maybe there's something that's eating up electricity that you don't even realize is yours (outdoor lights for example).
posted by hydra77 at 1:55 PM on July 13, 2018 [4 favorites]