I have a 300 litre hot water tank, electric, and on average the control load consumption is 40 kilowatt hours a day, which seems high?
How big is everyone else's control load consumption?
Hot Water Heater Power Usage
deme on 07/07/2024 - 19:50
Comments
Sydney
I have a 320L tank, last bill was 12kw average.
Last winter was 14.35kw. Sydney also but tank in garage
Ive got a 250L tank on offpeak - Controlled load 1 and using about 3.5kW/day but its only me.
Comes to about 311Kw per qtr.
And I mostly take hot showers after my daily swim and only need to do 2 loads of (warm water) washing per week.
I guess Im luckyFrom OP's perspective they need to consider and compare:
-Number of people in household taking hot showers and/or baths each day, how many and for how long!
-How many loads of washing per day/week using warm or hot water.
-Dishwasher - how many times per day is this used
-Any leaking taps?
-Does anyone leave the hot water running?
-Does OPs HWS have 1 or 2 power connections - some top up the hot water during the morning as well as doing a full reheat each night - so will cost more to run.A hint of high usage or a significant leak would be if OP is running out of hot water!!!!
So OP cannot compare Hot water Kilowatts with anyone else.
One needs to be an exact fit with OPs household use of hot water
But yes, seems a bit high to me
@HeWhoKnows: Great data point, thanks.
I live in an apartment with centralised water heating, and the bill is about ~$80/qt for hot water including daily supply charge.
Just me living here, and it's mostly the shower that uses hot water as the rest of my appliances do their own water heating.I've been wondering the what having a heater would cost.
Sydney you should expect about 16kwh a day right now, yours is very high so likely you're having a leak.
Depends on how much hot water you are using.
Just checked my last bill and controlled load meter dedicated to our 300l electric storage hws used 130.27 kWh over 32 days. Our hws is in the garage so not completely exposed to the elements but we have pretty cold winter nights where we live.
What is your hws thermomstat set to?
What is your hws thermomstat set to?
How would I check? What does the thermostat look like? There was nothing I could see that was obvious.
You will have to remove the small service door. Inside will be something similar to this
Ours is set to 62°c. The minimum safe temp is 60.
Thanks, I'll check tomorrow and report back.
@deme: Well I might not be available to help further tomorrow. I'll make an exception for you though on this occasion.
If yours doesn't have the fancy numbers (the same as mine) you can simply turn on a hot water faucet (kitchen sink is a good one) and put a meat thermometer under it (or just regular if you're game).
Years ago I had my gas hws replaced and the installer set the temp to max, only realized after bill shock
What's the faucet mate?
your suggestion only works if there's no tempering valve, if the system was installed within the last 10 years or so it won't show the true temperature of the tank.@lgacb08: Where the water comes out into your sink. Probably could have worded that better "hot water tap at the kitchen sink faucet" early morning brainfart.
That may be the case, but you don't want the tank at 60c; you want the water in your kitchen sink/dishwasher to at least be 60c? Could have temp loss just from the pipes.
@lgacb08: Idk man but these Americanism's are starting to get irritating. Just had a fight with some supposed Aussie who was adamant that "trash" was some colloquial thing. Probably a teen who grew up with American media.
Check your relief valve, could be leaking. Feel if the overflow line is hot.
For comparison - we have 3 people and 160l heater set to 70 degrees in SEQ area and it consumes between 6-9kWh per day on average.
https://www.endeavourenergy.com.au/your-energy/how-to-save-e…
40 kWh is way too high regardless. Should be under 20 at very most.
if your system is running at 40kwh a day and average energy cost is 33.84c/kWh - then that system is costing you $13.50 a day to run. $94.50 a week.
check that all the taps are turned off in your house and go check your water meter to see if there is a turning over as you may have a leak.
I have a roof top solarhart system which I never attached to power when I installed it and it costs me $0 a year to run.
how does it work in winter? Still enough sun?
works fine. if there are 3 days of pure cloud/rain then the hot water will run out (4 people in the house).
that has only happened twice.
it only needs ~1 hour of sun to heat the water.
5 years of free hot water, so far.
Pure electric hot water is a wallet killer. Upgrade to Heat Pump. There are some programs in VIC, pretty sure NSW will have something similar. 40 kWh per day is painful. With heatpump you will probably get away with 2-3kWh tops.
NSW program will cost upward of 2k to install a new heat pump system. I’m currently looking into this.
Literally going through this process in SA right now. It's possible to get a heat pump installed for somewhere between $0 and $300 depending on the option (or was a couple of years ago when I first looked into this), but it's not really advisable. They are crap, don't last very long, and then when they break, you've used up your STC credits on them. So you're better off long term installing something that's going to last better, even if it costs $2-5k.
Looking at the most efficient one currently and some of them give you the option of installing it inside instead of outside.
The compressor should go outside and the unit can stay inside I assume?
Anyone has any idea?
@spc12go: Reclaim or Sanden? Yeah I think the compressor needs to be outside (or it needs a certain amount of space around it). Not a plumber or installer though, so not really sure.
@spc12go: You need a heat pump with a separate compressor, which is only the more expensive ones. The tank can go whereever; the compressor needs to outside. I am not sure of the max distance between them but certainly a few metres (Sanden I think allows 15m max but others its 3-4m and the closer the better)
There is no real benefit in having the tank inside but if it suits your space then obviously go for it
@spc12go: Integrated vs separate
Benefit - cheaper
Downside - have to replace the whole unit if the pump breaks. Smaller compressor is quite a bit less efficient. May require electrical booster. Noisier. Compressor is higher up so can be closer to windows.
should be less than that - I just googled https://www.efficientenergygroup.com.au/hot-water-systems/
there are two options: go for cheap ass option like Midea and Reclaim for under 1k or more expensive 3-4k that will last longer.
If you’re running a CL system to heat hot water, do you need to switch over to regular circuit if installing a heat pump? I’m guessing that heat pumps should heat up “on demand” hence only having controlled load overnight is no good.
Would mean an upgrade to the meter I suppose.
Any tips?
When we moved into our house, we found the previous owner had installed a hot water recirculation system where a small pump circulates the water constantly so that you have instant hot water at any tap at any time - nice to have but crazy expensive! We disconnected it within a month when we realised what was going on - the pump was very quiet so we didn't initially understand why the power bill was so high when there was only 2 of us!. Was using around 40kW..
Username checks out
We have a 400L 3.6kw tank and use about 11kw a day in winter (Brisbane). This is mainly for 3 x showers (<5 mins), and a bit in the kitchen for washing up pans in the evening.
As previously suggested, definitely check the overflow pipe. This is a common cause of big bills. Most water heaters have a relief valve which feeds the overflow pipe. These valves have a limited life.
I'm troubleshooting a similar problem right now. We have a Rheemglas 160L electric storage system for 2 people who don't take too long showers I think. It was using about 15kW per day. It's 20 years old so well into EOL but I'd like to fix it if possible.
I disconnected and flushed it, there was ~6 inches of sediment built up on the bottom that had totally encased the heating element. After I got all that out and cleaned up the element (which wasn't corroded, just covered in calcium? deposits) our usage dropped to ~10kW per day. You're supposed to flush them once a year or so, I don't think mine had ever been done.
I still thank that is a little high though. After one person's shower the unit tends to run for ~2 hours. So it could be the thermostat sensor which I will try replacing next.
You are wasting money having an electric element heating your hot water, as even when not using hot water you are keeping it hot against the elements, the insulation on old hot water service is very poor and the thermostats are not very accurate as they are usually mechanical, you would be much better changing this to the newer heat pump units you would use much less electricity.
Exactly right. Or use natural gas.
What else is wired to it?
I have no idea about other areas, but in Brisbane we can have freezer, pool pumps, a/c etc. hard wired into the controlled tariffFamily of 4 taking showers & washing dishes with a 300l tank
Usage winter 12kW, summer 10kWI just turn mine off after showering.
Isn't it considered dangerous to let your hot water system drop below a certain temperature? ie. legionnaires' disease. I mean, if you had an instant hot water gas/electric system it might be different.
I think it's fine for it to drop in temperature, but what's important is that you're regularly heating it up to the threshold needed to kill bacteria. My installer said as long as it does this at least every couple of days then it's safe.
I have solar HW rooftop storage with instant electric for boosting. I have an analogue timer that only heats the water from 4pm to 8pm after the solar HW has had a decent run during the day, so it doesn't have to boost much on some days. My family only takes showers in the evening.
How have you determined the consumption of the unit?
My steps would be:
1. Check for leaks at the water tank
2. Make sure all water using systems in the house are off.
3. Go to the water meter to make sure its not counting up.
4. Call a plumberI have a 250L, 4.5kw off peak water heater on Controlled Load 1, mounted outside but under cover. It heats each night about 11pm until the thermostat turns it off. Then a shorter boost around 5am. Ambient temperatures in Central Coast NSW drop to around 10 degrees overnight.
With no showers taken, but just household use (maybe 15 litres of actual water from the tank), it takes about 20 minutes to reheat. Washing machine is connected to cold only. With two longish showers (say 20+ minutes total and a decent water flow), it takes at least another hour. The early morning boost runs for 14-15 minutes.
So that means 35 minutes heating when no showers have been taken, to around 100+ minutes with those two showers. In Kwh that works out to 2.6 and 7.5 Kwh per day. At $0.159 per Kwh (Red Energy) that means about 80c for those two hot showers. Not much point checking power bills for average usage because I am frequently away, and more often in warmer periods.
Deme has not talked about usage. With a family, I could easily imagine 15-20 Kwh per day and more if the usage is not considered. If there are no leaks, then I would be watching how hot water is used more carefully. If you run out of hot water on occasions then I think that is your answer. But if it is Controlled Load 2, that also heats during the day, allowing more consumption without running out.
Do you use it for heating as well or just hot water usage?
Between 4 and 7kWh net usage per day, 210L heat pump HWS with 6.6kW solar. The solar generates about 15kWh per day in June (42kWh in summer) so with a battery it could theoretically be independent from the grid.
have a 300 litre hot water tank, electric, and on average the control load consumption is 40 kilowatt hours a day, which seems high?
Is that a heat pump system?
I did the math years ago for our peak electric 80L HWS - and calculated that my 15-minute shower used around 5kWh - milady's 8-minute shower might use say 2.5kWh
so if your 300L HWS is using 40kWh/day for my system that's like 8 people having a 15-minute shower per day - or 4 people having TWO 15-minute showers every day.
Check your usage - dishwasher & clothes washing machine (ours both use cold water only), any long runs uninsulated where hot water cools in the pipes ?
Yes and is it peak only, time of day, heat pump, or some other weird thing - and mostly - have you recently changed to a 'Smart' electricity meter - from what I've read, those babies can 'accidentally' charge you 10x as much as before - and when you try to argue with the company they ignore it or fob you off with 'computer must be right' - so grrr - sound like Avoid those if you don't already have them.
Lastly I got a tempering valve installed last time - HWS supply may be 60C to avoid legionnaires or some such bugs - but the tempering valve can be adjusted to mix cold water so you don't have piping hot water cooling in the long pipes, and you can just turn on hot tap mostly for showers so more efficient overall. Mine is set to deliver 45C at the laundry and kitchen spouts. Works for me. Also avoids scalding injuries for babies and old people.
Yeah nah that's cooked. I use 40kwhr in winter a day with an EV and exclusive air conditioner heating.
Electric heating is pretty uncommon around here but those with it that I know use about half the electricity I do
Where are you located? Hobart will differ from Darwin