Power Consumption Advice

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Shapenz

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Topic # 105877 12-Jul-2012 19:48

Hi there,

I'm hoping someone might be able to give me some advice on the power consumption in our house.

In March this year we moved houses and noticed an instant increase in our power bills. It wasn't 'so' bad up until now but this latest one has just been huge.

I have thought about what has changed since last year and outside of us moving properties these are the things that altered our energy.

There were four of us living in the old house. Now, there are 3 and I typically shower at the gym in the morning so that should save power.

We used to have a oil fin heater but that broke so we replaced it with a small 1200W fan heater from the warehouse. It is just for the bedroom so while it doesn't put out much heat it is enough.

I bought my wife a electric blanket for this house as it is chilly. It's not the type that goes under your sheets but more like a throw : It's actually the Sunbeam heated throw from Noel Leemings.

Apart from that our appliances are all the same. I checked the how water cylinder and made sure it was turned down to 55. If anything there seems to be a shortage of hot water here rather than too much.

Last year July Reading (Actual) 555kWh $178
This year July Reading (Actual) 1311kWh $382.46

I'm sure from those number you can see my alarm. When we moved in here our bill jumped from $180 to $220, then next month was $250, then the previous one was $280 - but this latest jump is huge and more than double our bill from last year!

Any advice? I tried to get one of those Belkin power meters tonight but Noels, DSE and JB Hifi all told me they didn't sell them :(

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Reply # 654781 12-Jul-2012 19:57

What type of house are you in now compared to before?

You need to get your hot water above 60 degrees for at least an hour a day to prevent legionnaires disease. See here

Basically heaters run until the room is up to temperature and then switch off. If the house is well insulated, doesn't have too many big draughts etc then it will retain the heat. The heater could spend a lot of time off.

If the house isn't like the above the heater will be running a lot more to replace the heat being lost outside.

So, the same heater can use more or less power depending on the environment it's running in.

Shapenz

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Reply # 654783 12-Jul-2012 20:00

HI Jaxson, opps I will have to adjust that back up.

Our heater only runs for a few hours in the evening when we are home - usually from 8-10. It doesn't seem to have a thermostat as suck and we just run it on full power for that time. It's a very small heater so only really puts out decent heat at it's max.

gzt

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Reply # 654902 13-Jul-2012 09:34

The Belkin device measures only one appliance at a time. That will not be much help. Btw, there may be one on TradeMe at the moment.

Harvey Norman still list them online:

http://www.harveynorman.co.nz/belkin-conserve-insight.html

Better than that - a wireless household power meter will be more use to you. Many provide the ability to import data into a PC and see graphed usage over time. The Current Cost meter is the most popular on Geekzone. There are many others available - click the link below for a list available in NZ.

You can make good progress just looking at your outdoor meter manually as well.

IME the biggest single cause of runaway power cost in winter is badly insulated or less than ideally installed hot water cylinders, but particularly older ones installed in roof spaces. In extreme cases in really cold weather they cool faster than the element can heat them and will remain on for ages. Also remember as the temperature of the input water drops in winter it requires more energy to heat it up. In the extreme cases the payback on an insulation wrap and a couple of meters of output insulation is rapid indeed.

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sleemanj

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Reply # 655004 13-Jul-2012 12:52

Assuming you are renting here, are there any sub-dwellings, sheds, garage etc which you don't use but are on the property. It wouldn't be the first time "mysterious increased power usage" is because you were paying for a dodgy landlord's power usage.

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Jaxson

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Reply # 655014 13-Jul-2012 12:58

Yeah I was going to suggest leaking hot water pipes etc, as this can bleed away energy.

As before though, please describe your house/s. No one can really comment unless you provide a bit more info.

As above also, if you're in a shared complex are you sure the are separate meters and you're not paying form someone elses power? How do you heat the lounge common areas? Are you saying your entire house has only one small fan heater in a bedroom, running for only a few hours a night?

Are you living with the same 3 people? And are they using the same amount of power as before also?

gzt

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Reply # 655025 13-Jul-2012 13:11

Shapenz: We used to have a oil fin heater but that broke so we replaced it with a small 1200W fan heater from the warehouse. It is just for the bedroom so while it doesn't put out much heat it is enough.

Oil heaters have a thermostat regulator and continue to radiate that stored heat even when the thermostat has turned off the heating element. Fan heaters have a thermostat regulator but when the thermostat has turned off the heating element there is no stored heat at all. In practice this usually means fan heaters are 'on' far longer than an equivalent oil heater.

How many hours a day?

stevenz

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Reply # 655039 13-Jul-2012 13:33

You need to get your hot water above 60 degrees for at least an hour a day to prevent legionnaires disease. See here

Now that's a new one on me, I've always turned the temp down to about 55 degrees to stop poor cylinders from wasting too much power.

Our power bill goes up & down as much as 30-40% for no obvious reason from month to month, and we never get estimates, always actual reads.

Anything that acts as a heater, electric blanket or otherwise, will use huge amounts of power so I'd always be tempted to point-finger at that.

Probably the most obvious culprit I've found is clothes dryers. If people get lazy and put clothes in them instead of on the line (which we have to do lately as Welly is too damp for anything to dry at the moment), then they chew a lot of juice.

@KnightNZ

timmmay

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Reply # 655057 13-Jul-2012 13:49

The heater will be costing about 55c/day if it's run for two hours, so $15/month.

Hot water uses around 1/3 of most peoples power, heating 1/3, and the rest appliances. It's not heating, so I have to guess hot water. Is there a leak? Check the roof to see if it's overflowing out the top. How long do people shower for each day?

My last power bill was $300 or so, actual read. My house is old but well insulated, and we have a huge but efficient heat pump on 21 degrees from 5pm until 10pm, then on 17 degrees from 10pm until 7am. Weekends we don't turn it off. We also run another heat pump for a short time each day, a fan heater in my office, and an oil heater on low in the bedroom. We have computers on, a big TV and AV system. There's two people living in the house, and we have two showers a day each. So your $350 for three people and no heating sounds way too high.

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zhuyan

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Reply # 655206 13-Jul-2012 18:24

timmmay: The heater will be costing about 55c/day if it's run for two hours, so $15/month.

Hot water uses around 1/3 of most peoples power, heating 1/3, and the rest appliances. It's not heating, so I have to guess hot water. Is there a leak? Check the roof to see if it's overflowing out the top. How long do people shower for each day?

My last power bill was $300 or so, actual read. My house is old but well insulated, and we have a huge but efficient heat pump on 21 degrees from 5pm until 10pm, then on 17 degrees from 10pm until 7am. Weekends we don't turn it off. We also run another heat pump for a short time each day, a fan heater in my office, and an oil heater on low in the bedroom. We have computers on, a big TV and AV system. There's two people living in the house, and we have two showers a day each. So your $350 for three people and no heating sounds way too high.

$300 for all that is not bad at all and is actually quite impressive? Which power company are you with and what plan?

I'm with Empower and am on a Day/Night Low User Plan, which means my hot water cylinder is not hooked up with power between 7am and 9pm every day. There are two people living in the house so you see having two showers a day each (4 showers) would be mission impossible for us as the hot water simply runs out.

We have only one standard size heat pump in the lounge and we have it on like 25 degrees between 6-11pm and then turn it off. On weekends, we have it on from 11am until 11pm. In the bedroom we have one electric heater which we turn on for about 1 hour before sleep. Apart from that, just usual whiteware, 40" TV plus ps3.

The latest bill just arrived today and it showed $316.

I probably need to switch power company shortly.

hashbrown

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Reply # 655208 13-Jul-2012 18:29

To the OP

If you haven't already, locate your meter and confirm the numbers match up with what's on your bill. Next, start taking your own readings of what you are using on a daily basis. Checking what you use between going to bed and when you get up would be interesting.

shrub

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Reply # 655219 13-Jul-2012 19:07

Are you in a block of flats by chance? When there is multiple meters involved you could be paying for your neighbors.

Shapenz

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Reply # 655304 14-Jul-2012 00:17

Jaxson: Yeah I was going to suggest leaking hot water pipes etc, as this can bleed away energy.

As before though, please describe your house/s. No one can really comment unless you provide a bit more info.

As above also, if you're in a shared complex are you sure the are separate meters and you're not paying form someone elses power? How do you heat the lounge common areas? Are you saying your entire house has only one small fan heater in a bedroom, running for only a few hours a night?

Are you living with the same 3 people? And are they using the same amount of power as before also?

Hi Jaxson, yes it the same 3 people (we are a family) with the same appliances. We only really heat the bedroom because that is the only time we are actually home. So, there is no point us heating the common area's when we aren't actually here.

In our previous house we had an extra as my father in law was living with us but is now in hospital.

Previously we were in a block of flats that was joined to another block of flats. Now we are in a stand alone house which is much older -but not as old as the weatherboard bungalow type oh house.

The thought of the hot water has crossed my mind as we seem to be short of hot water. So for instance, if you do a load a washing (5.5kg machine) on warm there is only enough water for a quick shower.

Is this likely to be a leak or more likely bad insulation on the cylinder itself?

Probably also worth mentioning is it is a rental so I won't be doing anything major to the house. Don't have a dryer

We have a digital meter outside the house which tells me our current load is about 2700kW. Does that seem about right? - A quick google didn't seem to find me a result.

ubergeeknz

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Reply # 655343 14-Jul-2012 06:14

I'd say your hot water is overflowing. if you cannot see the overflow, turn off all hot taps and put your ear to it, that'll tell you (bet you hear water flowing) if so you will need a plumber, either your nefa or overflow valve will be stuffed.

gzt

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Reply # 655354 14-Jul-2012 09:35

Shapenz: We have a digital meter outside the house which tells me our current load is about 2700kW. Does that seem about right? - A quick google didn't seem to find me a result.

It depends what is turned on at that time. Medium size hot water cylinder elements are usually about 2700W.

Regarding your question about hot water availability after running the washing machine - what is the capacity of your hot water cylinder?

Assuming your capacity is good, a failing thermostat can cause less hot water to be present. A failing element can have a similar effect as well.

Some time ago I dealt with a cylinder with a failing heating element. It was putting out much less wattage than required and therefore was on most of the time but completely ineffective. Even with the reduced wattage, the power bill was actually higher than normal due to the cumulative on time. The failure occurred in winter and the cylinder was inadequately insulated for the position so the heat loss was on the high side as well contributing to the effect. After the failure the electrician called to replace the element replaced the thermostat at the same time to be on the safe side due to the age of the installation.

Anyway, we've all been harping on about your hot water a bit so you have a lot of ideas to follow up and confirm or rule out there.

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hashbrown

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Reply # 655371 14-Jul-2012 10:08

gzt:
Shapenz: We have a digital meter outside the house which tells me our current load is about 2700kW. Does that seem about right? - A quick google didn't seem to find me a result.

It depends what is turned on at that time. Medium size hot water cylinder elements are usually about 2700W.

So turn off your hot water cylinder and see what it drops to. Assuming it's during the day (no heating, no lighting, no cooking) it should drop to a few hundred watts.

Did you check that the meter number matched the one on the bill and the total kWh was in the same ballpark as the readings on your bill?

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