Power Consumption Advice

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timmmay

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#655440 14-Jul-2012 11:49

zhuyan:
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.

Meridian I think, standard plan. My hot water's allowed to heat any time. I've done a lot of work on efficiency, lots of insulation top bottom and sides, retrofit double glazing.

25 degrees is pretty warm, the higher you go the higher the heat loss. I prefer to wear two layers and keep it at 20-22 and save the money.

timmmay

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#655441 14-Jul-2012 11:51

Shapenz: 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.

A hot wash would take a large portion of a standard cylinder. I only ever do lukewarm washes unless something's insanely dirty.

I really think hot water is the only place you could be spending that money, and overflowing or leaks is the most likely way.

Shapenz

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#655712 14-Jul-2012 20:59

Okay so turned the water off and with energy saving bulbs in on in three rooms, TIVO on, TV in standby and fridge/freezer on the load was 700. Turn the hot water on and this jumps to 2700. Which would make sense with the hot water cylinder being a 2000kw.

My questions is though - should the cylinder be drawing that constantly - or only when I'm running hot water?

timmmay

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#655718 14-Jul-2012 21:31

The cylinder should draw that to heat water, which should be after you've used hot water, and occasionally to top it off. If it's drawing it all the time, or even most of the time, it means you have a hot water leak.

Jaxson

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#655721 14-Jul-2012 21:46

timmmay: The cylinder should draw that to heat water, which should be after you've used hot water, and occasionally to top it off. If it's drawing it all the time, or even most of the time, it means you have a hot water leak.

Or it can mean your tank thermostat is faulty and it's heating all the time, usually boiling out the overflow pipe on the roof....

timmmay

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#655722 14-Jul-2012 21:47

Yep that too, I forgot that, said it earlier.

gzt

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#655740 14-Jul-2012 22:50

Jaxson:
timmmay: The cylinder should draw that to heat water, which should be after you've used hot water, and occasionally to top it off. If it's drawing it all the time, or even most of the time, it means you have a hot water leak.

Or it can mean your tank thermostat is faulty and it's heating all the time, usually boiling out the overflow pipe on the roof....

The most common condition causing water to flow out the header is a failing pressure regulator on the input side.

Btw - there are a fair number of installations where a pressure relief valve system is used instead. These vent to an outside wall or into some other drain (even randomly under the house). It can save a lot of space and pipe routing but more parts require more maintenance than a simple header pipe.

According to this - http://www.mrplumber.co.nz/wawcs0131903/idDetails=164 normal thermal expansion would see you lose up to 3% through a relief valve (usually on the cold side).

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gzt

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#655741 14-Jul-2012 22:56

Shapenz: Okay so turned the water off and with energy saving bulbs in on in three rooms, TIVO on, TV in standby and fridge/freezer on the load was 700. Turn the hot water on and this jumps to 2700. Which would make sense with the hot water cylinder being a 2000kw.

It is also worth turning absolutely everything off completely to find out if you have some mystery load remaining that you don't know about.

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#655822 15-Jul-2012 09:05

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

Are you sure June 2011 wasn't a high estimated reading (making July 2011 a low actual reading) and June 2012 a low estimate (making current month a high actual)?

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#657525 18-Jul-2012 11:28

Moved to correct forum.

Niel

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#657720 18-Jul-2012 15:37

A pressure relief valve can also periodically get dirt/grit in it preventing it from closing. You will hear the faint stream of water from it. Briefly operating the manual override will clear it.

Our relief valve overflows into ~20mm PVC pipe that runs through the rib raft concrete foundation to a gully trap.

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