High Power Bills

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whitecd

40 posts

Geek

#151514 27-Aug-2014 22:07

So we shifted to Invercargill from Christchurch (another discussion) and moved into a rented new 3 bd house with heat pump and double glazing on a back section. Our power bill's are much the same as they were when we lived in Chch $180-$200 (similar sized house).

Heat pump is on 18 degrees only at night, and the last 5 months since we have lived here the temperature has been warmer than CHCH.

The difference is that in our new house we have Gas Hot water and cooking. Correct me if I'm wrong but I would have thought that these two were the big power consumers in any house. Unit and Daily charges are much the same however we are still consistently paying around $200 for power and I can't work out why...

Any ideas would be appreciated...

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#1116888 27-Aug-2014 22:24

are you getting read bills or estimates?

Damager

2125 posts

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#1116889 27-Aug-2014 22:29

Got a smart meter? Most retailers with smart meters mean you can check your daily and hourly usage, and the physical meter will show a load reading. I'm thinking a heat pump on for 8 ish hours a night so around maybe 2 units an hour, 16 units a day, 480 units a month (30 days). Say 25 cents/kWh + GST = $138.00 inc GST. Of course thats 8 hours a day for 30 days but helps give an indication .

I'm not sure if the temperature setting affects the output ?

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mattwnz

20111 posts

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#1116907 27-Aug-2014 22:36

Is that 18 degrees all night when you are also in bed? That sounds warm when you are in bed.

chevrolux

4962 posts

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#1116908 27-Aug-2014 22:38

The line charge for gas easily gets rid any savings you may make.

itxtme

2102 posts

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#1116911 27-Aug-2014 23:09

I didnt think they had mains gas in the south island?

Damager

2125 posts

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#1116912 27-Aug-2014 23:12

itxtme: I didnt think they had mains gas in the south island?

They don't. LPG?

whitecd

40 posts

Geek

#1116913 27-Aug-2014 23:14

l43a2: are you getting read bills or estimates?

I am doing readings and we average 26 units per day, In Christchurch we had the same heating habits, left heat pump on at night @ 18degrees (young child in the house) and we averaged around 16 units. Both heat pumps are 6kw and energy star rated. I am sure this is a large portion of the cost, the issue is that the other half - two thirds of the bill at least $100 are for lighting (all LED's), fridge, electronics (laptop, tv [never used] etc). Seems very high

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Damager

2125 posts

Uber Geek

#1116916 27-Aug-2014 23:22

whitecd:
l43a2: are you getting read bills or estimates?

I am doing readings and we average 26 units per day, In Christchurch we had the same heating habits, left heat pump on at night @ 18degrees (young child in the house) and we averaged around 16 units. Both heat pumps are 6kw and energy star rated. I am sure this is a large portion of the cost, the issue is that the other half - two thirds of the bill at least $100 are for lighting (all LED's), fridge, electronics (laptop, tv [never used] etc). Seems very high

Have you got a smart meter that has a load reading? If so, check the load with everything on and then start turning appliances off one by one and see what drops show on the load. You can't really compare usage across different houses unless everything is exactly the same.

whitecd

40 posts

Geek

#1116920 27-Aug-2014 23:34

Damager:
whitecd:
l43a2: are you getting read bills or estimates?

I am doing readings and we average 26 units per day, In Christchurch we had the same heating habits, left heat pump on at night @ 18degrees (young child in the house) and we averaged around 16 units. Both heat pumps are 6kw and energy star rated. I am sure this is a large portion of the cost, the issue is that the other half - two thirds of the bill at least $100 are for lighting (all LED's), fridge, electronics (laptop, tv [never used] etc). Seems very high

Have you got a smart meter that has a load reading? If so, check the load with everything on and then start turning appliances off one by one and see what drops show on the load. You can't really compare usage across different houses unless everything is exactly the same.

No just a normal meter, this would make the task difficult. The issue is the stuff I had in this house is exactly the stuff I had in the last. With our change to gas costs should have dropped significantly. Do the gas to hot water boxes (excuse by ignorance) use any power to function?

charsleysa

597 posts

Ultimate Geek

#1116921 27-Aug-2014 23:41

Just another thing to add, if you have a smart meter and mostly use the heatpumps overnight then consider switching to day/night rates.

Day/night rates basically are two rates, one for day and one for night, compared to the standard anytime rate.

Day/night rates are usually 2c more during the day and 10c less during the night.

If you use lots of electricity at night then day/night rates can save you a lot of money.

Regards
Stefan Andres Charsley

garbonzai

315 posts

Ultimate Geek

#1116924 28-Aug-2014 00:30

Do you have your heat pump set to "heat" and not "auto", very inefficient with set to auto as they reverse there cycle constantly which uses max power to alternate between heating and cooling to maintain the set temperature, on heat it just reduces or increases power or 'ticks' over to maintain set temp. What temperature do you have set during the day? Gas water uses power for its igniter, which uses next to nothing, lighting if energy efficient bulbs/led won't use much, neither will your electronic gizmos, unless you have a large Plasma Tv.

So the 2 main culprits are hot water (but your on gas) and heating (1 x heat pump), can you log into your power companies account and check power usage by per-half hour, that will tell you what time of the day it's being used the most.

Sugest turn heat pump down to 16 (heat only) for night or off and use timer to come on half an hour before you get up, also does the place have good heavy drapes/curtains to keep cold from windows away.

Anyway, past my bed time, good luck

Aredwood

3885 posts

Uber Geek

#1116940 28-Aug-2014 01:44

I am having the same issue but in Auckland. Bills are around $150 month in Summer and around $250 month in Winter. Cooking is gas (both stovetop and oven) Heating is by my homemade oil boiler which also heats hot water in winter. Solar panels for hot water in Summer. Lighting is mixture of LED and fluro tubes. As part of my investigations I connected a (non smart) but digital electricity meter is series with the power company billing meter. Both recorded the same usage. Have got it measuring power to just the boiler system (uses power for pumps and a fan) Usage is about $100 per month. So this means Im using $150 per month on just lights, other electric motors, and electronic devices. Have already checked the fridges - used only 3 to 5 units per day (combined usage). Boiler is inline with what I was expecting. Next thing to check is the house water pump.

But my theory is that the electricity meters are over reading power that is drawn by electronic power supplies. (any device that has a power supply stage the rectifies the incoming mains then feeds in into a filter capacitor.) This would include all the computers, LED lighting, and various other electronic devices in the house. In other words billing me based on the KVA used by my house instead of the KW.

I have been doing some testing with the check meter. By connecting a light dimmer and some halogen lights to it. At some light dimmer settings the meter doesn't register any current flow even though the lights are still dimly glowing. Need to do some more testing including connecting my oscilloscope to the light dimmer output to confirm what conditions cause the meter to not read power used. My theory being that the smart meters are taking a current measurement at the peak of the AC waveform, Another measurement at the zero crossing point of the waveform (to measure reactive current) and a voltage measurement. This would mean they will correctly measure resistive loads, inductive loads (both lagging and leading) but not pulsed loads from electronic power supplies. As they are not taking current readings at other parts of the waveform. The meter will think that the load from a power supply is actually just a large resistive load. So it will over bill.

kiwirock

685 posts

Ultimate Geek

#1116953 28-Aug-2014 05:32

Welcome to the cold south.

My heating bill is around $230, for electric night only hot water and 3kW scope fan heater on thermostat 15 hours a day with the room around 18-20 no double glazing and open plan living/kitchen.

If you're on LPG it shouldn't be that high.

Are you running a water bed or tropical fish tanks or something bizzare like that?

You need to break down your bill. It could be line charges you're paying the most for. I only pay around $13 a month line charges on a low user power account with a higher unit rate. Normal account is about $56 a month before units added at a slightly lower rate.

To test your meter, get a 2KW fan heater, switch everything else off in the house, and run it on 2KW. After 30 minutes the main/24 hour power meter should have moved half a unit or the 1/10 unit should have moved 5.

Heatpumps don't perform so well down here. Depending on the brand the defrost a lot. You HAVE to have an inverter type to be comfortable down here.

If you have a Toshiba or Daikin inverter, make sure the fan is set to auto. Having it on high on some models forces the inverter system to crank right up to max capcity when it doesn't need too.

There's a possibility also that your heatpump is failing. You may have a bad reversing valve on an older unit like 6+ year old Fujitsu's. This would be sucking up the power on any heat setting. The nylon valve wears out and the units get stuck in a half heat/cool mode and recycle refridgerant in the outdoor unit instead of pump it all through the indoor unit.

It could also be an electronic controlled expansion valve or low on gas etc... I've seen Mitsi's needing regassed a lot down here. My preference is Toshiba Inverter, they built the first, made the newer efficnet gas, and you can ramp the inverter down to only about 300-500 Watts by manually dropping the fan speed over night.

Do you have more than 1 meter still? Getting charged line charges for both? Or worse 3 if you have an old night-store meter etc...?

bfginger

1255 posts

Uber Geek

#1116957 28-Aug-2014 06:06

What model heat pump do you have? It may not be as efficient as the old house's.

Goosey

2795 posts

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Subscriber

#1116972 28-Aug-2014 07:16

As with the other reccomendations, check the heat pump type and condition and Id also check your HWC thermostat is set to a reasonable range and check that it's not 'overboiling'. Might also pay to check what your fridge and freezer are doing. Clunky old beer fridges tend to suck the juice.

How big is this house compared to your previous house?

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