Electricity heating conundrum!

[TheMitchells]

Having installed my elderly parents in a nearby bungalow, we are trying to sort out the heating systems and electricity costs.  It is a bit of a conundrum and maybe someone has an idea what could be causing the problem. 

The bungalow is heated by one night storage heater in the lounge and a rather large night storage system in a central cupboard, (left photo) through which air is blown when required into all the rooms, incudling the back of the lounge.  This is controled by a thermostat in the lounge.  The place also has a very large hot water tank in another cupboard which is also on the Economy 7 night time tarif. The econmy 7 stuff (tank and two NSH's) is on its own fused thing in the fuse box. 

 

 

Before buying the place, I asked about electricity bills and was informed that the average winter bills were about £90. Hhh. Dont think so!  We were taking reading of the electrcity over the course of the first couple of months as it got colder to make sure we had an idea of costs.  Here is the spreadsheet.

 

As you can see, the costs are far higher than expected.  and I havent the foggiest what happened on the21st and 22nd Nov!  Why did the night reading suddenly quadruple!  parents assure me that nothing changed from normal.  then we had two night really low! 

Our idea was to turn off each unit in turn to see how that effected the readings but 'something caused a major hiccup and they certainly cannot afford to have occasional costs of £12 anight. 

On Sunday (yesterday)after a few evenings of relative similar readings, we turned off the heater to the hot water tank.   And the evening costs did drop.  On feeling the tank this morning, the bottom third was cold, middle third warmish and the top hot.  So we are leaving it another night before turning it back on.  They dont use much water at all as they cannot get into the bath and apart from the washing machine occasionally, they use a sinkful per day washing dishes. 

The heating is set quite high as Dad feels the cold and the house is certainly warm when I go in but not excessively (usually around 21oC/70oF in the lounge).  They turn the thermostat up for about 10 mins in the morning then a bit more in the evening when the other nsh is probably not putting as much out.

 

Any ideas what could have caused the sudden increase the other evening?  Thats a lot of electricity to use.  And are we doing the right thing to try to calculate what each unit is costing to run?

 

I think we shall seriously be looking at replacing it all with a simple gas combi boiler in the summer.  There is gas in the street and we can see many similar bungalows are it connected.  And if we plan it with a future kitchen extension in mind, it will save us having to do it in a few years time. 

 

 

 

 

[DavidFrancis]

Why not turn off the hot water tank for an extended period to see what happens. I used to turn off my combi in the summer and used a kettle for washing up water. The washing machine can probably heat the water it needs. (Used to shower at the gym/swimming pool in case anyone is concerned!)

[TheMitchells]

yes, thats an option.  and I did think about getting them to the local sports centre for a shower there. 

 

[newhome]

Being on electric heating I have a similar spreadsheet and occasionally something strange happens that I try to make sense of. On the last 2 occasions when the daily tally has been higher than normal the following occured:

 

1. I set a new zone to heat that had been switched off before that. This always takes a bit of a hit until that zone is up to temperature 

2. boiler came on in the morning unexpectedly as I had managed to set one of the zones to need heat first thing in the morning when normally the boiler stays off. 

 

So both spikes were explainable.

 

My heating is a bit more predictable if the boiler comes on at the same times every day but there are occasional spikes as per the examples above. It's all about setting a system up in the optimum way for the occupants (this takes a bit of fiddling with to get it right), and then where there are spikes knowing what causes those spikes and adapting things as appropriate. That's my strategy so I would say you are on the right track here. Unfortunately whatever way you look at it electric is not a cheap way of heating a house. I also don't trust what people tell me so I would always ask for proof of bills during a house purchase. Water under the bridge now though. 

 

Not sure who your supplier is but my supplier's 10p rate (heating) has just been increased to 14p for 2019. Worth shopping about to switch suppliers if you can save money too. 

 

You say that the washing machine uses hot water? Is that the case? Most are cold fill only these day? Can it be set up to use the night rate too (and run at night clearly)? 

 

That looks to be quite a large tank for a (presumably) small house. I don't really know how economy 7 works but I thought that everything switched between night and daytime tariffs dependent on time of day? I think you need to work out how long the water needs to be heated to provide enough hot water for them to shower and set the heating to only heat to that level (via a timer?) at the time when it's most economical to do so. I presume it heats the top of the tank first for DHW? Mine does. When I want a shower in the summer I just stick the boiler on for 30 mins to heat enough water to shower. The bottom of the tank is still relatively cool after 30 mins but the hot water draws off the top and provides enough to shower. The water does cool down during the day but I don't use much hot water outside of showering other than for washing hands etc and there is just me here anyway. If I want a bath I need the boiler on for an hour rather than half an hour. Keeping my tank continually topped up and hot would not be economical at all. 

 

Not sure what caused your spikes but was there something odd like a power cut that may have caused it to go a bit haywire? 

 

If I had gas as an option here I would be switching to gas like a shot. A modern combi boiler should be much more economical and convenient for your parents. 

 

[ProDave]

That central blown air storage hater is an Electricair system. They were widely fitted in social housing near here in the past.  You can in fact still buy them and all the parts to maintain them, though they are mainly targeted at commercial heating now.

 

They are probably no better or worse than any other storage heater, except being blown they perhaps lose less heat when idle than an individual storage heater.

 

Let's face it here, this is probably an old leaky poorly insulated house so the consumption is to be expected. The only thing "wrong" was whoever quoted you a heating bill of £90, unless they meant £90 per month every month just for heating, then you may be somewhere close.

[newhome]

10 minutes ago, ProDave said:

Let's face it here, this is probably an old leaky poorly insulated house so the consumption is to be expected. The only thing "wrong" was whoever quoted you a heating bill of £90, unless they meant £90 per month every month just for heating, then you may be somewhere close.

 

Oh I had assumed that 'average winter bills' coming in at £90 were indeed per month. There is no chance of an electric system being run for much less than that IMO as compared to the unit price for gas electric is way more. 

[Temp]

Is there some sort of boost on the night storage heater or something else that might have been left on overnight? 116 units over say 12 hours is roughly 10 units an hour or 10kw. Not many things dissipate that much. Don't think an oven would do it.

 

 

Edited December 3, 2018 by Temp

[ProDave]

This is the modern version of the Electricair https://www.dimplex.co.uk/product/electricaire-r1073

 

It has a 10KW element and can store 73KWh, so even if it's thermostat was stuck on, it could not consume more than 73KWh in one night.

 

You mention another storage heater and there is the hot water tank, each of these will have a 3KW heater so can consume a maximum of 21Kwh each, so that will give you a grand total of 115KWh.  So for some reason that night, everything was running flat out. What you might expect the first night it was turned on from cold?

 

The thermostat in the living room, usually in conjunction with a programmer, controls the fan to blow heat out of the heater to the rooms, that is independant of the themostat on the unit itself that sets the storage core temperature during the overnight charge.

[Ed Davies]

3 kW into the hot water tank, 3 kW into the small NSH, 4 kW into the big one would be 10 kW.

[Ed Davies]

For the 12 days from 2018-11-21 to 2018-12-03 the night usage was 417 units (82459 - 81988). That's equivalent to a steady 1.45 kW. That actually seems quite low to me.

[TheMitchells]

33 minutes ago, ProDave said:

This is the modern version of the Electricair https://www.dimplex.co.uk/product/electricaire-r1073

 

It has a 10KW element and can store 73KWh, so even if it's thermostat was stuck on, it could not consume more than 73KWh in one night.

 

You mention another storage heater and there is the hot water tank, each of these will have a 3KW heater so can consume a maximum of 21Kwh each, so that will give you a grand total of 115KWh.  So for some reason that night, everything was running flat out. What you might expect the first night it was turned on from cold?

 

Yes, that would have explained it but it wasnt - they were all up to temperature and it wasnt even the night it turned really cold. 

 

45 minutes ago, Temp said:

Is there some sort of boost on the night storage heater or something else that might have been left on overnight? 116 units over say 12 hours is roughly 10 units an hour or 10kw. Not many things dissipate that much. Don't think an oven would do it.

 

Possibly - there is a boost for evenings when you can open a flap and it lets the heat out of the core.  But it should not have been open - although Dad may have accidently changed it.  Its about the only thing that could do it. But still seems a lot of power.  I just hope it doesnt happen again.  We are doing readings every day now. 

 

Unfortunatly the washing machine cannot be used at night - the economy 7 comes on at 12.30 and goes off around 7am.  And for some reason, it cannot be turned on with a timer. it has to be pressed to set it off.  And its on the 'socket' ring at the consumer unit.  the economy 7 stuff has their own consumer unit.

[newhome]

6 minutes ago, TheMitchells said:

Unfortunatly the washing machine cannot be used at night

 

If mine is anything to go by a washing machine doesn't amount to much anyway at 40 degrees, say 50p a wash, and I don't suppose your parents have it on all the time. I use mine for 2 or 3 washes a week. You could encourage them to only use it when there is a full load but maybe they do that anyway. I have fiddled around with bits and bobs here but by far the biggest whack is the heating. My boiler eats 24kw every hour when it's running full speed. I generally get away with it using about 36kw per day for heating and hot water by timing things carefully, and that is with only me here and only heating some of the rooms. I dread to think how much it would cost a family of 4. Possibly half as much again. 

[TheMitchells]

On 03/12/2018 at 20:41, newhome said:

 

If mine is anything to go by a washing machine doesn't amount to much anyway at 40 degrees, say 50p a wash, and I don't suppose your parents have it on all the time. I use mine for 2 or 3 washes a week. You could encourage them to only use it when there is a full load but maybe they do that anyway. I have fiddled around with bits and bobs here but by far the biggest whack is the heating. My boiler eats 24kw every hour when it's running full speed. I generally get away with it using about 36kw per day for heating and hot water by timing things carefully, and that is with only me here and only heating some of the rooms. I dread to think how much it would cost a family of 4. Possibly half as much again. 

No they dont use it very often, about 2-3 times a week.  It is scary how much we all use for heating our homes.  and we dont think the bungalow is very leaky.  It has had cavity insulation added and there is plenty insulatio in the attic.  But they do like it warm.  They have even put in an order for a new electric fire so when they just want a little extra!  But when they get the their age, I guess if they want it hot, why shouldnt they have it hot.  ?

[ProDave]

11 minutes ago, TheMitchells said:

It is scary how much we all use for heating our homes.

So far this winter I am averaging less than £1 per day for space heating.  I am not losing sleep at how I will pay the bill.

 

If we were serious about climate change and reducing fuel use, a house like ours would be normal, not just something a few of us strive to build.

 

And this is the Highlands, -9 last night, daytime high today -6, but you would not know it unless you step outside (I guess the frost on the outside of the windows might give a hint)