Electricity questions (longish)

[ARW]

One of my friends has just gone to an archive group annual meeting - she says that there two women that talk enough hot air to keep everyone warm and they should put their efforts into archiving:-)

See my other post - but if you ever get in there again at a weekend or evening and want to WhatsApp me a video I'll try to talk you through more of what I can see. But take some snips to remove some of the plastic cable ties so you can easily trace the meter tails that are cable tied up together and a couple of cable ties to put them back together..

[Chris Hogg]

I'm thinking that the chapel get billed by SSE for what's on the WPD meter, and we pay the chapel for what's on the secondary meter at the rate quoted by SSE on the bill. The numbers they give us on the bill generally tally with those on the secondary meter. But what goes through secondary meter, I don't know. I guess it's all the juice going to DB2 (red) and some of what goes to DB4 (yellow & some blue), and the remainder of the blue phase goes through DB3. This means that the blue phase must divide somewhere before the secondary meter. I know nothing about DB1.

[Chris Hogg]

Yes, I know that if you don't take full advantage of E7, it can actually work out more expensive due to the higher standard rate that you pay.

And it would require some engineering around the outside to install it all. Even if we/they could afford it (which we can't) I doubt that they'd let us do it.

[Chris Hogg]

No chance! We are continuously on the look-out for suitable and preferably permanent premises, but this is a holiday area, anything suitable is soon snapped up by developers for conversion into holiday accommodation, prices are astronomical, and grants that we might get come nowhere near the asking prices. We're talking figures well in excess of £500,000 here.

[Andy Burns]

Only you know which of the names on the MCBs (class-room, staff-room etc) correspond to areas which are theirs vs yours ... then you have to trust they're labelled accurately.

[Mike Humphrey]

There's two ways of doing E7. One is that the meter has a switched output, which feeds the off-peak loads. The other is that the meter has only a single (unswitched) output, and the off peak loads are switched by a separate timer. In this case it's up to the owner to make sure that the timer switching the load is set to the correct time to take advantage of the cheap rates.

Mike

[Chris Hogg]

Ours may be like that. There is a separate timer that seems to control a high-current switch, but what it's actually switching, I'm not sure. In that set-up, how would the supplier know that you've got the timer correctly set, to say midnight to 7AM, and not just any old time period perhaps even longer that 7 hours, and how would the supplier know what power you were using between midnight and 7AM anyway to be able to charge you at the lower rate?

I've just been shown the most recent invoice to the chapel from SSE. It shows that the chapel is on 'Variable Business Rate Off Peak', but there is only one line of energy recorded, so it doesn't seem to switch at any time and all the electricity used is at the one rate, which presently is 43.23p/kWh, with a standing charge of 101.46p/hour (ouch!). Back in January the figures were 22.199 and 65.46 respectively. Looking at the long list of business rates on offer from SSE, it is one of the cheapest singe-rates they offer.

If we're only on a single rate regardless of time-of-day, the timer and associated switch would seem redundant.

[Andy Burns]

They wouldn't know, just that if your clock was wrong you'd be overpaying for the heating load.

an E7 meter has multiple registers, ISTR the WPD meter did have a button to display them one by one, just having an E7 meter doesn't guarantee being on an E7 tariff.

[Jack Harry Teesdale]

From this latest information, I would conclude that the 'Off Peak' name is a red herring and the NSH's are not being charged on an E7 rate and that you are on SSE's best available rate irrespective. The other tariffs with 'Night Rate' are more expensive!

Therefore, to save money you need to reduce consumption for your Archive unit and be sure that what is going through your meter is actually being used solely by your Archive.

Either way with unit prices at those levels and a standing charge of £1+ per day it won't be easy to make significant savings.

[Theo]

I can think of two scenarios. Either it's a mistake, and the 'off peak' rate is in addition to a more expensive rate that should be under a different tariff but isn't. Or it might have been a legacy tariff which has been incorporated into a cheap-ish replacement (about 15 years ago SSE had some funky tariffs that were cheap except for a varying 3 hours a day and such, which have all been retired).

Since the private meter for the Archive is not a dual rate meter, there's no way you could be billed on an E7 tariff anyway - it doesn't log how many units are used for day or night.

The timeswitch is still relevant though: it's how the heaters are set to go on and off. There isn't an E7 saving (at the moment, although tariffs may change) but you still don't want them running 24/7.

I think the key point here is there's no advantage to storage heaters, so don't use them as storage heaters.

Being an archive is problematic, because you need a certain level of temperature and humidity control. However aside from that I'd look into smarter controls on the heaters. For example, decide what low temperature is safe for the document storage, maybe fit dehumidifiers on a humidistat to kick in if it gets damp. And then just use fan or radiant heaters to warm the place up when people are in it.

It could be worth looking at air2air heatpump air conditioning units which would offer both more efficient heating and also a dehumidifier function. Starting price roughly £1K, which might not be so unaffordable given the potential upcoming bills.

Also, look at insulation if that's at all possible, and jump on anything that might introduce damp (dodgy guttering etc).

Maybe look into grants from the council etc?

Theo

[Mike Humphrey]

In that scenario, there are two timers. One is built in to the meter (older meters have an external one, but modern ones have it built in). This controls whether the meter records "peak" or "off-peak" use. Actually it usually controls if it records "rate 1" or "rate 2" - it's the supplier that knows what rates they correspond to. This doesn't control the load at all. The other switches the heaters on and off, and the supplier neither knows nor cares what this one does. If set correctly, it switches them on just after off-peak starts, and off just before it ends. If set incorrectly, it switches the heaters on during peak rate and you get charged a fortune.

Yes, and storage heaters are probably not an appropriate heating solution in that case. On a single-rate tariff, simple electric heaters such as convectors or oil-filled radiators will probably be cheaper, as they're not heating the building at night when there's no-one there, and are more controllable when you are there. A heat pump would be cheaper to run, though at a huge capital cost. Or gas, LPG or oil heating.

If the storage heaters are staying, it would be worth investigating what split rate tariffs are available. They may or may not be cheaper, as the day rate is usually higher than the single rate.

Mike

[Chris Hogg]

Many thanks to all who've contributed to this thread. I certainly have a better understanding of the set-up now, and in particular that there's no E7 or it's 3-phase equivalent in place.

I have yet to discover the purpose of the timer and associated switch, and what it actually switches. It may well be a legacy from when there was something like an E7 supply. Alternatively it may just be a precaution against leaving the NS heaters running 24/7. Without poking about and following the cables carefully (which is probably the job of a qualified electrician, which I am not), I may never know.

As for cheaper forms of heating and insulation, I have already had all the windows covered in bubble wrap, by way of poor man's double glazing. The are quite a few windows, single pane, quite high up, there is no view to miss, and they probably date from when the school-room was built (~1930). Winter will tell whether it actually makes any difference.

The two doors are in the process of being draught-proofed. Because they are old and warped, I've had to resort to 'Atomic Strip'

I've had some in my bits-box for a long time (>25 yrs?), and quite glad to have eventually found a use for it. My parents house used it circa 1950 so it's been around for many decades.

We have considered dehumidifiers. They weren't going to be cheap to run at the best of times, but the recent price rises virtually rule out anything that uses other than the minimum amount of electricity. Anything like an air-sourced heat-pump is in the realms of fantasy, I'm afraid, even assuming the chapel would allow it to be fitted.

Thanks again to everyone.

[Chris Hogg]

My previous property was on E7, and there was a mechanical time-clock. The arrangement was very much like this

clock set the meter to record at the cheap rate or daytime rate. and the totals were displayed on separate dials. When on cheap rate, the whole house, ring mains, lights, the lot, were on the cheap rate, not just NS heaters (but they were on their own circuit and did get automatically switched off during the day). It didn't change, winter to summer, i.e, it didn't account for BST. If you had a dishwasher or washing machine that was on a time clock, you had to leave the settings on the clock alone and not be fooled into changing them.

[Andy Burns]

Nope, never heard of, or seen it in use.

[Andy Burns]

I was going to ask HFM? But it seems you mean /day not /hour

[Chris Hogg]

Oops! yes, per day! It's actually not quite that bad, because the chapel splits that cost equally between us, so it actually costs the Archive only 50.73 p/day. Still a lot for a small charity that relies entirely on donations, especially as money everywhere is tight these days.

[Theo]

Understood. I think an archive with no form of temperature or humidity control is on borrowed time, but there you are.

One thing you might do is see if you can borrow or hire a thermal camera. Often there are community groups like 'Transition ...' or councils who lend them out, or the usual hire places have them. If used on a cold (or hot) day you can see where the heat is most escaping. Then you can target those spots that make the biggest difference.

(a basic one that plugs into a smartphone is about £200 to buy)

Theo

[George Miles]

Infrared heat gun pings a dot and tells the temperature where it hits, about £15 from ebay. very useful

[Andrew]

But only if you point it at the correct type of surface. Ideally, matt grey, like the colour of a Kodak Grey Card and not a white shiny surface. The latter seems to confuse my somewhat elderly laser thermometer.

[alan_m]

Plus the area being measured is a lot larger than the laser spot. For instance pointing at it from 2m away the area being measured will be

25cm diameter. It is unlikely to detect to detect "cracks" in isulation etc.