Economy 7

[mrcharly-YHT]

MsC has moved into a flat that has electric cooker and all water heating + central heating is electric.

There is an 'economy 7' meter. At least I think it is one, there is a high and a low figure on the meter.

Never having lived with one of these, I'm pretty ignorant. Had a read of the uswitch page and it sounds like unwise use could result in huge bills.

Anyone have any advice?

[trekker12]

I had it at my old flat and managed properly it shouldn't prove any more expensive than anything else.

Do a full comparison of rates between suppliers and try to work out typical day and night usage as best you can. Make sure you know when the switch occurs some suppliers differ.

Also consider what can be used at night and get timer plugs for them. Typical examples are phone and laptop chargers. Plug these into timer plugs that will only be set for enough hours to get 100ish % charge during economy 7 hours.

[psyclist]

I've used economy 7 for many years. The general thing to try to do is use as much electricity at night time given the lower price of units at night. So I have the washing machine and dishwasher set on timers to be on during the nighttime. Likewise a water heater if powered by electricity.

The hours of nighttime will vary by region, so you should look it up for your own region with your supplier, or it might be labelled on your meter. Generally it will be for 7 hours starting at some point after 10pm. In my area it is from 11pm.

I'm not sure 'huge bills' can be generated, but if you do use a lot of daytime electricity it can be more expensive than a non economy 7 installation.

[Kim]

Also consider what can be used at night and get timer plugs for them. Typical examples are phone and laptop chargers. Plug these into timer plugs that will only be set for enough hours to get 100ish % charge during economy 7 hours.

If you do the maths you'll probably find that the timer plug uses more power to wait for off-peak hours than the phone charger takes to charge the phone.  You might break even at a laptop, if you disregard the cost of the timer.

By all means put timers on washing machines and the like - things that actually use significant amounts of energy.  Mostly that'll be the heating of  a) water  and  b) concrete , for which you probably already have timeswitch arrangements.

The disadvantages of using a lump of concrete to heat a flat are well documented.

[Basil]

When we moved into our new house there was an economy 7 dual meter thingy.  We started to get huge bills because the timer on a storage heater wasn't working properly.  Also note that the day rate was considerably higher than that charged when on a single rate.
I got rid of the storage heater, got SWALEC to change the meter to single rate and negotiated a more sensible unit rate.

[Polar Bear]

You need to calculate what is being used on each tariff and then look at what a single tariff meter would deliver.   

We have economy 7 though it's nowhere near as good as it used to be as nighttime units are around 60% of daytime whereas they used to be one third.   In fact, looking at ours, it might actually work out a few pence a day more expensive than single rate now.

[jsabine]

My memory of back of the envelope calculations some years ago is that I reckoned it only made any sense if something like 80% of your electricity consumption was at the cheaper rate.

If the electric heating is storage heaters, E7 probably makes sense. If not, then it probably doesn't.

[rogerzilla]

I had it in my first house, which had gas heating (fires and Baxi wall heaters) and had never had storage heaters!  It was useful for the immersion until I had a combi gas boiler installed, then it was totally useless.

[Kim]

Might be worth it if you're feeding an electric car.  You probably aren't in a flat, though.

[Jaded]

It's for old people with night storage heaters who go to bed at 8:00pm.

The people, not the night storage heaters.

And as others have said, energy drains on timers.

[Diver300]

Also consider what can be used at night and get timer plugs for them. Typical examples are phone and laptop chargers. Plug these into timer plugs that will only be set for enough hours to get 100ish % charge during economy 7 hours.

If you do the maths you'll probably find that the timer plug uses more power to wait for off-peak hours than the phone charger takes to charge the phone.  You might break even at a laptop, if you disregard the cost of the timer.

The energy use of a lot of appliances on standby is much larger than you might think, especially when the manufacturers don't have to quote it. The fan in our bathroom was taking 1 W of power when off, due to the shitty design of the timer that ran it for n minutes after the light went off. In most households, that is far more energy per day than the fan would use.

[Aidan]

We are considering installing storage heaters, which for us are a possibly the best option.   We dont have gas in the village, and currently have an electric combi boil ( when its on I can visibly see my bank balance reducing!)   we aren't the right orientation for solar , and while an oil boiler is an option we arent keen on the knocking about that the installation would involve, because of the houses age, thickness of the walls etc.   So storage heaters and economy seven are first choice at the moment and would save us a shed load of money over what we have now.

[Quisling]

We are considering installing storage heaters, which for us are a possibly the best option.   We dont have gas in the village, and currently have an electric combi boil ( when its on I can visibly see my bank balance reducing!)   we aren't the right orientation for solar , and while an oil boiler is an option we arent keen on the knocking about that the installation would involve, because of the houses age, thickness of the walls etc.   So storage heaters and economy seven are first choice at the moment and would save us a shed load of money over what we have now.

Presumably you don't want to install a conventional wet radiator system because of the disruption with running pipes around the place.  That would rule out an air to water heat pump too, though an air to air heat pump system might be an alternative to storage heaters, depending on how large the property is.
https://www.greenmatch.co.uk/blog/2015/09/the-pros-and-cons-of-an-air-to-air-heat-pump
A heat pump would be more efficient than direct electric heating, and possibly allow more cost effective heating during day time tariff periods.

Sorry for hi-jacking the thread...

[rob]

Most E7 tariffs have a cheap overnight rate but a punitive day rate.   If you can move higher usage items overnight then there's a saving but you have to manage your consumption to make it work.

Some suppliers don't offer E7 but will give you a single unit rate and just charge both registers using the same rate.

[rafletcher]

If Miss C is on her own, she can probably make E7 work for her. If it's a communal flat then I doubt it's an suitable tariff.

[mrcharly-YHT]

It's just her and her husband. I've given them lots of warnings about use periods, cooking, etc. That's my main concern; their cooker is halogen and electric oven. Could be very expensive.

[SA_SA_SA_SA]

....By all means put timers on washing machines and the like - things that actually use significant amounts of energy....

Aren't washing machines quite a common source of house fires*? Perhaps only use timer to run one when you are  sleeping if it is in separate non-inflammable building ?

*Most likely appliance to cause them it seems:
https://www.firesafe.org.uk/fires-in-the-kitchen/
http://www.which.co.uk/news/2015/06/which-reveals-the-home-appliances-most-likely-to-catch-fire-406053/