Economy 7

[johnnyjb]

Hi i was windering is there different types of economy 7.Some places i seen have a seperate board and some dont.Can you get economy 7 to supply all your house , apartment ect.. or is it just for the heating element of the premises or is it a bit of both ??
Thanks

 

[Steve]

When economy 7 kicks in, it makes the whole supply low rate.

Most supplies also have a set of contacts which can enable a second DB, which you would use for storage heaters.

This can all be done in a meter now, no teleswitch required - the meter has it built in.

On eco7, most suppliers will not fit it unless you have excessive night use (storage heaters, pool heater, aviary, LINAC etc), or else your bills will increase. This is because although the night rate is cheaper, the day rate is more expensive.

 

[Stoday]

Suppliers will provide you with Economy 7; it's up to you to check if it's worth it or not depending on your night use.

No supplier will refuse because:

1) you could choose another supplier and

2) If, in the event it would have been cheaper for you, the supplier could be liable.

3) The supplier cannot forecast your next year's consumption to know what your night proportion will be.

 

[ericmark]

Economy 7 is a tariff. How it is used varies. Somewhere there will be a method to work out at what time the power is used. This was originally done with a white meter and the two supplies were separate. But then it was combined and each appliance had it's own timer so Washing Machines, Tumble driers, Dish Washers, Immersion heaters could all take advantage of the cheap rate power. There was also an Economy 10 which had a day time period to boost the storage heaters.
Large consumers factories and the like with offices attached found the use of storage heaters very good as they could run on a smaller supply. But for houses it did not work very well as by time people arrived home there was very little heat left in the old bricks.
There were some bulk storage units which look like normal central heating and the heat was stored in one central unit. These worked a lot better.
So the answer is no there are not different types of Economy 7 but there are many types of storage systems, tariffs and control methods. So to be less pedantic the answer would be yes as I would think you were referring generally to storage system rather than one tariff type.

 

[flameport]

The only time you want E7 or E10 is if your entire heating system is electric - so storage heaters in every room, immersion heater for hot water, or one of those hideously expensive central heat stores.

Waste of money otherwise.

Even with an electric immersion heater for all the hot water, it it still not worth it - heating a hot water cylinder overnight simply won't use enough energy to offset the increased price for electricity in the daytime.

 

[Lectrician]

Economy 7 is a tariff. How it is used varies. Somewhere there will be a method to work out at what time the power is used. This was originally done with a white meter and the two supplies were separate. But then it was combined and each appliance had it's own timer so Washing Machines, Tumble driers, Dish Washers, Immersion heaters could all take advantage of the cheap rate power. There was also an Economy 10 which had a day time period to boost the storage heaters.
Large consumers factories and the like with offices attached found the use of storage heaters very good as they could run on a smaller supply. But for houses it did not work very well as by time people arrived home there was very little heat left in the old bricks.
There were some bulk storage units which look like normal central heating and the heat was stored in one central unit. These worked a lot better.
So the answer is no there are not different types of Economy 7 but there are many types of storage systems, tariffs and control methods. So to be less pedantic the answer would be yes as I would think you were referring generally to storage system rather than one tariff type.

You talk of econ7 and 10 in the past tense, but they are both still currently offered and are appealing to many sites.

Econ7 and 10 have always provided low rate to the entire supply. It was the 'white meter' tarrif which only gave cheap lecky to the storage rads during certain times. Most 'white meter' off peak tarrifs have been changed to Econ7, this requiring a new meter. You do still see the old white meter tarrif however (every so often).

Large commercial sites will often have their own tarrif agreed, and the meter programmed accordingly - It is not uncommon to have 4 or 5 rates during a 24hr period. You usually have a 'customer presentation box' which has volt free contacts in it for each rate, and you can then use these to switch off-peak loads as required. (obviously via contactor).

A site we work at has a very good tarrif with 4 rates during the 24hr, the rate from midnight through to 5am being extremely cheap as this is the time their largest demand is. We use this rates output to heat the storage rads and water, and then give the site a boost on the afternoon tarrif for the night shift.

It gets a little involved. You have one supply, the rates apply to the entire supply. You use the rates volt free contacts to operate contactors as you need. However....this site also has a backup genset, and this takes over the entire supply in the event of power failure. It was decided as the genset was large enough that the storage heater load should also be driven by the genset, so there are some relays prior to the contactors to enable to the genset to take over control of the contactors (although it does not dictate rates, it just supplies constantly).

On large sites, it is common to run a large submain (circa 600amps) from the mains intake to one building for example. You then have an econ7 TP DB in that building, with it's feed from the submain (constantly live). You then switch this DB via a contactor, the contactor being supplied via a cheap run of 1.5mm SWA or similar (run along side the submain). You don't want to go running in large SWA's just for the Econ7 loads.