Economy 7 and Hot Water

1dMeredith

Please can anyone help? I live in a 1 bedroom flat with Economy 7 electricity rates.  My current Economy 7 water heater only heats water with the boost.  I want to replace it with something efficient and have looked into Fischer Future Heat's Aquaficient system, but it is very expensive.  I've been searching for a less expensive alternative that offers the same instant hot water from stored energy charged during off-peak time,  but I can't seem to find anything.  Is there such a thing? Thank you!

Robin9

The usual E7 hot water heater has two elements - one at the top of the tank (the boost) and a second at the bottom (which comes on a night) and there will be two switches.  Are you sating you only have one element and one switch.?



If you do have two then bring  - first check the switch for the bottom element  is on. If it is bring   in an electrician - far better to repair what you have

Reed_Richards

Immersion heaters are 100% efficient in heating water but the water cylinder will lose heat over time, less quickly if it is better insulated.  The surrounding pipes also need to be insulated.

The "Fischer Aquafficient" is a thermal store which stores heat in a phase-change material then uses that to heat water instantaneously.  The main advantage that I can see for this type of technology is that it can be made more compact than a water cylinder for the same amount of stored heat so it is good when you haven't got room for a hot water cylinder.  That's not you @1dMeredith , you already have the water cylinder.  And because you get a tank full of expensive phase change material instead of a tank full of cheap water those things are costly.  And it is a tank full of hot material so it will lose heat over time too.

I agree with @Robin9 , your best option is to fix what you've got.  

Tallerdave

Replacement immersion heater elements are £20-30. Getting an electrician to fit it, maybe double that? Your bank account will thank you!

Gerry1

Don't forget the obvious things e.g. lower immersion heater switched off locally, E7 circuit has tripped out at the consumer unit, timeswitch is stuck in day mode etc.

tastyhog

Immersion tanks are pretty efficient as far as having stored hot water are concerned. 

If its got two elements and one isn't working, and the other is running off the E7 circuit it's highly likely its just the thermal cutout switch on the thermostat that's tripped.

Turn off the electric at the mains, remove the black cover on the thermostat, most likely the bottom one if the boost is working, which usually uses the top one, that's not working and you'll see a little reset button on it somewhere, just push it in and your tank will likely heat up overnight.

Whilst you've got the cover off increase the temperature to 70 if it's not that high already, it'll retain its temperature better and depending on how much hot water you use will cost less to heat on a day to day basis. 

Reed_Richards

tastyhog said:

Whilst you've got the cover off increase the temperature to 70 if it's not that high already, it'll retain its temperature better and depending on how much hot water you use will cost less to heat on a day to day basis. 

I'm afraid the laws of physics don't agree.  The greater the temperature difference between that water in the tank and the surrounding air then the faster the tank will lose heat and the more it will cost on a day-to-day basis.