unvented water heaters

continualdiamond

To me i seem to be paying a lot in electricity and can never work out why. Recent bill said this:

primary units used- 182 cost 12p
secondary units used - 1036 cost 8.62p
night units used- 1590 cost 3.14p

I can't work out why i used so much electricity during the day. I am out from 8am until 5pm. My bf works shifts, could this be the problem as the house doesn't go long without someone home.


ie. Shift 1 - 6am - 2pm, so hes hm from 2:30pm
Shift 2 - 2pm - 10pm, so home until 1pm
Shift 3 - 10pm - 6am, home from 6:30am


or could my water heaters be the cause. I actually don't know where they are, i just looked in my loft and its so tiny you can't actually go in, i can see 1 on switch for something. Anyway i found the instruction manual for my water heaters.

30 and 50 litre unvented water heater - electrical rating 2.75/3kw 230/240v
or 0.9/1kw 230/240v

10 and 15 unvented water heater - electrical rating 2.75/3kw 230/240v or 4.1/4.5kw 230/240v

Does the above numbers mean a lot? If not im really stuck to why day electricity is so high.

Any ideas??

caveat_emptor

Assuming your bill is for a quarter your total day usage is 1218kwhours.
Not all your electricity is going to water heaters but let's assume it is.
If your water heater is 1 kw then it's on for 1218 hours/quarter or 13 hours a day which is unlikely. If your water heater is 4kw then its on for 1218/4=304 hours/quarter or 3.5 hours/day which is more likely.
Your night usage is 1590kwhours/quarter or 17 hours/night which is impossible for economy 7. If heater is 4kw then it's on for 1590/90/4=4.5 hours/night.
Hope this helps

Bri_2205

There are still 8 hours around your 'out of house' times that the daytime rate applies to. I'd imagine you would be more active in those 8 hours than from midnight-7am normally

paul_h

Unvented water heaters are notoriously expensive to run, as they are using peak daytime electricity to heat your water - it's like boiling a kettle each time you turn on the tap.

They are quite small and are often mounted underneath kitchen sinks or in cupboards, etc. - if there's one in the loft it will most likely be for the bathroom.