Economy 10 - Debunked?

MountainMan101

I've been planning on installing an electric boiler (CH only) and going on E10. I'd done some calculations to estimate usage, and convinced myself of the benefit over oil (mostly in setup cost and garden space). However, I've just compared my theoretical usage on E10 with the latest BG Click 5 prices (all before any discount for direct debit etc).

Usage:
3.5 units day rate (lights, cooking, etc)
6.5 units cheap rate (ie during E10 periods - 9kw electric shower, washing maching, immersion heater)
Estimated 60kwh electric heating (based on comparison with similar houses)

E10:
3.5 units would be at 12.7p + 20p standing charge
66.5 units would be at 7p (E10 rate). However this means heating 3-5am, 2-4pm and 8-10pm but nothing between 4 and 8 pm.

Estimated cost for 3 winter months : £450

British Gas single rate:
500kw @ 23.5p, the rest 7.4p
Which means ~68.5 units at 7.4, + ~1.5 @ 23p
Heating could be 4:30-6:30am (before getting up) + 3-10pm (with temperature set to use power ~50% of the time).

Cost for 3 months : £460

However, the real killer is that with E10 every hour outside the cheap zones is mega expensive £1.20 per hour (10kw boiler).

So basically, what I'm getting at, is that anyone with E10 and and electric flow boiler should check out their actual usage and compare with current single rate prices.

The same doesn't apply for the other types of Economy 10 (heatwise, warmwise) that use a separate circuit to power storage heaters. I don't know enough about those to compare things.

Philip

PS In all cases above, by E10 I mean Scottish/Southern Economy 10 tariff with cheap elec for all circuits 12-5am,1-4pm,8-10pm.

peat

You can use a thermal store system and only heat the water in the store at cheap rate times. Try doing a search on this forum for wet electric central heating for more info.