Changing from Eco 7 Storage heaters to single rate Electric heating but what and why????

mnbvcxz

Quick thoughts,
 you don't mention hot water. Perhaps you have an instant electric shower? Otherwise a reason to keep economy 7.

You are right economy 7 is not necessarilly worth the extra you pay for day time rate. Do you save enough at night to come out ahead? If a well insulated flat with limited occasional heating needs you could theoretically be better on a single tarriff. Economy 7 is less of a deal than it used to be too and with variable renewables unlikely to improve. Tricky think to calculate really. 

In theory you could experiment and get a £20 plug in 2kw electric heater and an electricity monitor, turn off the night storage heater and use the portable heater instead. It would give you an idea of how much peak rate electricity you need to keep your desired temperature. Work out what you would save if you have shifted that head from economy 7 period at say 90% efficiency. Tricky to do as we enter summer though...

Obviously if you did go for peak rate basic electric heaters it would cost more than £20. A Lot 20 hard compliant hardwired wall mounted heater might be £200 by the time you had installation...

Modern storage heaters should lose/leak less heat during the night but are expensive and require a second electricity cable so can cost over a £1000 once installed. The save choice though.

Brave early adopters try air conditioning units as heaters, 3 units of heat for every one of electricity, in theory they are cheap and quick to run. Need a hole through an outside wall though and will the other flats mind a whirring box on the ground outside? Installation cost is the main drawback, basically double the purchase cost, though you might get lucky with someone.  This sort of thing https://www.orionairsales.co.uk/daikin-air-conditioning-ftxm20n-wall-mounted-20kw7000btu-inverter-heat-pump-r32-a-240v50hz-6518-p.asp People seem pleased with them but the jury is still out on how wel they work in practice for heating in the cold.

I got my last storage heater parts from http://www.storageheater.co.uk/creda-1/79047-to-79144c/79047-79065/79055.html who seemed to be the cheapest. Turned out I needed a new thermostat to stop the thermal fuse going. You are right though they don't last forever though a clever person might be able to canabalise one to fix the other?

Mk1MR2

coffeehound said:

The naming tends to relate to the total stored energy which is the 18 kWh.

Thanks for that. Glad i asked since was pricing up a couple 2.5kW heaters.

Mk1MR2

My hot water is via a emersion heater so probably better to set the timer to only heat water in between the Eco 7 times and just put it on few hours before bath for quick reheat?

Gerry1

Mk1MR2 said:

My hot water is via a emersion heater so probably better to set the timer to only heat water in between the Eco 7 times and just put it on few hours before bath for quick reheat?

It's pointless having E7 and then using expensive daytime electricity (which is even more expensive than single rate) for the immersion heater, it completely defeats the whole purpose.  Just make sure the hot tank is well lagged.

If you really want to save energy, use a local timer to switch on the immersion heater about a couple of hours before the end of the cheap rate period, tweaking the charging period so that the hot water only starts to run out at bedtime.

You won't lose much heat from then until 5am or whatever, but the savings will be barely noticeable, and it may even  cost more when you factor in any changes to the wiring or buying a timer.  There's also a risk that the timer won't always match the meter times exactly.  For most of the year the leakage won't be wasted because you'll have a warmer bathroom.

Mk1MR2

OK from now on I will be setting my Fortic Tank timer to only heat water from 02:00-06:00 Hrs and just ordered some pipe lagging and hot water cylinder jacket so hopefully that way I’m making best use of the Eco 7 and still have hot water for a bath at night.

ann_droid

Hi

mine is set for 2 hours (5:30 - 7:30 AM), and it takes an hour to provide enough for a shower etc, so it can then top up in the last hour.

Perhaps you can set your start time for 4:00 am and finish at 6:00 am.

Reed_Richards

Mk1MR2 said:

...hopefully that way I’m making best use of the Eco 7 and still have hot water for a bath at night.

ann_droid said:

... it takes an hour to provide enough for a shower etc, s

We're comparing a bath taken at night with a shower taken first thing in the morning.  The bath will likely require a lot more hot water and the water in the cylinder will have had all day to cool down so may have needed to be made hotter overnight.  It's easy to see which will be more expensive.

coffeehound

Mk1MR2 said:

OK from now on I will be setting my Fortic Tank timer to only heat water from 02:00-06:00 Hrs and just ordered some pipe lagging and hot water cylinder jacket so hopefully that way I’m making best use of the Eco 7 and still have hot water for a bath at night.

Is the tank an old bare copper one?  If so it would be worthwhile to upgrade to a new one with thick insulation which (along with insulated pipes) will avoid worries about losing temperature during the day

luvchocolate

Heat mine 4 hours through the night...enough hot water for a full bath and washing up in the evening after work 

matelodave

Working out how much energy it takes to heat water is pretty simple - you can use this calculator https://bloglocation.com/art/water-heating-calculator-for-time-energy-power

However for a really simple rule of thumb it takes around 3kwh to heat 50 litres of water by 50 degreesC( ie from a cold of 10 to a hot of 60). A modern well insulated hot water tank of around 150 litres will therefor take around 9kwh or three hours to heat from cold. Even a tank with super duper insulation wil lose around 1.5-2kwh a day if it's kept hot all day. An old tank with a manky jacket will lose a significant amount of the heat that you put into it. So make sure the tank is well insulated and only heat as much as you'll need for the day so there's not much hot water left when you go to bed.

TBH the best time to bath and shower is in the morning when the tank is nice and hot after heating on off-peak leccy. Using the boost setting for an evening bath will cost you extra as you'll be using peak rate energy.

You can also work out how much hot water you use taking a shower or a bath - measure the flow rate of your shower  (many showers can deliver 10-15lpm or more), time how long it runs for when you are showering and multiply the two together 

If you assume that you mix 60C hot with 10C cold in a ratio of 30% cold to 70% hot (to give you  a shower temp of 42 degrees) then you can work out how much hot water you use and therefore how long it needs to be switched on. You can do the same with a bath, most baths are around 70-80 litres and could use around 50-60 litres of hot water (ie 3kwh worth). Multiply that by the cost per kwh and you can see how much a bath or shower is costing you. A luxurious 10 minutes under a deluge type shower could easily empty your hot water tank

My shower delivers 6lpm, I spend two minutes in there so I use around 12 ltres at 45 degrees (we dont heat our tank to 60)