Sunday, 24 June 2012

Economy 7 Tariff & Solar Panels.

I've been surprised at the number of people who have commented or emailed me regarding the potential savings if "Energy 7" tariff were used in conjunction with solar panels.
The lure of electricity charged at 25% of the daytime tariff has always been a powerful incentive for consumers to run their appliances and storage radiators between midnight and 6-7am. The addition of a timer on many white goods makes this relatively easy to achieve.

As you can imagine, this is not a "one size fits all" scenario. Everyone has different needs and circumstances. I've attempted to give an indication of how a change of tariff would affect my energy usage and payments. The link to the data spreadsheet will give the figures I've used and may be altered if you want to experiment with YOUR information. Link to tariff comparison spreadsheet.

Despite the best efforts of the energy ombudsman & Ofgem, it's very difficult to compare tariffs from different companies. The "Big 6" energy companies are fighting the proposals to make the process simpler. (Surprise, Surprise.) Report on moves to simplify tariffs.

All of the companies offer a 75% reduction in price for electricity used during the 7 hour night-time period. You should be aware that the package prices electricity used during the day with a 25% increase on "standard" electricity rates.
You should also be aware that if you don't currently have a energy 7 meter your supplier may charge you for the cost of the meter and its installation. EoN state clearly on  their website "it's at your cost." 
When I called my supplier (npower) to ask about costs I was told "if you need it we'll install it FOC." Whilst I have to accept the information given, npower have a history of getting things horribly wrong.... Check before signing anything.

Npower offered "Bill Saver 2013" as their most economical tariff for me based on an June 2012 enquiry.

Electricity                        @ 13.493p kWh.
Electricity standing charge @ £26.28 p.a.

Gas                                 @ 2.755p kWh.
Gas standing charge          @ £211.34 p.a.

Npower "Economy 7" tariff based on an June 2012 enquiry.

Day-time Electricity          @ 16.034p kWh.
Night-time Electricity        @ 4.757p kWh.
Electricity standing charge @ £73.20 p.a.

Gas                                 @ 2.755p kWh.
Gas standing charge          @ £211.34 p.a.

Which appliances can you use at night?

I suspect that there are relatively few people now who have storage radiators?    

I have gas central heating, but if the technology had been available at the time I wish I'd installed an air or ground pump system warming underground cables. This is wonderfully efficient system and after the initial instillation costs, very cheap to run. Link to Air Pump information.

I've discovered a very interesting site which allows you to select specific manufacturers appliances to establish their energy costs per cycle or in the case of fridge/freezers cost p.a.       Link to appliance energy usage site.

In my case I'm not sure how we could take advantage of the night time tariff other than using the washing machine, dish washer and tumble dryer exclusively at night.
The energy usage which shocked me most was the Fridge-Freezer. It's not an appliance that you can easily make economies with, which runs 24/7. Mine uses a massive 310 kWh's a year, that's 12% of all the electricity I use is involved in keeping stuff cold....

Based on the tariff data I've received, there doesn't seem to be a valid case for me changing to economy 7, projected cost £856. My family size & lifestyle makes the standard tariffs more attractive, projected cost £822. It might be different if we heated our home or water with electricity.

If You're using Economy 7, or have arrived at a different conclusion. I'd be very interested in your comments.

Twitter: (@solaricarus)


  1. Hello, this is Nick who commented on your previous blog entry which led to this posting.
    Regarding economy 7, it looks worth it to us at the mo' because we have an electric shower (ouch, at 7.5kw they really should be illegal, makes a mockery of phasing out incandescent light bulbs.. but I digress). So having a shower before going to work still is in economy 7 time. We plan to get solar thermal installed which probably never pays for itself, using hoped for profits from our PV system. Once we've done that, and ditched the electric shower, as you say the only thing you can run at night is appliances. So then its doubtful if economy 7 is worth it. In fact, is economy 7 really a big con for most people?
    About your fridge/freezer - that doesn't sound bad per year , probably still A-rated? You can buy a Bosch one thats A+++ which uses half the power but it costs a fortune to buy up front. Its well known that refrigeration is one of the biggest parts of the electric bill - single most thirsty appliance overall I suspect. But presumably this is where solar PV helps the most. Its those many hours on cloudy mornings or evenings when your solar panel is just covering your fridge's 60w motor, that really adds up to bill savings.
    PS - Tumbledryers are also the work of the devil IMHO. Lakeland sell low energy very slightly heated laundry racks. They're intriguing - don't know if they're any good. Their Remoska cooker intrigues me too in conjunction with a solar panel, but I'm not sure what it really saves either. Maybe something else to look into

  2. Hi, I havent done the math yet but I assume as we have no gas (live out in the sticks) and everything in the house is electric, It would suggest that it would be worth changing to economy 7 in our situation.

    As mentioned fridge is on 24/7 and cooking is done during daylight hours but we have just installed solar to try to reduce daytime usage.

    We have a ground source heat pump that when on uses 2.5KW per hour (when its starting to get cold this is mainly during the night and in winter almost 24/7). The GSHP also provides our hot water. We could easily adapt to using the washer, tumble drier and dishwasher at night through the use of inbuilt or external timers or I can put it on myself as I work shifts and Im awake a strange times some times during the week

    1. Hi janz70.

      Very interesting points made in your comment.
      I'd be VERY interested in any information you have, or would be willing to help you research the options regarding economy 7 and heat pumps.
      I decided that the economics didn't work for most people, but you may be the exception to the rule.

      Could anyone else who can help on this, please leave a comment or email me direct at


  3. It really does come down to taking each property on its own merits. I have an electric airsource heat pump which is supported by a log burner with a back boiler. 4kw of pv brings in a percentage of our power during the daylight hours and economy 7 kicks in at midnight during the winter. The expensive point is when the sun goes down until the cheaper electricty comes on line. No tumble dryer or dish washer and a washing machine with a delay setting helps out.

    Its definately worth doing if you have the right combination of heat sources and appliances.

    1. Hi Tim.
      As I mentioned in my piece on economy 7, there is no "one size fits all " solution. I suspect that for the majority of people the increased cost of daytime electricity makes it uneconomic, but if you have electric underfloor heating, particularly powered by a heat pump a different picture emerges.
      I envy your self sufficiency and probably your fuel bills as well!

  4. Hello I've just had a chap in to talk about the new Quantum storage heaters by Dimplex. We've been going around the houses with ideas to replace an old oil fired central heating system. We've looked at air heat source, bio mass but have hit a hurdle as we took out our oil system 2yrs ago ( we've just been relying on electric immersion for hot water and a wood burner in the lounge with some occasional small electric heaters, hot water bottles and blankets for keeping us warm in bed! for 2 winters) but have just been told by the guy doing our energy certificate that this means we won't be eligible for the full RHI rates which is what would have made the bio mass option affordable! So hence me looking into these Quantem heaters. We are definitely going ahead with solar voltaic panels and possibly solar thermal too to cover the hot water. I've been trying to work out whether we should change to economy 7 to use the Quantem heaters which look like a cost effective option in terms of capital cost but need to work out running costs. Ideally they look like they'd be a good option with solar panels heating up in the daytime using up the electricity we generate but I don't think they do this! I think if we do go onto economy 7 they'll heat these energy efficient storage heaters on the cheap rate at night and the electricity we generate in the daytime will cover the cost of the electric we can use in the daytime like household appliances and computers etc that we use running our office from home. We're not on economy 7 at the moment but we are with npower. Just done a price comparison on what we pay at the moment and we should change on price grounds!

    1. Hi.
      I've posted a reply to your comment on the main website.
      I'd like to have been more positive, but I could find only 2 positives compared to 6 concerns. Perhaps once you've decided you could give us some details as to what influenced you?