Economy 7 to Air Source Heat Pump

GillianGrant

Hi

We have just chaged from an ancient inefficient Economy 7 comfort meter which cost us £200 a month to run. We were tied to Scottish Power as they falsely claimed we had 2 meters. We have now used a government scheme to install a renewable heating system with an Air Source Heat Pump as of mid Nov 2018. We don't know how to accurately get a new tariff as we are due a change of meter in the next couple of weeks. Our usage is specifically in line with our old system so we can't currently get accurate figures going forward and I wondered if anyone else had experienced this and could offer any advice. We do also have solar PV panels which are linked in now so that will also alter our figures as it didn't work with the old system. Any ideas?

matelodave

A lot will depend on how you use the system.

We've got an ASHP and I reckon that about 80% of our energy use would be at the peak rate if we were on an E7 tariff so I've opted for the cheapest single rate tariff that I can get.

We are at home all day and the unit chunters away with a flow rate of between 30-40 degrees depending on the weather (it's got weather compensation). The room stats (we've got eight) control the temperatures in each room and turn the system down by a couple of degrees overnight so we don't use much energy during the "off peak period except when it's really cold outside.

Because of the low flow temperatures it takes a long time to reaheat the house so we dont let the place get stone cold (we did once and it took two days to get back up to temperature). The stats have a holiday function so we ensure that if we go away in the winter we start up the heating the day before we return

The hot water tank is heated by the ASHP between about 7-9am but it only uses betwee 2-3kwh of electricity. We heat the water to 45 degrees which is plenty hot enough for the pair of us and there's enough hot water (200l tank) for several showers and all our other requirements. It gets a boost to 60 degrees once a week to sterilise the tank.

Most of our energy usage is during the day - I'd have a real problem persuading my wife to do washing, drying etc between midnight and 7 am. The dishwasher tends to get put on when we go to bed but thats about it so E7 wouldn't work for us.

Likewise our energy consumption profile means we use around 70% of our annual consumption between November and March when the days are short and the sun doesn't shine all that much so I feel that solar PV wouldn't do us much good either so we haven't bothered.

I reckon to use about 250-300kwh a month in the summer increasing to approx 1100-1200kwh/month in December, January and February - thats our total use, heating, hot water, cooking, washing, drying etc etc. Not much washing gets onto the line it's virtually all tumble dried.

I've got an energy monitor which shows my consumption in real time and also graphically - see here https://www.energyhive.com/dashboard/dave and you can see how it varies. The ASHP is very sensitive to weather conditions and I can tell when it's been colder because it uses more energy.

Terresa

GillianGrant wrote: »

Hi

We have just chaged from an ancient inefficient Economy 7 comfort meter which cost us £200 a month to run. We were tied to Scottish Power as they falsely claimed we had 2 meters. We have now used a government scheme to install a renewable heating system with an Air Source Heat Pump as of mid Nov 2018. We don't know how to accurately get a new tariff as we are due a change of meter in the next couple of weeks. Our usage is specifically in line with our old system so we can't currently get accurate figures going forward and I wondered if anyone else had experienced this and could offer any advice. We do also have solar PV panels which are linked in now so that will also alter our figures as it didn't work with the old system. Any ideas?

If you mean you had a Scottish Power Comfort Plus meter, that was a 3 rate tariff .

Most other suppliers would not accept you with that type of metering, so whether or not you considered the information provided by SP to be false, it was well intended.

What type of meter do you have now?
Because you start the post saying the meter has been changed, but go on to say you expect another meter in the bext couple of weeks.
If you still have the Scottish Power Comfort Plus meter, you should not attempt to switch supplier until this is changed.

No one here can tell you what your consumption will be based on the limited information you have provided. One would hope you had considered your expected energy use before you splashed out on a high cost, somewhat specialised, heating system.

I would suggest, in the absence of any better figures, you use figures suggested to you by a comparison site - but keep a close eye on them to see whether you use more or less than this.
If you are using significantly different amounts, then do another comparison with such new figures, and be prepared to switch if necessary.