You really need to find a way to isolate the ASHP consumption from the total household data otherwise any conclusions will be inaccurate. 

Does the main controller have data logging or can you download an app to access data?

@george, that's a valid point. If we didn't have the RHI metres, there'd be no way we could isolate ASHP consumption from the rest of our electricity usage. Having said that, Global Energy Systems to track and provide the information for compressor consumption, so I wonder if other pumps all log and track usage.

Here is our data from March this year. Its amazing what a difference a bit of sun and warmth makes over these last few days 🤣 .

Overall we are doing better than last year and this includes running the secondary return for longer than last year for hot water. Our second log burner was fitted about a month ago so that has helped a little. 

I would love to get our hot water costs down but I'm not sure the investment on solar pv or solar thermal would be recovered quickly enough to make it worthwhile. If we build another house I would insist on having a log burner connected up to the hot water tank with a coil to heat up the water and solar for the sunnier days as I believe this would be enough to heat the water without the ASHP or immersion heaters having to kick in.

@george, decent solar is amazingly helpful. We did over 500kWh in March, and that takes some pressure off the bills. Also the warmer has helped.

I'd love to have an amount like that coming in during March as it would cover almost all of the hot water demand. Sadly I can't see us living at this house in 5 years time and when I did my maths previously for solar it was 11-12 years payback.

I also looked into a small wind turbine and was told by one installer that the small domestic units are a waste of time even though I live in a windy location.

Hi Mike,

If you just require hot water, then solar thermal would be the more cost effective solution. One or two solar thermal panels should be adequate to provide much of your hot water requirements. I assume you had a new hot water tank fitted when you had your ASHP installed, so you may just require the solar thermal panels and a water pump, plus the pipework and controller of course.

Solar PV would give you much of your hot water and would also help provide electricity to run your ASHP, but would be more expensive to install.

Having looked at the data that you provided, I would question if your ASHP is operating efficiently. Can you supply photo's of where your ASHP is located and also the control equipment that was provided with your system. I will then download the manuals and see what adjustments it may be possible to make.

Regards,

Derek.

@derek-m Derek,

From the context I think you may have meant George, but anyway here 's my ASHP and control panel. The pump is next to an outbuilding about 20 feet from the house. It's in a well ventilated area that's out of direct sunlight. Controllers are on 1st floor next to the storage tank. Grant have an app from which you can access some documentation. They are too technical for the end user (this one anyway).

I've looked at adding Solar PV. The available roof area is small, faces SE and would require scaffolding for access to install panels. I've had a quote for £6k, against monthly savings I estimate at £30, so marginal if correct.

Mike

Thanks for getting back to me on YouTube. Question posted below as suggested. 

Hello. I have recently moved into a new build with a 14kw ecodan system. I’ve read that running them all the time rather than set to come on at certain times is best... Is that right? The temp is set at 19 degrees but the heating switches on and off throughout the day to maintain that temperature. I get the feeling that’s not the best way to have things set up and it will cost more in electricity. Any help would be appreciated. Thanks.

@s-watson, it's normal for the ASHP to switch on and off.  As far as I have read, 2 or 3 times an hour is normal.  Excessive 'cycling' can be a problem but that would be much more than that.  

It is better to keep the ASHP running most of the time.  It's not like a boiler where you can switch it on and off and heat the house up in half an hour.  You might want to lower your temps at night or maybe shut it down for a short time.  But you don't want to let the house cool down too much as the lower (than a boiler) flow temperatures  will mean the house takes a long time to heat up and the ASHP will be working hard.  With a new build your house should be very well insulated so once it's up to temperature it won't take a lot to keep it there. 

We also have a 14kW Ecodan, although it's ony been in for a few days. I'm just going to leave it on and let the thermostat control it for the time being.  I am going to look into turning the hot water off most of the time as we don't use much and a few hours at night may be enough.  

Welcome to the forums @s-watson and thanks for joining.

You are correct about leaving your heat pump on 24/7 (all the time) and not on a timer. The heat pump should come on when thermostats around the house call for heat. The reason (I think) that your heat pump keeps coming on and going off is because your target temperature of 19C is quite low given that temperatures in the past week have been quite mild. In fact, we hit 20C for a few days this week and the heat pump was off during the day, and only came on in the late evening. 

You'll probably find that in the cold winter months (Dec-Feb), the heat pump will be on almost all of the time. 

Is your house well instated? Also, how many thermostats do you have around the house that call for heat?

@editor

Hello. Great info on this forum and appreciate the help. Hopefully I’ll be able to contribute in the future.

The house is well insulated. The only thermostat is the main controller that is in the main hall. There is no underfloor heating. Only radiators with manual thermostats.

I wasn’t sure what to set the temperature to. The house is an okay temperature during the day but it can be a bit cold in the morning.

I’ve read a few places that a nice steady heat can be achieved by having the pump on all the time but I don’t know enough about it to set it up for that. Also the more efficient the better as well. 

Posted by: @derek-m

Hi Mike,

If you just require hot water, then solar thermal would be the more cost effective solution. One or two solar thermal panels should be adequate to provide much of your hot water requirements. I assume you had a new hot water tank fitted when you had your ASHP installed, so you may just require the solar thermal panels and a water pump, plus the pipework and controller of course.

Solar PV would give you much of your hot water and would also help provide electricity to run your ASHP, but would be more expensive to install.

Having looked at the data that you provided, I would question if your ASHP is operating efficiently. Can you supply photo's of where your ASHP is located and also the control equipment that was provided with your system. I will then download the manuals and see what adjustments it may be possible to make.

Regards,

Derek.

 

We have 500l unvented cylinder with a secondary return running from 5am till 11pm and 7-11 people using hot water each day so we plough through it. I think my hot water data will always look high compared to most normal setups.