Underfloor heating Mitsibushi Ecodan System

Are you sure you're looking at the input power and not the output power. 10kw sounds more like the output power. For input power you should check the meter or smart meter.

I just looked at the memter again and currently sitting at 3kw per hour average over last 5 hours.

only have standard household appliances running so confident that is the main source of power usage.

That is a lot less than 10kw per hour and more like what you should be seeing. I don't know the size your property, it's insulation or your set temperature. But if your set temperature is say 21-22°c and your insulation is not great that power usage might be right.

My house is quite well insulated and set temperature is, 19

-19.5°c. You will see a spike in power during water heating.

Do you have a smart meter ​@gdebruin if you have half hour readings that will help to see the pattern of your heating plus other equipment.

Can you explain a bit more about your setup. Photos would help too please.

Also what kind of outside and inside temperatures are you talking about ?

the temp outside today was about 2-4 deg. inside I set it to 21 for under floor heating which is downstairs.  and then a second zone with radiators throughout 5 bedrooms upstairs is set to 20.  i will look at the 30 min readings as I have a smart reader but not really sure how to do this.  

I would guess about 250 sqm size property.  upstairs is one zone with the radiators and downstairs is the other zone with underfloor heating.  Property build about 5 years back so very well insulated in my opinion but it is a big place

A constant 3kwh would not suprise me 10kwh constant sounds high. Can you get figures for daily and weekly electricity consumption.

You should be able to see your half hourly usage on your energy supplier’s app. I’m with octopus, this is my usage graph for 11th dec. I have battery storage so you can see a big gap where the house was running on the battery most of the day. It is charged up during the cheaper rate window from 23:30 to 05:30

More usefully I have a monitoring system which shows exactly what the heat pump is doing. This graph is also 11th dec. The spikes are hot water heat ups. I have been running it 24/7 too. Our bungalow is 99m2, with 7 radiators, heated to 21/22 degC , it was around 7degC outside on the 11th and it used 18 kWh.

Can you see what your flow temperature is ? There will possibly be two, one for each zone.

any guide as to how to set the settings the best for underfloor heating and radiators?  My zone has 2 zones.  Upstairs radiators downstairs underfloor heating.  Its a big property and I would like to try and save somewhat on the bills.  Not sure what the most efficient settings would be in order to get me the best results?

Morning ​@gdebruin,

I’m wondering whether ​@juliamc and ​@brichard may have any more helpful advice around this? I must say heat pumps aren’t my area of expertise. In the meantime I just wanted to link you to these previous Forum topics which you might find helpful:

​@Ben_OVO ​@gdebruin has another thread: 

which shows photos of their system, the main thing that M.isterW pointed out is the third party thermostat which will reduce efficiency. Best approach is to run the system using the Ecodan controller with weather compensation and not this thermostat control.

I have only had my heat pump since the end of November but I have spent a lot of time thinking about how to get the best out of it. My house is mainly 1930s construction, quiet large with 18 radiators mostly upgraded, solid brick in many parts with external insulation. Temperature set for 19c fully weather Comp.

My worst day was the 10th January where I used almost 60kwh. It was very cold and damp that day and I had no nighttime set back. My best day was February 21st where I you used 10kwh. COP YTD 4.2 which I am very happy with.

I don't think the electricity usage you are seeing is too bad and over a whole year should work out comparable or better with gas. I'm still playing with settings but currently set back to 16.5c from 10pm and ramping back to 19c at 5am. I'm also playing with water heat settings. Currently once per day at 1 pm. Water temp set temperature 45c. We have never run out of hot water despite the temperature showing only 12c on the tank thermostat. My plan is to keep turning the water down until I get complaints.

In general I'm spending more than when I had a gas boiler but with the boiler the house was cold most of the time now it's warm all of the time. To heat the house to this comfort lever with gas would be much more costly.

Hey ​@gdebruin 

brichard & juliamc have given some helpful responses here. Just tagging you so you don’t miss them 😊