What is most efficient way to run heating for my Mitsubishi Ecodan Air Source Heat Pump?

Sorry I meant its the mitzibishi Ecodan airflow heating system

Still no wiser 🤣

Is it an Ecodan air source heat pump? If it is, how are you controlling it?

Are you using a fixed flow temperature or weather compensation?

What controls do you have inside the house?

Do you have radiators or underfloor heating?

If radiators, do they have TRVs?

Sorry its very new to us and driving me crazy.

We have an airflow unit attached about 10ft up on the side of the house, all the radiators except the hallway have TRVs, and all the radiators were upgraded to bigger ones. We have no underfloor heating. 

We have a digital thermostat in the hallway it's currently set on a timer morning and late afternoon but has the option to leave on all day or use the weather compensation control which I still cannot get my head around.

We have tried leaving on all day with no joy other than expensive bills as it won't go off due to temperature in the hallway where the thermostat it. 

I believe the flow temperature was set at 55, was 45, we don't have control of this as its password protected by the housing association. 

Do you have a controller somewhere that looks like this?

It sounds like you have a fixed flow temperature, which is the worst way to run a heat pump and 55 degrees is far too high. Your efficiency will be really low, which will cost you £££

If you can change the settings to weather compensation then do this. My kid's birthday party is about to start so I can't explain how to do it at the moment. I'll be back later, unless someone else wants to help before then.

Yes we have the same digital panel just no idea how to set it correctly to get it to run more efficiently 

I’m back…

So, what’s weather compensation? Let’s start from the basics, as it’s useful to understand why something works (apologies if you already know this).

A heat pump works by moving heat from outside to inside. The electricity it uses isn’t being converted into heat, it’s being used to move the heat. The way it moves the heat affects your efficiency. As an example, you could drive your car 100 miles at 50 mph or 100 miles and 100mph. You would go the same distance but would use more petrol driving at 100mph.

You make your heat pump as efficient as possible by running it at the lowest flow temperature (you get the most heat moved for the least amount of electricity). The problem is, when it’s colder outside you need more heat so you need the heat pump to run hotter. But you don’t want it to run that hot when it’s warmer outside. That’s where weather compensation comes in. It allow you to tell the heat pump what flow temperature to use depending on the outside temperature. Hotter when it’s cold outside and cooler when it’s warm outside.

This is a link to a youtube video that explains how to set the weather compensation curve - https://youtu.be/-983aLzVZ_I

The next question is, how do you know what to set your weather compensation curve to?

When your heat pump was installed the company should have done a heat loss assessment. This is a series of calculations that works how how much heat each room of your house loses if it is a set temperature inside (normally about 22 degrees) and a set outside temperature (normally a really cold temp). This tells the system designer how much heat each room needs to stay warm and how big a radiator each room needs. If they’ve done this correctly every room should have a radiator that is exactly the right size to keep the room at your required temperature with a given flow temperature (or fairly close to the right size). This means that if set your flow temperature exactly right it will keep the house at the right temperature without any need for any other controls. You can get rid of the TRVS and room thermostats… well, not get rid of them but open the TRVs fully and turn the thermostat up high.

By adjusting the weather compensation curve you are searching for that sweet spot where the flow temperature is exactly right to keep your house at the right temperature. It might take some playing around to get it there but most people suggest making a small change then allowing at least 24 hours to see if it’s right before making another change. You might have to adjust the temperatures at the end of the ranges at different times of year, when the weather is coldest and in the spring or autumn.

Lots of people like their house to be a bit colder at night so I think you can set the system to drop the compensation curve down a couple of degrees overnight. I don’t know how to do this so I’m hoping someone else on here can help. If you want your house cooler during the day and only warm in the evening you could do the same thing.

You might notice that the heat pump runs more if you use weather compensation mode. But it’s running more efficiently so should be using less electricity overall.

Here are a few more videos that might be useful:

A guide to the heating modes - https://youtu.be/RX31v4NoQf4

A guide to using the controller - https://youtube.com/shorts/MI_OHZwenBE?feature=share

As I mentioned, your aim should be to make the heat pump as efficient as possible but you can only do that if you know how it’s performing. To work out how efficient your system is you need to calculate the Coefficient of Performance (COP). This is how much heat you’re getting for each unit (kWh) of electricity. The controller will show you how much electricity your heat pump has used and how much heat it has generated.

Press the right hand rectangular button to get a screen with these figures on the right hand side. It shows the figures for the month. Divide the heat by the electricity to get the COP.

If you press the right hand button again I think you get to a screen that shows more energy monitoring figures.

Thank you, I will give it ago but will moree than likely end up ringing mitzibishi tomorrow as its just so complex, frustrating as I am tech savvy but this is a whole other ball game to me.

We had a pressure test done in the house just in one room and all doors/windows had to be closed, afterr that a guy with a clipboard saying how big radiators were going to be.

I'll keep trying to make sense of the video and pray I can get it more efficient ass it's costing £300pm for a 3bed semi. 

Hello! Im new to this group and would like advice if anybody knows/can help. Bought a house with ecodan ashp and am trying to sort it out…. Have set flow temp to 49 after reading blog after blog and have set the weathet compensation curve as per a chap on a you tube video … my question is.. do you have this running on ‘play’  constantly or do you set the timer? I want 6am-10pm 20 degrees but 18 at night… do i set this as normal?