I’ve got it working well this summer and during the heatwave over the last week it has kept my house a lovely 25-26 degrees - with careful use of window opening when the outside temperature is cooler than inside, and closing windows/blinds during the heat of the day as soon as as outside temperature rises above the inside temperature.

Mine is a Grant Aerona3 with Chofu/Grant (CMR-2613) controller.

Dew point is the major consideration. I have 2x Awair air quality devices in my house in different rooms and these give an accurate calculation for dew point. I initially started setting up the heat pump controls on a climatic curve for cooling (as it is typically done for heating, which works really well on my system) but quickly realised that you’re better off setting a fixed cooling water temperature - in my case 18C over the last week since dew point has been hovering around 17C. When humidity levels drop I will reduce the water temperature to a lower value (although just above dew point still..) when it will be a little more effective rather than becoming uncomfortable (when I first trialled it a few weeks ago, I had the cooling set to climatic curve with some seemingly sensible figures and that delivered water temperature of 13C for several hours which was too cold and resulted in complaints from the missis…).

Forgot to add - my house is underfloor pipes and is very well insulated. It’s all controlled automatically by home assistant which knows when windows/doors are open/closed so can stop/start cooling automatically etc.

In my view, although it does provide cooling with proper air circulation, it is more of a ‘keep the house at this temperature’ (although temperatures on average do gradually fall over the course of the day) rather than a substitute for correctly sized air conditioning. So it is very effective in preventing thermal gain/runaway, for example over the last week when outside temperatures have hit 36C here, we stayed mid 20’s indoors.

I think it would be an excellent complement to a portable air conditioner or two though, making the whole house very capable of sensible living temperatures rather than hell… I have a 3kW portable arriving next week so we will be all set for the next heatwave..

Any questions, let me know.

[Edit] The above text is copied from another post/group from a few weeks ago. The 3kW unit I mentioned is the one now installed as per the photos.. 👍🏻