We are lucky that we live in a cooler area of the country and our 1700's stone cottage is like a cave so the bedrooms stay reasonably cool. With careful management, not opening windows and keeping blinds shut, we have managed to keep to room temperature down to 20C in the bedrooms. Our main living space has been more challenging though, and has been 26C.

If I lived in the south east and needed AC, I'd be looking at one of these portable split units, like this one from Midea:

https://www.midea.com/uk/air-treatment/porta-split

I've seen a few reviews and from people who have one, and they are a lot more capable (and efficient) than the large hose through the window types.

Either that, or A2A for both heating and cooling would be the ideal solution in hotter areas, but then you have the issue of what to do for DHW.

Good question

I have aggressively managed window shading and opening/closing times.  Most of my windows have Low E glass or better and Go Outdoors sell a survival blanket for £6 (£3 if you are a loyalty club member) which has proved very good for the oly sunny one that doesn't.  The guy in front of me at the checkout was buying some for the same purpose!

I have also fired up the heat pump in (above dewpoint) cooling mode and run our portable dehumidifier.  I have one fan coil and two radiators with add on computer fans, not really a lot to provide a load or much cooling, but a start.  My feeling is that it has taken the edge off, but its far from true aircon.  The fancoil is noticably more effective than the adapted radiators.  The heat pump cycles because of the low load, which Im pretty sure reduces the effectiveness, because its only below 20C (the ceiling temperature for the fancoil) for part of the time.  I have tweaked one control parameter which has helped a bit, I have probably run out of time this time round to do much more tweaking.  More than even I now wish I had bought a few more fancoils for the rads that were marginal!

The heat pump is reporting just over 5:1 ratio of cooling to electricity supplied, however I suspect quite a bit of that goes towards cooling the outside given the cycling.

Here are some plots

IAT in the 'sunroom' (the clue is in the name).  This has the fancoil in one half of the room, the sensor is in the other half.  The very slow reaction time of the house is very evident in these plots.

OAT on a north facing shaded wall

Humidity ditto.  The drop towards the end is because I started running the dehumidifier on half power 24x7, rather than full power overnight.

FT, obviously including some DHW cycles.  The Heat pump is on 7.30am-7pm only.  The change in dehumidifier operating mode is also manifested here.  Before running it constantly the FT used to creep up during the day, because the heat pump was adjusting to an in creasing humidity by increasing its target FT.  On Thursday you can see that this did not occur.

Power consumption

@old_scientist looking at the photos, you still need the door/window ajar for the Midea unit, but it does look tidier than what we presently have.

Posted by: @editor

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@old_scientist looking at the photos, you still need the door/window ajar for the Midea unit, but it does look tidier than what we presently have.

Yes, I guess unless you have a professionally installed unit, any portable AC unit is going to require some connection between inside and outside units.

The umbilical linking them is quite thin (as opposed to large air vent hoses), and I've seen some reviewed with Velcro sealing kits to go around a door or window to seal and stop warm air entering.

These units are apparently a step up from the type you have and sit somewhere between what you have and a professionally installed A2A unit, both in terms of performance and price (somewhere in the £750-£900 range I think)