Air conditioning new building experiences?

Hello everyone,

I built a new house 4 years ago and have the problem that the bedroom upstairs gets very warm in summer (when it is warm/hot for several days in a row).

Accordingly, I am looking for a suitable split air conditioning system.

The bedroom is about 18m² in size -> correspondingly just under 50 m³ room volume.

It would be desirable if I could also control the system with my phone (+ schedule). It would be really nice to have the option to connect it to ioBroker.
I have an HVAC technician available who can install the system for me.

I have the following questions:

- I have a controlled ventilation system installed. How does this behave in combination with a split air conditioner? Do I need to consider anything in this regard? There are two connections in the bedroom (1x supply air and 1x exhaust air).
- In the adjacent room there is a children's room (about 20m² -> about 55 m³ room volume). Does it make sense to switch to a multi-split system right away so that I can possibly cool both rooms with one outdoor unit? Actually, I do not currently need cooling in this room, but it is possible that we will decide on this in 1-2 years. Or can I just as well buy a single split unit later?
- Should the connection between indoor and outdoor unit be kept as short as possible? For example, I wonder whether the outdoor unit should be installed directly at the top of the gable or if I can also install it down at ground level (there is a garden there, so the unit would be a bit more "hidden" [IMG alt=":)"]https://www.kaelte-treffpunkt.de/images/smilies/icon_smile.gif[/IMG]).
- Main question: Which air conditioning system can you recommend for my needs/requirements? I am mostly looking for the best price/performance ratio.
- I am happy to buy online – I have read that air conditioners are significantly cheaper in Italy. Has anyone had experience with that? How does it look with warranty/guarantee and customs?

I hope that I can get some questions answered here [IMG alt=":)"]https://www.kaelte-treffpunkt.de/images/smilies/icon_smile.gif[/IMG]

Best regards
Markus

1: You don't have to worry about the ventilation system. 2: Two single-splits are cheaper, more efficient, and more redundant than a multi-split. The only disadvantage: two outdoor units. 3: No. Often even 3 meters are specified as the minimum distance. 10 meters is no problem. Beyond that, it often needs to be refilled, but that's not a big deal either. 4: The usual suspects: Mitsubishi, Daikin, Panasonic... each time the weakest ones they have (2-2.5 kW). Look through the datasheets to see which meets your requirements for remote control. They are all suitable. 5: Yes, Italy works well. There is no customs duty. Warranty only through the manufacturer, though. Problem: You have to find someone with a refrigeration license to install it for you. Alternative suggestion: Is there perhaps a central spot, preferably as high as possible, where you can install an indoor unit? If you do that, then turn the device on BEFORE it gets too warm, leave the doors open, and just let the device run, you will have all rooms comfortably cooled and the device can really deliver its performance into the house. A 20 sqm new-build room is, in fact, too small for almost any device. The general rule is: runtime, runtime, runtime. Quickly cooling down before bedtime and then turning it off does not work.

I find that exciting .... I would also like to have air conditioning. But having the device above the door like in the hotel would not work because it is set too far inside ... and hanging next to/above the bed is also not nice .... That's why your suggestion makes me very curious ... So hanging it in the hallway?

That you don’t have one yet with your nickname surprises me a bit! ;-)

So: It always depends a little on expectations. If you absolutely cannot sleep when it is above 18° in the bedroom, then of course this is not for you. The "one device in the hallway/living room" method is more for people who are satisfied with making the apartment/floor "more comfortable." To dampen the extreme peaks, basically.

Why it works: The most important thing such an air conditioner does in our regions is dehumidifying. And that works quite well across an entire floor. You don’t sleep so well at 27° with 70% humidity. 27° with 45% is a completely different ballgame. And if the AC now also manages to turn 27° into 25°, then at least for me the night is saved.

And that is exactly what a single device (especially in new buildings) can do very well.

There are factors to improve effectiveness: If you have a very high point, such as a staircase that is open up to the roof, you of course hang the indoor unit there. All the warm air wants to go there, gets cooled, falls down again and spreads out. But if the device blows directly towards the stairs, all that air disappears into the ground floor and the bedrooms in the upper floor don’t get any of it. So you do have to put some thought into where you hang the one device. And there are certainly cases where it just doesn’t work so well because of the room layout...

I’ve mentioned it before, but I always like to say it again: The described setup relies on not letting it get too warm in the first place. You must not be afraid to actually run the device. If the indoor thermometer rises above 24 degrees, turn it on, turn it off again in the evening. If it’s still 20 degrees outside at night, run it 24 hours. That sounds wild, but in the end it doesn't really cost much. I have 140 sqm of old building (one floor), which I cool like this even in heat record years with 500 kWh of electricity. My parents in a new building, 135 sqm, need 300 kWh.

I find that exciting …. I would also like to have an air conditioner. But having the device like in the hotel above the door would not work since it is too far inside … and hanging next to / above the bed is also not nice …. That is why your suggestion makes me very curious … So hang it in the hallway?

Just a quick info, these devices are called inverter ducted units, they are huge in size. We had an offer for a Toshiba inverter ducted unit, device dimensions: width / depth / height 700 / 750 / 275 mm for our bedroom. Costs over 5,000 EUR each plus small parts and installation. It was too bulky for us, especially since you also always have to provide an access shaft for maintenance.

Yeah, or you use a regular split...