ᐅ Air-to-air heat pump air conditioning? Comfort factor?

Hello,

Someone recently mentioned air-to-air heat pumps to me, and it sounded interesting. What are your opinions on them? Does anyone here happen to have one already? Unfortunately, I don’t know anyone in my circle who does. How does the heat actually "feel"?

It would also be interesting to know how they perform for cooling. Can you really achieve a significant difference from the outside temperature during the peak of summer?

Thanks very much for your feedback (preferably from those who already have one installed).

I have installed 2 x 3.5 kW split air conditioning units at central points in my house (120 m2 [1300 sq ft], well-insulated older building). I use them both in summer for cooling and in winter for heating. Both functions work very well. In summer, I maintain 22°C (72°F) even in dehumidification mode (very quiet and almost no air movement). However, all windows have external shading.

Heating with these units also works wonderfully. During winter (October to April), I typically run the systems for 3 to 10 hours per day (due to photovoltaic energy). On very cold days, I also use my small 4.5 kW wood stove. At night, everything is turned off. Morning room temperatures are usually around 20–21°C (68–70°F).

If you don’t mind the light humming/whispering sound and the gentle airflow (which is warm in winter), it’s very comfortable to live with. My wife is also satisfied. The only important point is that, in my case, all doors must remain open.

Energy costs are minimal. Thanks to the photovoltaic system and good insulation, last year I only needed to buy about 1200 kWh of electricity and around 1.5 m3 (53 cubic ft) of firewood. Unfortunately, hot water is still supplied by gas, which accounts for about 3000 kWh annually.

We have had similar experiences, and installing the air conditioning system was by far our best decision. In summer, there is an abundance of electricity generated from the roof, so the house is effectively cooled "for free"—we wouldn’t do it any other way!

We use the heating function (we have a Daikin split system installed) only selectively, depending on whether we use our fireplace or not. We also have an infrared heating system in the house, but it is rarely used—only occasionally and in specific rooms when needed.

The only “challenge” for us is that the warm air doesn’t circulate well downwards in our high gallery space. This type of heating is sometimes dismissed as a “hairdryer,” but we don’t see it that way at all; we especially appreciate the quick and flexible way it heats the space.

Like everything, it needs to be well planned, and maybe you have the chance to explore it more closely as winter approaches. We would choose to install an air conditioning system again at any time, and in that sense, you effectively have heating in the house, which this heating option naturally provides.

Please first differentiate here between split air conditioning systems and true air-to-air heat pumps.

And where is it supposed to be installed—in a new building or an existing building?

Ah, okay, I didn’t know until now that there was a difference.
For a new build.

When building a new house, installing a heating system this way is one of the most cost-effective options. However, in various forums, homeowners report that despite careful planning, their electricity costs increase significantly.

Especially depending on the region, for comparable houses, costs can be about twice as high.

At the latest, when winter hits the Swabian Jura and the auxiliary heaters turn on, the expenses really add up.

And the myth that a heat pump can be powered by solar panels in winter is wishful thinking—something that might only work in the Rhine Valley.

Therefore, for new builds, it is recommended to choose an air-to-water heat pump. With proper planning, this means maximizing the supply temperature and keeping pipe spacing under 10cm (4 inches). Please do not include an additional heater in the calculation. Most importantly, avoid adding safety margins, as this often results in an oversized heat pump for the house.