ᐅ Is a multi-split air conditioning system suitable for heating?

SaniererNRW123 schrieb:

There is a reason why this type of heat pump system never became popular (putting aside the poorer performance in winter).

Yes, air source heat pumps do have lower efficiency in winter. However, it doesn’t matter how the heat is distributed inside the house, as long as you don’t have to heat radiators to 50°C (122°F)…

Nutshell schrieb:

That’s right, the main goal is always to warm the indoor air so that living beings feel comfortable.
Air is— as you pointed out, except for infrared—what is ultimately heated.

An air conditioner is often perceived as unpleasant because of the “draft.” Underfloor heating is considered comfortable due to its good heat distribution without hotspots.
Radiators and stoves only warm one corner because the air is not circulated.

You’re quite clever 🙂

Hi, please don’t take this the wrong way, but I’ve been active in forums for some time discussing this question. Unfortunately, only about 10% of the answers are reasonable; the rest are ignorance, prejudices, silly comments, and sarcasm—very helpful when you ask a serious question.
The remark "You’re quite clever" can only serve as provocation. Why do people do that? Is it necessary? Does it make them feel better?

I accept the point about drafts, but I don’t see why air-to-air heat pumps would be less effective. Basically, the outdoor units are the same; only the indoor unit either heats air directly or heats water (which then heats the air through radiators). From my gut feeling, the first method should be more efficient because you don’t first have to heat water to around 40°C (104°F) to warm the air—you warm the air directly. But usually, reality is different.
There are now very quiet units with intelligent controls that can detect when people are nearby and adjust the airflow accordingly (at least that’s what I’ve read).

The claim that many outdoor units would be required and need maintenance is not entirely true. I would only need two units. One air conditioner is already installed on the roof and will remain there anyway. A multi-split system would be sufficient for all other rooms. This would be similar to an air-to-water-to-air heat pump. The advantage for me would be that I can position the air conditioning unit better than the unit for the basement.

gagagu75 schrieb:

I accept the issue with drafts, but I don’t understand why it would be less effective compared to an air-to-water heat pump.

Maybe we should simply list the advantages and disadvantages of using an air conditioner (high-quality split system) as a heating source compared to a heat pump/radiant floor heating:

Pros:
- High efficiency
- Can cool in summer
- Cost
- Ideal for smaller rooms
- Fast response time

Cons:
- Not designed for very low winter temperatures
- Due to the technology and typical indoor unit placement, increased drafts (the system needs to blow more to move warm air from the ceiling to the floor)
- Noise level (not loud, but still louder compared to traditional radiant floor heating)
- No domestic hot water production, so additional costs apply
- One indoor unit usually isn’t sufficient for larger rooms
- Different type of warmth than radiant floor heating (always cold floors and drafts, see above) – radiant floor heating is generally perceived as much more comfortable
- Higher heating temperature required (unlike radiant floor heating where the screed acts as a buffer/storage)

I can’t say how well an air conditioner automatically adjusts its operation based on outdoor temperature, as I lack experience with this.

SaniererNRW123 schrieb:

Perhaps we should simply list the disadvantages and advantages of using an air conditioner (high-quality split system) for heating compared to a heat pump/floor heating:

Cons
- Not designed for very low winter temperatures
- Different type of heat compared to underfloor heating (always cold floors and draft, see above) – underfloor heating is generally perceived as much more comfortable
- Requires higher heating temperatures (unlike underfloor heating, where the screed acts as a buffer/storage)

As far as I know, there are also air conditioners that can handle -15°C (5°F) or even -20°C (-4°F). I believe it’s the same with air-to-water heat pumps (please correct me if I’m wrong). Of course, underfloor heating is always better because of the larger surface area, but unfortunately that’s not an option for me.

Okay, that helps me. I will now compare the options. Fortunately, I still have a working heating system. When it gets cold, I will try lowering the flow temperature to 40°C (104°F) and see if the house warms up. Since I have an air conditioner in the attic, I will temporarily disconnect the heating there and test heating with the air conditioner instead. Hopefully, I will also receive the offers for the air-to-water heat pump and the photovoltaic systems soon, then I will decide how to proceed.

gagagu75 schrieb:


The remark "You are really clever" can only be meant as provocation. Why would someone do that? Is it necessary? Does it make you feel better?

Your response is great, but the assumption that this was meant as provocation is a misunderstanding. I really wanted to express that he is clever, so it was a compliment.

I’m curious to see how the heating will perform in our single-family house with the split air conditioning system. It didn’t bother me in the office.

At -15 degrees Celsius (5°F) I will turn on the gas heating 🙂 because the split air conditioner is only designed to operate between -15 degrees Celsius (5°F) and +46 degrees Celsius (115°F).

Nutshell schrieb:

Your response is great, but the assumption that this was meant as a provocation is a misunderstanding. I really intended to express that he is clever, so it was a compliment.

Thanks for the compliment then.

I will no longer have a gas heating system, so if anything, the heat pump will have to work even at low temperatures. I’m considering a stove for this scenario, but my household government is still a bit hesitant :-)