ᐅ Which heating system? Where to start? With the manufacturer?

Hello everyone,

We are currently trying to gather information about heating systems but are a bit stuck. We plan to install an air-to-water heat pump for a KF55 house with 200m² (2150 sq ft) of living space and a volume of just over 900m³ (31,800 cu ft) across 2.5 floors. According to KFW, calculations are based on 275m² (2960 sq ft) of living space due to our high ceilings. I’m still getting answers on the required capacity and whether it should be a split system, but when it comes to deciding on the specific heating brand or model... we have no clue.

When we talk to installers, each one swears by the brand they install. Whether the equipment is actually good or if they just earn the highest margin on it, I can’t tell. Online, I often find answers saying that heating and controlled mechanical ventilation depend on the specific requirements, but surely the differences can’t be that big...

I compare it to cars. There are premium manufacturers like BMW, Mercedes, Audi, etc. Then there are luxury cars such as Lamborghini, Ferrari, Bentley, and very affordable brands like Dacia. And then you have brands focused on value for money, like Skoda and Seat. Skoda (VW) and Seat (Audi) might not have the newest gadgets but are close in quality to premium classes, while being significantly cheaper.

Is there a similar classification for heating and controlled mechanical ventilation systems? Or I strongly assume there is, but how can I categorize the manufacturers? Viessmann, Nibe, Vaillant, Buderus... these are companies I know but can’t really place. When reading, I come across names I’ve never heard before, but that doesn’t mean they are bad. For example, Weishaupt?

We are more looking for something like a BMW or a Seat, depending on price. Can you help us here? Is there maybe a list or are we missing something?

Of course, installation also matters, because even the best heating system won’t help us if it’s poorly installed. Or are manufacturer differences negligible so that we should focus more on the installer and just choose whatever brand they recommend?

Cheers

Let me give you an example. Our neighbor has a Junkers system installed by company W. My son-in-law also has a Junkers system, installed by company H. The systems are identical. W installs dozens of them each year; their technicians are trained and know Junkers very well. H installs them rarely and mostly works with Viessmann systems. His team is not familiar with Junkers. The result: W adjusted the system well in the neighbor’s house during autumn, keeping the house warm with moderate electricity consumption. H, on the other hand, couldn’t get it right—the system always used a lot of electricity for heating. Eventually, the factory service technician came, made the necessary adjustments, and now it runs efficiently. What does this teach us? Is Junkers good or bad? Or does it depend on the installer? Karsten

Nordlys schrieb:
What does this teach us? Is Junkers good or bad?

Bad, since it seems difficult to set up properly ;-)

Just kidding. I understand what you mean. But I could simply look for the company that installs the manufacturer I prefer. Of course, if, for example, Nibe were my favorite and the installer in our area had a bad reputation, I would choose an alternative. However, if the best installer does not work with good models, then I wouldn’t go with them either.

Controlled residential ventilation: definitely separate from the heating system. Include humidity recovery and preferably size it slightly oversized rather than undersized. The manufacturer is relatively unimportant. The installer should be experienced and take the planning seriously.

Air-to-water heat pump:
1. Design the surface heating system for the lowest possible supply temperature, based on room-specific heating loads determined early according to DIN standards, considering your desired temperatures. In bathrooms, consider adding wall heating alongside underfloor heating if you want the room noticeably warmer than the rest of the house (otherwise, electric heating can be added for occasional extra heating).
2. Only after the total heating load of the house is known should you look for the air-to-water heat pump. It should not be oversized (do not add any buffer to the heating load; it won’t get too cold inside!) and must be modulating.

When it comes to the air-to-water heat pump, it’s best if you educate yourself thoroughly. Don’t rely solely on craftsmen, architects, or anyone else—it often goes wrong. The hydraulics are at least as important as the heat pump itself (no buffer tank or hydraulic short circuits via valves) for the heat pump to run efficiently. If you have some risk tolerance and commitment, take a look at the compact units from Panasonic, especially the 5kW model: efficiency is good, price-performance ratio is excellent. 5kW is feasible for this house size if the insulation is adequate. However, no one installs it with a full warranty, and convincing craftsmen is the challenge. On the plus side, a local contractor can install it following proper guidelines because it’s not a split system.

There is a list of heat pumps and their efficiency available somewhere through BAFA for funding purposes. Try searching for "heat pump database," which might also be helpful.

5 kW output? That seems very low to me.

Unfortunately, I can only report negative experiences with my air-to-water heat pump from Viessmann. Countless malfunctions and no solution in sight. Viessmann appears unorganized and unprofessional.

Vitocal 200s