Which heating? Where to start? At the manufacturer?

Hello everyone,

we are currently trying to get information about the heating system and somehow can’t make any progress. It is supposed to be an air-to-water heat pump for a KF55 house with 200m² of living space and just over 900m³ volume across 2.5 floors. According to KFW, they calculate with 275m² of living space because we have high ceilings. I am still getting answers about the necessary capacity, whether it should be a split system, etc., but what specific heating system it should be... we have no clue.

When we talk to installers, everyone swears by the brand they install. Whether the device is really good or if they just have the biggest margin there, I cannot assess. On the internet, I often find answers that the heating system and controlled residential ventilation depend on the requirements, but it can’t differ that much...

I compare it to cars. There are, for example, premium manufacturers like BMW, Mercedes, Audi, etc. Then there are luxury cars like Lamborghini, Ferrari, Bentley, etc., very cheap manufacturers like Dacia, and then let's say value-for-money manufacturers like Skoda and Seat. Skoda (VW) and Seat (Audi) may not have the newest gadgets, but in terms of quality, they are very close to the premium classes. For a significantly lower price.

Is there such a categorization also for heating and controlled residential ventilation? Or at least I assume so, but how can I classify the manufacturers? Viessmann, Nibe, Vaillant, Buderus … these are companies I know, for example, but I cannot place them. While reading, I encounter names I have never heard of before, but that doesn’t mean they are bad. For example, Weishaupt?

We are rather looking for a BMW or Seat, depending on the price. Can you help us here? Is there maybe a list or are we doing something wrong?

Of course, installation also matters, because if we have a good heating system that is poorly installed, it doesn’t help us. Or are the manufacturers basically all the same and we should pay more attention to the company and take what they install?

cheers

I'll give you an example. Our neighbor has a Junkers. Installed by company W. My son-in-law has a Junkers, installed by company H. The systems are identical. W. installs dozens of them a year, his people are trained and know the Junkers exactly. H. installs them rarely, he is actually a Viessmann installer. His guys don’t know the J. Result: W. adjusted it well in autumn at the neighbor’s, house warm with moderate electricity consumption. H., on the other hand, couldn’t get it under control, it always heated with a lot of electricity, now the factory service came, adjusted it, and it finally runs efficiently. What does this teach us? Is Junkers good or bad? Or does it depend on the installer? Karsten

What does this teach us? Is Junkers good or bad?

Bad, since it seems difficult to adjust ;-)
No, just kidding. I understand what you mean. But I could just look for the company that installs the manufacturer I prefer. Sure, if, for example, Nibe was my favorite and the installer in our area has a bad reputation, then I would go for an alternative. But if the best installer doesn’t install good models, then I won’t go for it either.

Controlled residential ventilation: absolutely separate from the heating. With humidity recovery and better over- than undersized. Manufacturer relatively irrelevant. The installer should have experience and take the planning seriously.

Air-to-water heat pump:
1. Plan surface heating at the lowest possible flow temperature, for which determine the room-specific heat load according to DIN early on with your desired temperatures. In the bathroom, possibly plan wall heating in addition to underfloor heating if it should be significantly warmer there than in the rest of the house (otherwise electric heating additionally for occasional boost heating).
2. Only when the total heating load of the house is known, look for the air-to-water heat pump. It should not be oversized (so do not add any buffer to the heating load, it will not get too cold in the house!) and should be modulating.

For the air-to-water heat pump, you are unfortunately best advised to delve deeper into the subject yourself. Do not rely on the craftsmen, architects, or anyone else – it regularly goes wrong. The hydraulics are at least as important as the heat pump itself (no buffer tank or shortcuts via valves), so that the heat pump runs efficiently. If you have a bit of personal risk willingness and commitment, then take a look at the compact units from Panasonic, especially with 5kW: efficiency is good, P&L is outstanding. 5kW for the house size is feasible, insulation must fit. But no one installs it under full warranty or it is then a challenge to persuade craftsmen. On the other hand, the craftsman next door can install it according to suitable specifications because it is not a split unit.

At Bafa, there is a list somewhere for funding purposes with heat pumps and their efficiency. Google "Wärmepumpendatenbank," that might also help.

5 kW output? That seems very low to me.

Unfortunately, I can only report negative things about my Viessmann air-water heat pump. Countless malfunctions and no solution in sight. Viessmann is clueless and brazen.

Vitocal 200s