ᐅ Air source heat pump with fireplace, hydronic stove, domestic hot water heating

Behaim schrieb:
What data do you need for the calculation?

Basically the same initial data as required for the energy saving regulation/KfW verification. Additionally, among other things, the heating load.

Behaim schrieb:
... I only know that our contractor is also authorized to issue energy performance certificates. Does that mean they are a certified energy consultant?

You can generally assume that.

Behaim schrieb:
... He assured me that the system will be precisely calculated and sized if we decide on air or ground source heat.

Then everything should be correct. Make sure to get these calculations in writing and, if possible, have an MEP engineer review them.

Behaim schrieb:
... Our construction company is from the local area and works only regionally, so also with local specialist firms. I trust them more than a general contractor operating nationwide in Germany anyway.

That is a good approach, as nationwide providers often cause more problems.

Best regards.

We are currently gathering information for the construction of a single-family house of about 120 square meters (1290 square feet) and want to prepare ourselves with some details in advance to be better equipped for discussions with contractors.

A fundamental question: Is the electric heating element in the air source heat pump only there to provide additional heat when outdoor temperatures are very low and the heat pump alone cannot generate enough heat, or is it also installed to protect the outdoor unit from frost damage?
In any case, we plan to install underfloor heating alongside the main heating system (regardless of its type) and also include a wood stove or heating stove.
If the stove is not strictly needed to protect the system, could it replace the heat pump’s electric heating element for covering cold temperature peaks? Would it then be possible to size the air source heat pump smaller?

I am only looking for a general answer to better understand the system at this stage—not a detailed heating calculation.

Regards, Jasper

Oh, one more question:
What are the typical annual maintenance costs and possible wear-and-tear part expenses for a fiber optic cable?

Regards, Jasper

Jasper schrieb:
...A fundamental question: Is this electric heating element in the air source heat pump only there to provide backup heating when the outdoor temperature is very low and the air source heat pump can no longer generate enough heat, or is it also installed to protect the outdoor unit from frost damage?

The first is correct. The outdoor unit must first be clearly defined. This can be either the evaporator (in split systems) or the entire air source heat pump.
Air source heat pumps are among the most sensitive heat generators, as can be seen here, for example.

Precise planning and sizing of the entire system is particularly important in this context. Significant mistakes have been made and continue to be made here, which have unfairly damaged the reputation of air source heat pumps and created fear around the "evil heating element."
In well-designed systems, the heating element accounts for less than 1% of the annual heating demand—a minor "cost" factor within the overall energy balance.
However, in poorly or incorrectly designed systems combined with possibly wrong equipment selection, this can quickly turn into a costly problem with excessive energy consumption.

Jasper schrieb:
...Couldn’t it—if it is not absolutely necessary for system protection—replace the heating cartridge of the air source heat pump and absorb the cold peaks instead?

"Instead of" (physically) is probably not very practical! However, every kilowatt-hour actually delivered by the wood stove really contributes to improving the energy balance, especially when it occurs during particularly low outdoor temperatures. The annual performance factor of the air source heat pump improves.
But the expected effects must be assessed beforehand. For example, is the wood fuel for the stove free, or does it need to be purchased?
The primary energy factor is generally quite poor in this scenario! With planned controlled ventilation with heat recovery, the overall balance can be improved through sensible design.

Jasper schrieb:
...Can the air source heat pump then be sized smaller?

I would strongly advise against this! Moreover, what is the sizing of the air source heat pump based on?
Annual maintenance costs are generally not incurred, although surprisingly, maintenance contracts are often sold here unnecessarily. Exceptions include systems where refrigerant inspections (> 3 kg content) are required.

Best regards

I admit I don’t understand all the technical details, but as a neighbor affected by two air source heat pump owners, these units have become a huge annoyance for me! In May 2012, I moved into my new 1.5-story wooden house, 110 m² (1,184 sq ft) (Baufritz). At first, I considered installing an air source heat pump myself, researched it online, and thankfully decided on a solar-assisted gas condensing boiler instead, along with a Contura (Nibe) fireplace. Our new neighbors started building in May 2012 and, as mentioned, chose air source heat pumps—Rotex models—which have been a noise disaster. Since October, these units have been running almost nonstop, turning what was once a wonderfully quiet Baltic Sea holiday village into an industrial noise zone that causes headaches and makes it impossible to open bedroom windows. These devices are anti-human! They can hardly be economical either. I haven’t even needed to turn up my gas heating; one basket of wood per day is enough to keep the house cozy all day. Meanwhile, the Rotex pumps keep running constantly, even at night (why???), consuming electricity. And please don’t say the noise is imagined... the local environmental protection authority visited and measured a significant peak at 80 hertz (low-frequency infrasound can cause long-term health problems!!) and confirmed that the air source heat pumps are not state-of-the-art technology. Of course, Rotex denies this. And naturally, the units are always placed under the neighbor’s bedroom window—not under their own windows, even though theirs supposedly don’t make noise, haha. I can only advise against installing such noisy, power-hungry devices unless you really hate your neighbors.
Wombel

What’s the fuss, Wobel? There are noise protection regulations (TALärm) and corresponding limit values.
If these are exceeded, don’t waste your time on a minor uproar but focus on preparing the complaint.
However, I have to agree with you that not every neighbor considers the impact on others when choosing a heat pump and its installation location. Sometimes just rotating it slightly is enough. As for the “continuous runner,” it might be that the temperature difference (delta-T) for domestic hot water and/or service water is set too low, causing the unit to turn on too frequently. Also, Rotex models have a “silent mode” – if you talked to your neighbor, it would be easy to check this.