Air heat pump with fireplace, water-bearing stove, hot water heating

Which data do you need for the calculation?

Essentially the same initial data as for the Energy Saving Ordinance/KfW verification. Additionally, among other things, heating load.

.... I only know that our contractor is also allowed to issue energy certificates, so is he then a certified energy consultant of this kind?

You should be able to assume that.

.... He assured me that the system, if we decide on air or geothermal energy, will be calculated and dimensioned very precisely.

Then everything should be fine. Have these calculations given to you in writing and, if necessary, have a TGA planner review them.

.... Our construction company is from the neighborhood and only operates regionally, so also with regional specialist companies, I have a bit more trust in that than in a nationwide general contractor

That is a good approach, as the supra-regional ones often cause more problems.

best regards

We are currently gathering information about building a approx. 120 sqm single-family house and want to prepare ourselves with some information in order to be better prepared for the discussions with builders.

A basic question: Is this electric heating rod of the LWL only there to assist when the air heat pump can no longer produce enough heat at particularly low outside air temperatures, or is it also installed to protect the outdoor unit from frost damage?
In any case, besides the heating (whatever type it may be) with underfloor heating, we will also install a wood stove or heating stove.
That could—if it is not absolutely necessary for the protection of the system—instead of the heating cartridge of the LWL, absorb the cold peaks. Can the air heat pump then be designed smaller?

I am only looking for a basic answer now to better understand the system. And of course, not for a heating calculation.

Regards Jasper

oh yes, one more question: What are the annual maintenance costs and, if applicable, wear and tear parts costs for a fiber optic cable? Regards Jasper

...A fundamental question: Is this electric heating rod in the air heat pump only there to assist when the air heat pump can no longer produce enough heat at particularly low outdoor temperatures, or is it also installed to protect the outdoor unit from frost damage?

The former is correct. The outdoor unit would first have to be defined. This can only be the evaporator (split systems) or the entire air heat pump. Air heat pumps are the most sensitive heat generators, as can be seen here, for example.

Precise planning/dimensioning of the complete system is particularly important here. Significant mistakes have been made and are still being made, which have unjustly discredited the air heat pump and created a fear of the "evil heating rod". In well-planned systems, the proportion of the heating rod is barely < 1% of the annual heating workload! So a minor "cost" problem within the overall energy balance. In poorly or incorrectly planned systems combined with possibly wrong device selection, however, this can quickly become a money pit with excessive consumption costs.

...Couldn’t it—if it is not absolutely necessary for the protection of the system—catch the cold peaks instead of the heating cartridge of the air heat pump?

"Instead of" (physically) will probably make little sense! However, every kWh that is actually contributed by the wood stove improves the energy balance, especially when it occurs at particularly low outdoor temperatures. The annual performance factor of the air heat pump improves. However, the expected effects must be assessed beforehand. For example: Is the wood for the stove "free" or does the fuel have to be purchased? The JNG is fundamentally thought to be poor here! With a planned controlled residential ventilation with heat recovery, the overall balance can be improved by a sensible design of this.

...Can the air heat pump then be designed smaller?

I would strongly advise against this! Moreover, according to what criteria is the air heat pump designed? Annual maintenance costs essentially do not arise, although, in my opinion, totally nonsensical, maintenance contracts are also often sold here. Exceptions are systems where a refrigerant inspection (> 3 kg content) is required.

Best regards.

I admittedly have no idea about all this technical stuff, but as an affected neighbor of two air source heat pump operators, these things have become a huge thorn in my side! I moved into my new 1.5-story wooden house, 110 m2 (Baufritz), in May 2012. At first, I also considered maybe installing an air source heat pump, did some Googling, and then thankfully decided on a solar-supported gas condensing boiler, and also put in a Contura (Nibe) stove. Our new neighbors then started building in May 2012 and, as mentioned, rely on air source heat pumps... Fa Rotex — a noise disaster; since October these things have been running almost continuously, spreading industrial noise in this formerly wonderfully quiet Baltic Sea holiday village, causing headaches and making it impossible to open the bedroom windows. These things are inhuman! And they can’t really be economical. I didn’t even have to turn up my gas heating; a basket of wood per day is enough to keep the house comfortably warm all day long. Meanwhile, Rotex keeps rattling nonstop... even at night... (Why???), and consumes electricity. And please don’t say the noise is imagined... the local emissions control authority was here and measured a clear peak at 80 Hertz (low-frequency infrasound makes you sick over time!!) and pointed out that the air source heat pumps are not state of the art. Rotex naturally denies this. And of course also of course, that these things are planted by the neighbor under the bedroom window... never under their own, even though they supposedly make no noise, haha. I can only advise against installing such a noise-producing power hog, unless you hate your neighbors. Wombel

What's the fuss, Wobel? There is the TALärm and corresponding limit values. If these are exceeded, don't waste your time on such a dwarf uprising, but on the complaint. But I have to agree with you that not every neighbor thinks of his neighbors when choosing the heat pump and its location. Sometimes just a rotation is needed. As for the "marathon runner," the delta-T of the drinking and/or utility water is probably set too low and the unit switches on too often. Rotex also has a "whisper mode" – if you stood in dialogue with your neighbor, it would be easy to verify this once.