Extremely dry air due to ventilation heating - what can we do?

Apart from the topic, I don't think it's very smart to post email addresses in a public forum now...

What is wrong with the contact details being freely available, for example on the homepage, and the gentleman being asked if it is OK for him?

To what extent is this heating technology "controversial"? The first systems have already been in operation for several years – are there now any reasonably objective studies/statements about what the actual advantages and disadvantages of the heating systems are? Perhaps the "Bosch project team" could share their knowledge with us? As a potential builder in the planning phase, I find it extremely difficult to find this topic presented anywhere without emotion – and to draw conclusions from it... Are there any good presentations somewhere about the good and/or bad aspects of the various heating systems, especially with ventilation heating? Some "rumors" persist (germs in the pipes, exhaust air being pushed back, temperature not being easy to control, etc.) – but what is really true is hard to find out – or am I overlooking obvious reports/studies? (And what are the alternatives with their pros/cons? – probably there is no "perfect" solution, otherwise everyone would do it that way, ...) Many thanks and best regards, Björn

Hello, I came across the forum because I am currently planning a prefabricated house and the question of the right heating technology is bothering me quite a bit. I have a similar experience in that there are few objective comparisons between the air-to-air heat pump and the air-to-water heat pump. The post is already a bit older. Does anyone have a tip for me now on how to get a bit smarter on this? You read a lot of bad things about the air-to-air heat pump, but often it also turns out that some settings were wrong... Furthermore, I often find numbers in forums (about performance, heat recovery, auxiliary heating) showing that the air-to-air heat pump performs worse than officially stated, but then I can’t find proof for these statements either... I would be grateful for help! For your information, I am planning a KfW40plus house, 180 sqm, fireplace, photovoltaics...)

And the air-to-air heat pump is set and must be? You are traveling in hotels and know the indoor climate? The rooms are often equipped with air-to-air heat pumps in chain houses (Hilton, Marriott, etc.). The air-to-air heat pump is what is commonly called an air conditioning unit with indoor units on the wall or as a duct version integrated into the ventilation of the hotel rooms. The same can also be done in houses.

No, of course it doesn't have to be an air-to-air heat pump. The problem is just that the prefabricated house builders I have been in contact with so far install this technology without an extra charge, and for the air-to-water heat pump with underfloor heating they add 15-20 thousand on top. I am currently very uncertain between the marketing promises of this system (sufficient at 40+, you need a ventilation system anyway, allergy-friendly, cost-effective..) and my own doubts/warnings on the internet (dry air, cold rooms, high electricity consumption, you commit to this technology for a long time). I recently attended a consultation in a show house with an air-to-air heat pump and despite wearing contact lenses I didn’t have dry eyes. Maybe it’s not all so bad after all, or perhaps a few hours were not enough to judge... In gathering information, I just get the feeling that there are pure "supporters" and "rejecters." I have made an appointment with an energy consultant, maybe he can advise me a bit more objectively... And of course I gladly welcome help here from the forum..

Air-to-air heat pumps (air conditioning) are something entirely different from exhaust air heat pumps integrated into ventilation systems. The former can even be used well in old buildings. The only disadvantages are the swirling air and noise. They are quite efficient. Exhaust air heat pumps (the Proxxon comfort cozy stuff) are actually only suitable for passive houses. The energy for hot water must be drawn from the exhaust air of the house. If the house is not sufficiently insulated, it loses more energy than it gains from people and machines, and direct electric heating is needed. There are also hybrids that have an additional heat exchanger outdoors, but these also have the disadvantage that warm air only reaches where intake air vents are located. I recently learned that some systems therefore need additional heating with IR heaters in exhaust air rooms (bathrooms, utility rooms). So nothing but uncomfortable or inefficient. My very personal opinion on the subject is therefore: Either passive house (which is cheaper and significantly more environmentally friendly after only a few years in the full cost calculation) or underfloor heating with air-to-water heat pump (or brine-to-water heat pump in very cold areas).