2 offers for air heat pump

Hello, I hope someone can help me a bit!!! We are having a construction done through a construction company and have now obtained 2 offers from 2 construction companies. These differ mainly in the air heat pump: either 1. a Waterkotte heating/hot water system with energy-saving controller TYPE Ai1 QL 5008.5 or 2. solar-supported air-water heat pump from Rotex Eco Hybrid HPSU Which one is better? Are both recommendable? Both have underfloor heating. I am grateful for any answer, as I have no idea at all!!! :o

I would advise against a company that only has one location in Germany (South), because of spare parts, etc. With our house construction company (and many others) a Rotex was also supposed to be installed, since my brother is a heating/plumbing installer, we had the heating/plumbing costs calculated out and had him do it. When he heard the name Rotex, he threw his hands up in horror, just like the wholesaler. Also because of the workmanship, etc. The company that advertises with the rabbit is also not very recommendable, but is gladly used by house construction companies because it is cheap.

It’s best to ask independent installers what they think......

...Best to ask independent installers what they think......

Which installer is an independent consultant? ;)

I mean to obtain different opinions from experts :p

My answer is a bit off-topic, but please read the article on Wikipedia about heat pumps.

Quote from Wikipedia article on heat pump: "When the evaporation temperature falls below 0 °C, ice forms on the heat exchanger surfaces, creating an insulating layer that significantly deteriorates heat transfer. Therefore, a heat pump that extracts heat from the outside air can only be used effectively at a few degrees above the of water."

Quote RWE Construction Manual, Chapter 16/8: "The smaller the temperature difference between the heat source (environment) and the heat utilization system (heating system), the higher (better) the coefficient of performance."

=> i.e.: the higher the temperature of the heat source, the more efficient the heat pump. Geothermal energy, for example, has a constant temperature of 10°C.

Please keep that in mind. Air-source pumps are certainly the cheapest type of heat pump, but when it really gets cold, these units no longer work.

So my advice: invest more and get a heat pump with, for example, geothermal energy. Or: invest less and get a gas condensing boiler. Keep in mind: if your house is very well insulated, you will heat very little anyway – which also relativizes the cost of gas.

Don’t just follow the hype. Just my 2 cents.

Hello,
I am sure our experts will still speak up, but:

Quote Wikipedia article about heat pumpsn: "When the evaporation temperature falls below 0 °C, ice forms on the heat exchanger surfaces, creating an insulating layer that significantly impairs heat transfer. Therefore, a heat pump that extracts heat from the outside air can only be used effectively a few degrees above the of water."

Wikipedia® is not a verified source; anyone can write whatever they like, and in most cases, the statements made there do not withstand verification.

Please keep that in mind. LW pumps are certainly the cheapest type of heat pump, but when it really gets cold, these devices no longer work.

That is – with all due respect – nonsense. It is certainly debatable whether the use of an air-to-water heat pump makes sense or not; denying its function for sure does not belong to it.

So my tip: invest more and get a heat pump with, for example, geothermal energy. Or: invest less and get a gas condensing boiler. Consider: if your house is very well insulated, you heat very little anyway – which also relativizes the cost of gas.

The decision for a geothermal heat pump always depends decisively on soil conditions and the associated costs – and – by the way – the values suggested by manufacturers are rarely achieved. The decision for an air-to-water heat pump, on the other hand, is made for pragmatic cost reasons. Both decisions, in turn, reflect the move away from fossil fuels.

Despite all the discussion and your advocacy for gas condensing boilers, every builder should consider that all the aforementioned systems have pros and cons. Therefore: if the builder is not sure, he should stick to gas combined with underfloor heating and calmly wait for developments in the renewable energy market. That way it will work out ;)

Best regards