ᐅ Experiences with gas or air-source heat pumps?

It is certainly not as robust as gas, but there is no need to be afraid.

Why isn’t there a distinction made between air-to-air heat pumps and air-to-water heat pumps?
A colleague of mine has an air-to-air heat pump and consumes over 11,000 kWh of electricity per year. The house was newly built in 2006. That’s quite a lot.
Currently, we have used about 2,300 kWh after roughly 8 months, including a short period of screed drying. We also have a baby, so we’ve kept the whole house consistently above 24°C (75°F) for the past month.
In our region, there is snow—enough that I was still shoveling snow last week.
I wonder what really went wrong there.

tomtom79 schrieb:
Why is there no distinction made between air-to-air heat pumps and air-to-water heat pumps?
A colleague of mine has an air-to-air heat pump and uses over 11,000 kWh of electricity per year. The house was newly built in 2006. That’s quite a lot.
We currently have about 2,300 kWh after around 8 months, including a short period of screed drying. We also have a baby, so the temperature in the whole house has been kept above 24°C (75°F) constantly for the past month.
And in our region, there was so much snow that I was still shoveling it last week.
I wonder what really went wrong there.

These air-to-air heat pumps are basically just electric heaters... They are often pushed onto Bien-Zenker customers and advertised as a miracle heating system. I would bet your colleague’s house is a Bien-Zenker.

Still shoveling snow last week? Do you live on the Swabian Jura?

An air-to-air heat pump in a Passive House/KfW 40 house in the Rhineland region can definitely be a viable concept. Of course, as a builder, you need to ensure that the costs are appropriate.

Yes, in a passive house, that can make sense. But anyone who blindly sells it as a miracle heating system to uninformed customers should actually share in the electricity costs. After all, only very few build KfW40 (+).

Wow, it seems I’ve sparked quite a debate here. In any case, thank you all for the interesting contributions!

In the meantime, I have gathered information from various sources:

1. Consumer advice center, hotline: From their perspective, air source heat pumps are at best so-so and often don’t perform well because they are incorrectly sized and installed. They can become energy guzzlers, especially at very low outdoor temperatures when they can only extract little heat and have to use electricity to supplement. Personally, the advisor would prefer gas. The information brochure also takes a rather critical view of air-to-water heat pumps.

2. County energy advisor: Air-to-water heat pumps are not fundamentally bad. Gas is economically viable, but it needs to be combined with, for example, solar thermal systems to meet the new minimum standards. No one can predict how electricity and gas prices will develop. His personal favorite (not necessarily for us) is a wood pellet heating system, especially if a fireplace is already planned. With some luck, the same chimney can be used since both use wood. Additionally, the chimney sweep would visit twice a year anyway because of the fireplace. Wood pellets (pressed wood waste) are a resource that, at least historically, has not been very expensive.
He estimates the costs at about €15,000 for gas/solar thermal, around €22,000 for air-to-water heat pumps, and €25,000–30,000 for wood pellet systems.

My preliminary conclusion: We will decide on a house plan. It will definitely have large windows facing south/southwest to benefit from natural solar heating in winter. Possibly the roof overhangs will be designed to prevent overheating, at least in the upper sleeping area.

Which system I will discuss further with the energy advisors and suppliers — and in any case, I will have the final offer reviewed again by the consumer advice center or the home builders’ protection association.

Enjoy your holiday evening!