Prefabricated house: Affordable heating system with tiled stove? Ventilation heating?

Hello energy experts,

We would like to build (have built) a prefabricated house in Rhineland-Palatinate next year.

Currently, we are leaning towards an ELK Magic 159. It largely already meets the requirements of our development plan and also meets the KfW40 standard.

However, we are still unsure about the choice of heating system.

The standard is a hot water central heating system with a gas condensing boiler. But since gas is not directly available to us (only via a tank on the property), we are looking for an alternative:

- Pellet heating: The ELK consultant advised us against pellets. Allegedly, the price of pellets has tripled, so such a system is no longer economical.

- Ventilation heating with cooling function and domestic hot water heat pump: This was promoted to us as particularly comfortable, but it is by far the most expensive solution.

- Heat pump with ground probe: Not an option in our area due to the hard volcanic rock.

- Air-to-water heat pump system with underfloor heating: This was promoted to us as a cheaper alternative to ventilation heating.

Since we will be living in a rural area where firewood is relatively inexpensive to obtain, we definitely want to install a tile stove/fireplace. Therefore, it may not make sense to also rely on an expensive heating system.
Our goal is to find an economical system for our house.

What are your opinions on this topic?
What would you recommend?
What have you had good/bad experiences with?

Hello gorgesd,

An air-to-water heat pump installed outside makes sense in my opinion, possibly geothermal energy with ground collectors if the property is large enough. In terms of initial investment, the liquid gas tank will be the cheapest; it can also be invisibly installed underground.

So it is important to compare the acquisition costs with the monthly operating costs and find the most cost-effective solution for you.

A fireplace definitely makes sense, it is cozy and helps minimize heating peaks during severe winter.

Offering KfW40 (now Energy Efficiency House 55) standard with a gas heating system sounds interesting to me. What is the U-value of the exterior wall, or what else is included in the standard construction service description in terms of technology to achieve this value? You should ask to see an energy certificate where this claimed standard actually achieves this value.

Just a thought ...
Oil is easier to store, there are also condensing boilers available, and some systems can even be converted to biofuel by simply changing the nozzle.

Air-to-water heat pump systems can occasionally be problematic at very low temperatures,
then you are practically heating with electricity.
Very well dimensioned systems are by no means cheap to purchase, and the combination with solar collectors on the roof is also interesting.

At the moment, there is again a wave of scammers trying to sell people completely useless
heat exchanger systems at a "great" price.
So be careful!

Why choose a standard with high additional costs?
KfW40 has not been subsidized for a long time.

Why not a DV heat pump with an annual performance factor of over 5.5?
Additionally, there is a BAFA subsidy here.

The information in the performance description does not seem very balanced for the builder.

I just don't understand their performance description; what insulation and U-values do the components in the basic price package have?
Is all of that added as an extra cost?

similar topic as with me. I would advise against ventilation heating -> have you ever thought about cleaning the ducts??? if you use a fireplace, then consider heat recovery (exhaust gas). cross heat exchanger in the chimney, but it should not be made of stone, buffer storage and then onto the underfloor heating. generally, I would recommend low-temperature systems, that will be the standard of the future, I think.

Firewood relatively cheap

that is by no means the case, I live on the edge of the Westerwald in RLP and the prices have risen significantly.

Economically, it is definitely good to insulate.