Heating type for new construction - Which is the best?

Yes, I share the skepticism towards heating engineers, also possibly regarding blanket statements made by planners. But as I said, he showed us a concrete offer, which I have here and would like to briefly present for reasons of transparency to show what all is involved. Perhaps this helps someone with their personal assessment:

Location: Franconia, metropolitan area Nuremberg/Erlangen
Offer for a ground probe system for a heat pump with 10.2 KW heating capacity including connection and filling:

[*]Probe trip (preparing, assembling, traveling to the construction site, setting up the drilling location, departure after completion)
1 flat rate 350 EUR
[*]Probe drilling notification (creation of the drilling notification at the local authority, excluding approval fees from the offices and a necessary expert of water management)
1 flat rate 65 EUR
[*]Probe PSW (water management expert, construction supervision, acceptance, final documentation)
1 flat rate 850 EUR
[*]Complete probe (creation of ground probe boreholes with a depth of 50m each, total 3 pieces, withdrawal capacity per meter 50.00 watts, soil classes 2-7, double U-probes, cementing of the annular space, pressure and flow test)
150m at 42 EUR/m -> 6300 EUR
[*]Probe auxiliary piping (installation and pulling of auxiliary piping including drilling out and additional costs for cementing)
12m at 22.25 EUR/m -> 267 EUR
[*]Probe connection (connecting the ground probes with supply and return flow, max distance 12m, connection according to Tichelmann, hydraulically balanced)
3 pieces at 235 EUR -> 705 EUR
[*]Probe digging (soil class 2-5 with mini excavator 3 tons, excavation up to max depth 1.25m. Laying of pipes, sand filling, backfilling and compacting trenches, making the rough planum, material remains on site)
18m at 25 EUR/m -> 450 EUR
[*]Probe core drilling (for house entry for supply and return flow DN100)
40cm at 2.10 EUR/cm -> 84 EUR
[*]Probe Doyma (masonry feed-through sealing)
2 pieces at 75 EUR -> 150 EUR
[*]Probe antifreeze (delivery and installation of heat transfer fluid Terra Calidus N" 350l
350l at 2 EUR/l -> 700 EUR
[*]Probe container (providing and holding drilling spoil container, disposal of uncontaminated material)
1 flat rate 245 EUR
[*]Probe wastewater (disposal of drilled water via discharge into the local sewer, approval fees, discharge fees, and incidental work)
1 flat rate 15 EUR

Total including VAT 12,317 EUR – as said from 2012, so 5 years ago. Assuming a price increase of 2% per year results in about 14,000 EUR in 2017/18.

Minus effective 3,000 EUR BAFA subsidy (5,000 EUR for ground probe minus 2,000 EUR for air-water heat pump BAFA subsidy) leaves about 10,000 EUR additional cost compared to air-water heat pump. With assumed savings of 250 EUR/year on electricity compared to air-water heat pump, it would amortize after 40 years (!), with 500 EUR/year after 20 years. I would assume equal longevity of the probe and the air-water heat pump... that really makes you think about why one should choose a ground probe....

Yes, at that price it doesn't make sense. Especially since the improved sealing material is not apparent, it may possibly be an additional cost. However, the probe should last 50 years or longer. But that does not make the calculation significantly better.

I would take a look at a trench collector in this specific case, which can be done well as a DIY project. It's outrageous what is being charged here. And definitely have the room-specific heating load calculation done. After that, the heating engineer has to plan the underfloor heating.

In this specific case, I would take a look at a trench collector, which you can easily do yourself. It's outrageous what prices are being asked here.

Unfortunately, a trench collector doesn't work on our property, I've already thought about that [emoji17] It will probably come down to an Ochsner... if it fits the heating load calculation. You can't have everything [emoji6]

The offer above also matches our current offers for new construction. We therefore tend towards gas plus solar. In principle, I find the topic of solar houses interesting, but we have almost entirely glazed towards the south and I hope, with good insulation and the solar gains, to hardly need any heating anymore.

Gas fuel cell is currently subsidized with 11k euros, recently promoted by Viessmann at a trade fair. However, it’s only really great if you are constantly consuming, especially in summer the system only runs for hot water; for me it’s more interesting on paper but in real life only half...

I find the topic really difficult and currently it is delaying the energy certificate for our building permit because we haven’t decided yet.

Guys, depending on the living area and insulation standard, in the new building you have between 5 and 8 kW heating load at your design temperature (-12 to -16 degrees). And you only have these temperatures for a maximum of 3-4 days a year. If a heating engineer comes along and says the heat pump is then constantly running at full load, he has not understood the subject. Additionally, internal and solar gains are not considered in the heating load calculation.

What is needed here is a good, accurate planning of the underfloor heating, then you can also heat super efficiently with an air-water heat pump at 30 degrees flow temperature. And it only costs a little more planning.

These oversized heat pumps are then installed with buffer tanks, which completely destroy your efficiency. Unfortunately, this is common but wrong. Please inform yourselves extensively here and annoy the heating engineer, otherwise it’ll be like this again: my heat pump is broken after 3 years or consumes an immense amount of electricity.