New gas heating system - How to design underfloor heating based on a heat pump?

We are still in the planning phase for our little house.
At first, I was considering going directly for a heat pump, but I have now abandoned this idea for cost reasons.
According to our planner, the difference when building without a heat pump is not only in the different heating technology but also in a "thinner designed" underfloor heating and the omission of the ladder radiator in the bathroom.

I have now thought about, preparing for the future, possibly having the underfloor heating laid more closely and having the ladder radiator installed in the bathroom (without it is probably not possible).
That would probably mean that I could also run the gas heating at a temperature of 35 degrees.

What do you think about this? Does one actually save effectively on gas heating if it can be run at 10 degrees lower? Does my approach make any sense at all? Or am I just filling the heating engineer’s wallet?

I would have it installed closer together. The advantage is that if you ever want to replace or convert the heating system, you only need to replace the heat generator. Otherwise, you close off a few options for yourself later. And the additional costs should be clearly limited.

Yes, additional costs would only be €1000, with the most expensive part being the ladder radiator in the bathroom. It is probably necessary to ensure that the room temperature becomes adequately high given the low temperature and the small area (just under 11 sqm).

For cost reasons, because we are already at our set budget limit and I do not share the madness of some to install a heat pump, more insulation, rainwater system and who knows what else at any cost ;) I think many things in this direction are simply a matter of belief... and I have read a lot, talked to other homeowners, and formed my own opinion on it. Therefore, we are installing a gas condensing boiler without solar. Gas is available on our property. We have about 3 meters of gas piping to lay to the house. Solar costs us an additional 5000 euros Air heat pump costs us an additional 8000 euros Geothermal heat pump costs us an additional 13,000 euros. When I calculate how long it takes for these technologies to pay off at these prices, the decision on what to install is easy. And even then, no one guarantees me that these technologies will run with the same effectiveness and reliability for 20 years. But that would be too much OT. I know there are many specialists here and I am very happy to be advised, that's why I am here, but I want to operate within a reasonable financial and economically sensible framework.

Hello,

For cost reasons, because we are already at our set budget limit and I do not share the mania of some people to install a heat pump, even more insulation, rainwater systems, and who knows what else at any price ;)

Yes, the internet knowledge ... you shouldn’t let yourself be influenced by it. More and more does not always make things better!

Where is your budget?

Solar costs us an extra 5000 euros
Air heat pump costs us an extra 8000 euros
Geothermal heat pump costs us an extra 13,000 euros.

Do you want to build a KfW house?

The price for the geothermal heat pump seems reasonable to me for a total drilling depth of 100.00 m or 2 drillings of 50.00 m each; I don’t understand the surcharges beyond that. Most providers today already have KfW 70 as standard; regardless of whether with a gas condensing boiler or air-to-water heat pump.

And even then, no one guarantees me that these technologies will run with the same effectiveness and reliability for 20 years.

Then you shouldn’t forget that a gas condensing boiler – because of the condensate – will not "live" as long as earlier gas heaters. What can break on an air-to-water heat pump or geothermal heat pump – apart from affordable minor issues perhaps – is unclear to me. Of course, you are right that there is no reliable data yet on the lifespan of the latter devices.

Rhenish greetings

We are building according to KfW70, which we can achieve without solar through a controlled residential ventilation system (Helios), which is required by the development plan anyway. I was also surprised by the surcharge for solar; at half the price I would definitely have considered it, but 5000 just doesn’t pay off.

Our budget is 180k, which we have already slightly exceeded. All extras are included in this. (130sqm floor area, gable roof, rectangular shape)

The air heat pump would be a combined device as a freestanding unit in the utility room for air heat and integrated controlled residential ventilation. Alpha Innotec LWC80. Maybe that’s why it’s so expensive... I could also get an offer for a freestanding unit outside.

As described, I think there are pros and cons to everything... if money were no object, I would opt for a geothermal heat pump... but with the uncertainties about lifespan and reliability, I currently see no reason to pay the extra cost. Also, since we have gas directly on the property and thus the connection costs (which are also subsidized by the local energy supplier) remain relatively low.