Underfloor heating and mechanical ventilation with heat recovery (MVHR), replacement of ordinary radiators

So we decided on gas heating for 2 reasons... we don’t like underfloor heating because of "warm feet" and a heat pump would have cost us 12,000 more. But as always, it’s individual and we also got a special deal that made gas even a bit cheaper. And a third fact: we love cooking with gas... so we killed several birds with one stone

Hello,

with an underfloor heating operated by a heat pump, there’s no such thing as "warm feet". If the floor is maybe 25 degrees, that’s significantly less than your body temperature, and you don’t perceive that as warm. A surcharge of 12,000 euros for the heat pump including drilling could be accurate. The drilling cost us about 8,500 euros including connection and filling. This investment usually refers to the lifetime of a house.

Regards...

So the prices still seem to be very different. The drilling (2x60m) cost me 4000€. The gas connection was mostly waived with about 2000€ and the token ST system is also omitted! And the warm feet with underfloor heating are still from the times when the underfloor heating ran with high flow temperatures!

Hello,

you got a good price for the drilling. For us, also 2x60m, it was just under €8,500 including complete trenching/passing through the basement/connection to the heat pump/filling with brine/commissioning of the heat pump. Although it was hard rock (gneiss), the price was fixed beforehand.

Regards...



Regards...

There is no offer available. It is from a general BB of a certain FH manufacturer.
Energy standard should be KfW 70 or 55.
By high operating costs I mean the electricity costs for the heat pump. You really need true professionals for that, otherwise it can get quite expensive.

Correct planning is necessary for every heat generator.

Why is that not possible? They are probably separate heating circuits. You can control them individually.

Even with controlled residential ventilation/WRG, there is a constant air exchange, and large temperature differences are therefore not possible.

I have also heard that the drilling is supposed to be very expensive. €15,000 or so is already included. I can heat with gas for a long time with that.
I once dealt with air-water heat pumps, but I have heard too many negative opinions about them.

You cannot generalize the costs for drilling. 2x100m is certainly more expensive than 2x60m. Furthermore, it depends on what services (connection to the heat pump, etc.) are included.

This only concerns the hot water now. What about heating when it actually runs constantly in winter? How high will the consumption probably be?

Yes, correct, hot water for 4 people, daily showering. What use are my heating costs to you if your house/area/desired temperatures/region (AT) are probably quite different? Have your heating load calculated exactly, then more can be said about the heat generator.

Regards...

Hi!

What does WE actually mean?

Assuming I am building with a general contractor FH manufacturer. Do they calculate the heating load for my house in advance or do they simply install their standard 08/15 gas condensing boiler.
And what if I want underfloor heating instead of the normal radiators. That surely changes the dimensioning of the heating system as well, right?

Hello,

WE = heat generator

I can only say how it was with us. We contracted the entire heating system ourselves. The heating engineer had the technical data of the house (manufacturer), i.e. areas, U-values, etc. From us, the desired temperatures, number of people, etc. Then he calculated the heating load. The size of the heat pump and the drilling depth were determined accordingly.
I could imagine that the FH manufacturer installs the complete standard 08/15 system in all-in offers based on various experience values, of course depending on the house size/model/location, etc. But as is often read in forums, caution is sometimes advised here, because consumption figures are "massaged" and calculated that are never achievable in practice.

Of course, the choice between radiators or underfloor heating is important for the heat generator and its sizing. Operating a heat pump with radiators is usually not ideal since higher flow temperatures have to be produced. With underfloor heating, it should not be more than 35 degrees. That is why underfloor heating as surface heating is actually a requirement for the use of a heat pump.

Regards...

What does WE actually mean?

Heat generator.

....Assuming I build with a GU FH manufacturer. Do they calculate the heating load for my house in advance or do they simply install their standard 08/15 gas condensing boiler?

They mostly install a heating system that somehow and exclusively produces heat. This sometimes leads to grotesque system concepts, e.g. Kfw 70 with an AWP! The focus is on sales according to their own calculations. Energy efficiency or economic viability for the builder is rather a foreign word there.

....And what if I want underfloor heating instead of the normal radiators? The dimensioning of the heating system must change as well, right?

Absolutely correct. The standard heating load or room heating loads do not change because of this, as they are independent of the heat generator (controlled residential ventilation with/without heat recovery must be taken into account!). However, the actual energy consumption, the heating surfaces, and thus the pipe hydraulics do change. With precise planning, the floor construction also changes and, if necessary, the wall construction for heat recovery! The seriousness of the provider can be easily recognized if they make no statements about this. This is likely significant for > 99% of the GU available. It is not for nothing that clever builders take this trade out of the contract and commission it externally after precise planning/dimensioning.
Best regards.
NB: Saving energy costs begins with the selection of the building plot!

...As is often read in forums, caution is sometimes advised here because consumption values are "adjusted" and calculated that can never be achieved in practice.

Correct, because essentially it is about removing the customer from the market. Almost all sales tricks are suitable for this.

...For underfloor heating, it should not exceed 35 degrees. Therefore, underfloor heating as a surface heating system is actually a prerequisite for the use of a heat pump.

Correct! Addition: In bathrooms, additional heating surface areas or other energy sources are often required.

Regards