The agony of choice...

Good evening dear homeowners,

after gathering one opinion after another for days now and also consulting a friendly heating engineer, choosing the suitable heating system is not getting any easier. I am now counting a bit on your experience :)

Framework conditions:

[*]New build single-family house (solid, Poroton T8/T9, monolithic construction if possible)
[*]Style city villa, 2 full floors + basement
[*]approx. 150 sqm living space
[*]plot with slight slope
[*]there is a gas connection on the property
[*]hipped roof with approx. 20° pitch, ridge line runs approx. from NNE to SSW
[*]according to local civil engineer, the terrain (rocky) is not very suitable for geothermal energy (collector), but I haven’t had a detailed examination done yet
[*]underfloor heating (according to installer, the build-up is approx. 14 cm including floor covering)
[*]we would like to install a central ventilation system

Does solar thermal exclude itself due to the roof pitch?
What would you recommend here as a heating system? I am mainly looking at the economic aspect.

Maybe you could also specifically recommend a system (maybe it also fits the current energy saving ordinance)? (Gladly also via private message).

I hope some of you dare to answer, I look forward to every reply.

Have a nice evening!

Maybe a small note: We would like to install a Swedish stove in the living & dining area (what is the opinion in the forum here, pellet or regular wood stove)?

Questions and more questions...

Gas with ST, air-water heat pump or brine-water heat pump. Get offers made. Is gas available on the property or in front of it? If it is fully developed, gas is most likely to be worthwhile. We only have 14 cm construction in the attic. In the ground floor, it is more due to insulation. How is the floor slab insulated for you? Do you have a planner for details? Do you have an expert on board? You should definitely show them the construction service description before signing the contract.

Good evening dear home builders,

after I have gathered one opinion after another for days now and have also asked a heating engineer friend, choosing the right heating system is not getting any easier. I will now list some of your experience values :)

Framework conditions:

[*]New single-family house (solid, Poroton T8/T9, monolithic structure if possible)
[*]Style city villa, 2 full floors + basement
[*]approx. 150 sqm living space
[*]Plot with slight slope
[*]There is a gas connection on the plot
[*]Hip roof with about 20° roof pitch, ridge line runs approx. from NNE to SSW
[*]According to the local construction supervisor, the terrain (rocky) is not very suitable for geothermal (collector), but I have not had a detailed investigation done yet
[*]Underfloor heating (according to installer the build-up will be approx. 14cm including floor covering)
[*]We would like to install a central ventilation system

Does solar thermal exclude itself due to the roof pitch?
What would you recommend here as a heating system? I am rather looking at the economic aspect.

Maybe you could also specifically recommend a system (maybe it also fits the current energy saving ordinance)? (Gladly also by private message).

I hope some of you dare to answer, I look forward to every reply.
Maybe a small note: We would like to install a Swedish stove in the living & dining area (what is the opinion in the forum here, pellet or normal wood stove)?
Questions upon questions...

Have a nice evening!

Hi,

You are already building according to the 2016 energy saving ordinance.
However, you do not write whether you are building a KFW house, or not using KFW funding. This does indeed make a difference! What standard is planned? KFW100 Energy Saving Ordinance 2016 or KFW55/40/40+?

The systematics of the energy saving ordinance is initially "system-free". Your house just has to meet the corresponding values. This is always – roughly speaking – a combination of envelope/insulation + used technology (--> primary energy demand).

Balancing this can hardly be done here in the forum as it requires extensive calculations. Your construction supervisor and/or an energy consultant must do this.

Thermal solar: Also works on your roof.
But don’t expect too much from it. A relatively high investment comes with a relatively low yield. The combination of vacuum tube collectors (expensive!) and domestic hot water + heating support promises the greatest yield because these collectors have a better efficiency and already work at less insolation in autumn/spring.
I myself only have solar thermal with domestic hot water support and conventional collector due to the KFW-70 certification at the time. Overall, it is just a toy that was expensive and will never pay off. For the environmental conscience it is good though – I also enjoy it.
Here in my area, some city villas with 20-degree roof pitch have solar thermal systems.

Controlled residential ventilation: The debates here are often controversial. Personally, I never want to do without my controlled residential ventilation. The system absolutely fascinates me. I personally think your plan to install such a system is good. Even my wife is – after initial reservations – completely enthusiastic about it now.

Gas connection: I myself am pro gas connection, that is my personal opinion. In the distant future, if my gas boiler breaks, I will replace it with a system that can also generate electricity (currently this technology is in its infancy + very expensive).
Even if the gas connection is on the plot, bringing it into the house will cost you several thousand euros.

You will probably find it easier to fulfill the energy saving ordinance by equipping the house with a good air-water heat pump (COP > 3.3) or wwwp. This even more or less cost-neutrally, as the additional cost of the system is offset by the savings on the gas connection. Additionally, you have planned underfloor heating, the low flow temperatures then also speak in favor of an air-water heat pump. Exact details, as said, must be told/calculated by your construction supervisor/energy consultant.

Swedish stove: If you ask 10 people, you will get 11 opinions.
Buy what you want, what you like. Pellet or wood. Pellet can be convenient because it is partly automatable.
In a modern house: properly dimension it, 5kW is enough, otherwise you will have a fixed sauna, but you surely want atmosphere and coziness and not to vent the heat of an oversized stove to the garden with open windows.
Save money with it? Forget it completely. The efficiencies are nicely calculated. Converted to energy content, both wood and pellets are more expensive than gas or electricity for an air-water heat pump. Only if you get wood cheaply/for free, it is worth it.
A real fireplace – you probably have room for it – would be an alternative.
Apart from that: I also do not want to do without my fireplace stove, it is my style of coziness when it is running and I can watch the flames.
The stove is – let’s be honest – simply a lifestyle event, nothing more.

Best regards
Thorsten

Is the gas on the property or in front of it?

The gas connection is already on the property

How is your slab insulated?

I can’t say yet, I haven’t gotten that far down there yet ;)

Do you have an expert on board? You should definitely show them the construction service description before signing the contract.

What exactly is a construction service description and an expert? :)

Which standard is planned? KFW100 Energy Saving Ordinance 2016 or KFW55/40/40+?

Since I don’t think the additional investment is worth it, I am currently of the opinion not to pursue Kfw financing; maybe I will be proven otherwise though :)

From which temperature do I heat entirely with electricity using an air-water heat pump?

Would it be a good choice to combine controlled residential ventilation and an air-water heat pump (Viessmann offers something like this) and power the air-water heat pump with a photovoltaic system?

Or is it more economical to rely on a condensing gas boiler and possibly expand it with a small air-water heat pump with photovoltaic? (My heating installer advised me on this setup)

Topic pellet stove: After having looked at a stove, I will probably revert to a conventional wood stove. As Thorsten already wrote, "atmosphere and coziness" – this effect simply comes through more with a wood stove. Above all, I enjoy watching the fire.

From which temperature do I heat entirely with electricity in an air-water heat pump?

When the pump is running, electricity is consumed... That's obvious, right?
Or how do you mean the question, electricity is always required otherwise the heat pump doesn't work