Which heating system is currently the best?

.... Ultimately, however, all just theories; for a concrete statement, one probably needs a specific construction project with all details.

Correct, you hit the nail on the head!

v.g.

PS: Hello €uro )
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A few comments on this.

Two of the most important points for economical heating of a house:

1. The house should have as low heat loss as possible, because where nothing is lost, there is no need for expensive reheating.
Here "KfW55" is already a minimum standard (although that is a flexible term)... I would recommend "even better" (KfW40, passive house)

2. The heat demand and the maximum required heating capacity for the house (and the occupants) must be determined precisely enough. This cannot be done with the rough estimate of the builder!

Only after these points are addressed can one proceed to the selection/determination of the suitable heating system.
This includes not only the heat generator, but also the heat distribution (e.g. underfloor heating) and the entire system (hot water, distribution, storage, etc.).

A few things I've picked up here:

- Single-layer solid construction (without additional external insulation)
This usually does not achieve low heat loss and therefore no low heating costs.
It is "cheap" to build (if you don’t get ripped off) and that’s about it.
The savings are quickly used up but the insulating effect of the wall plays a role for an entire house lifetime...

- There is enough wood in Germany.
That’s nonsense. Everyone rushes to use wood – the heaters, the house builders, the furniture industry, the paper industry, and many more... even plastic is made from it.
Wood already partly comes from abroad today, otherwise our "huge wood stocks" would have shrunk long ago.

- Air heat pump as a cure-all
Where it fits the building, the occupants, and the climate region, the air heat pump can certainly be the first choice.
Unfortunately, these factors are given too little attention, which does not improve the reputation of the air heat pump (and heat pumps in general).
And the air heat pump quickly reacts here with quite high consumption costs if the framework conditions do not fit.
Actually, it is like what is written above about the solid wall without additional insulation: Eventually, the initial savings are used up (faster and faster with rising energy costs) and the air heat pump then no longer turns out to be the first choice.

- Oil and pellets
To me, these are out for single-family house construction.
Pellets at most if several houses are heated together (i.e. rather a large system) or as automatic supplementary heating, e.g., for peak loads (individual stove or integrated in heating).

- Brine and air heat pump
Should always be considered, the air heat pump somewhat more critically.

- Gas
If someone just wants cheap and does not want to invest in the future, this could be an alternative.

- Solar thermal
Very small systems for hot water are hardly profitable... only interesting for the Energy Saving Ordinance/KfW achievement.
In combination with heat pumps always unprofitable.
Often advantageous in combination with wood or pellets.
Advantageous with high hot water demand, especially in summer (e.g. pool).
Ecologically and possibly also economically very good may be very large solar thermal systems that cover e.g. 70-80% of the total heat demand. The initial costs, however, are very high.

- Photovoltaics
A photovoltaic system is not a heating system but a power plant.
One should always consider this separately from heating – like an investment.

Regards
-Martin-

Very interesting aspects. In summary, one should therefore choose an air heat pump and operate it with the electricity from a [Photovoltaik Anlage]. Then you heat almost cost-neutrally.

In summary, one should choose an air heat pump and operate it with electricity from a photovoltaic system. Then you heat almost cost neutrally.

Nice when all you energy savers primarily think about operating costs. However, there are apparently a few builders who have to work with a limited budget for the investment costs. At least for me, terms like payback period, profitability, depreciation, debt service and interest have a meaning. And that already begins with the question of whether a filled, porous high-hole brick T8 will ever pay off compared to an unfilled T10. (approx. 5 kWh/year additional consumption per sqm for approx. 240 sqm for a townhouse with 160 sqm = 1200 kWh/year = approx. €85/year with gas). Or whether the extra €10,000 to €20,000 for a heat pump will ever pay off during its lifetime, etc. etc........ Do I really need a specialized energy consultant for this consideration or shouldn’t they only come into play when it comes to optimizing the technology?

Very interesting aspects.
In summary, one should therefore choose an air heat pump and operate it with electricity from a photovoltaic system. Then you heat almost cost-neutrally.

No. That is too simplistic and "window dressing."

One should operate the heating system that results in the lowest total costs in the long term (at least 15 years) compared to other options, and not ignore ecological effects.
This includes both investment and operating costs, but also credit costs, expenses for risk coverage, etc. And in cost forecasting, one should also consider unfavorable developments (very high energy prices) since one still has to pay in such cases.

If you absolutely want to consider photovoltaic together with heating:
What use is a financial photovoltaic system that yields, say, 5% return if you simultaneously choose a heating system that, for example, causes 30-40% higher consumption?

You only heat cost-neutrally if the photovoltaic system generates enough to pay for itself and additionally produces a sufficient amount of electricity for the heating.
But such a large system does not fit on a single-family house.

@o.s.

Your approach regarding the factors for the calculation is initially good. But after that, you fall into a simplistic calculation. (by the way, where do the 5 kWh/a of additional consumption come from?)

A better U-value does not simply have a directly proportional effect on energy demand. There are also effects such as a smaller heating system, the possibility of different heating systems, more favorable parameters (e.g. lower flow temperature), etc. In addition, a wall surface temperature close to the indoor air temperature is an effect that, once you know it, you hardly want to miss anymore.

Actually, you should not only consider the heating as a whole system, but the house, the heating system, and the occupants together. Different wall constructions (etc.) can certainly be comparatively included here.

If you do not just deviate from T8 to T10, but instead build the walls as concrete slabs, then you save even more investment. Then put in wood and oil stoves (if compliant with the Energy Saving Ordinance) – it does not get any "cheaper" than that. Just be careful that your wife doesn't run away from you... then the calculation no longer works.

An energy consultant can only assist you with the concept. And there is nothing wrong with that.

For optimal technical planning, however, you need a planner for "Technical Building Equipment" (TGA planner). The energy consultant cannot and does not do that.

And if it is really about the investment sum, then you should question the house size and type of construction. Perhaps independent and/or expert advice can also help you realize more on less space or find a construction method that combines good thermal insulation at a good price (think of KS + ETICS or possibly also timber construction).

Again: You want to build "only with T10" – completely without additional thermal insulation? Then you could also buy a house from the mid-1990s, you wouldn’t have to build new, because you would get something like that and for significantly less money than a new build (including ancillary costs).

I strongly advise everyone against building with no or only little thermal insulation!