Economic efficiency construction costs vs heating costs

Hello,

I am currently wondering how it would be practically possible to adhere to the ideal sequence for building a house in order to maintain as precise an economic efficiency as possible for the various components within the agreed budget.

Many homeowners always ask themselves the question "Is it worth it?". But unfortunately, the answer comes much later when the damage is already done.

For me, the heating load calculation (HLB) is a central answer for the economic efficiency of a house or its components. However, this is only done when all components have already been determined or even built. With the prefab house supplier/general contractor/main contractor, it probably becomes even more expensive to have such flexibility.

We have about €10,000 left, which we now want to invest sensibly. The first thought was to improve the masonry. From T9 (unfilled) to a T7 (filled). This is supposed to save real money later.
Assuming we have an offer from the mason ... €4,000 surcharge compared to the T9. Actually, only the HLB can roughly tell me in how many years the saved heating costs will have neutralized the surcharge. I am aware that it also depends on how efficient my heating system works converting electricity to heat, how cold it will be in the coming years, etc. But you still get a rough figure. Not to forget, that the investment will also cost interest, which will have a compound interest effect over the years of repayment. But all of this can be calculated ... theoretically.

So would it help to do the HLB in advance and evaluate it with various values and the corresponding costs? Which again is not exactly cheap to commission ... and I believe that is the main reason why this is not done in practice, right?

Morning

I think that in this area people always/often ponder about profitability
and in the equipment area, because that is how it is intended, the money sometimes goes out like that.

Olli

Why do you have 10 grand left over even though nothing has started yet?

No one is stopping you from hiring a TGA engineer who will then work out your desired concept together with your architect - it just costs money. You can also roughly estimate the heating load yourself - simply multiply the m² of exterior wall by the U-values and the temperature difference. By the way, the heating load does not necessarily tell you what your actual heating costs will be - it is only the maximum load at the design temperature. If you register at U-Wert, you can input your building into the heat demand calculator and modify the U-values as you like - here you can quickly see what benefits you get (at least in theory).

If you have 10,000 euros left over, the alternative is of course always not to spend the money ;-) What always works, though, is putting a few kWp on the roof.

Morning

I think in this area people always / often ponder about cost-effectiveness
and in the equipment area, because that's how it's intended, the money is spent like that.

Olli

Why do you have 10 grand left over even though you haven't started yet?

The estimate for the heating system is 10,000€ above the 4 offers I have received so far.

If you have 10k€ left over, of course there is always the alternative not to spend the money ;-)
What is also possible is a few kWp on the roof.

I have already thought about that too, but it might be more sensible to reduce electricity consumption than to produce more electricity ;) Especially the cost-effectiveness of photovoltaics is not really certain.

The problem is also that if I insulate too much, I might get a ventilation problem. Because a controlled residential ventilation system is absolutely out of the question!

If your house was built properly, it is airtight and without [Kontrollierte-Wohnraumlüftung] you will probably have to ventilate a lot - I would think about that again - by the way, insulation has not much to do with that. I am happy to report about our decentralized [Kontrollierte-Wohnraumlüftung] as soon as we live in the house ;-)

We have about €10,000 left over, which we now want to invest sensibly.

Well then, start building first... I rather think you will need another 10k... at least that was the case for us and many, many others here in the forum and everywhere else too...

There are always unforeseen expenses/bills coming up