ᐅ Use an Air Source Heat Pump or Gas and Solar?

Hello Euro,
Hello Musketier

Thank you, Musketier, that’s exactly what I meant as well

€uro schrieb:

But even then, you can help with usual average values. [...]
Based on experience, after the initial enthusiasm fades, firewood chopping decreases after 2 to 3 years

Yes, it’s always tricky with experience and average values...

I have been chopping wood repeatedly for various "campfires" for over 12 years...
The average you used as the basis for your calculation is 2 to 3 years.
That results in a deviation from the forecast of 400-600%...

No offense, you’re basically right, but it’s not quite that simple...
No hard feelings

Best regards
Micha

Musketier schrieb:
.... How close do your calculations actually come to the real consumption?

In my opinion, very close, after adjusting for climate roughly +/- 15%. Achieving higher accuracy would hardly be possible with reasonable effort.

Musketier schrieb:
.... Have you ever calculated a system upfront and then recalculated after a few years to see if it was really the right decision?

The calculation is made in advance, and the actual situation is analyzed afterwards.
Not just one, but several systems in my region, including my own building, which is virtually “bugged” with sensors inside and outside. The better the input parameters are recorded, the more accurate the final result.

Musketier schrieb:
.... With the ‘botched practical systems’, you always have more insight than the planner because you know the actual figures.

If there had been any planning for these botched systems, it would have been very helpful for me and the owners. Usually, however, there is absolutely - Nothing! No heat load calculation, no measurement protocol for the controlled ventilation system, no radiator sizing, no pipe hydraulics...etc.
A complete vacuum, and this is exactly where the problem lies.

Musketier schrieb:
.... Do you know what information the owner gave the planner back then and which price increases were factored in?

Usually not, only in exceptional cases. The norm is the general contractor / main contractor project!
Counter question: Does your supplier ask you what room temperature you want in the living room, hallway, utility room, kitchen, etc.? Probably not, but still offers you House A with heating system XY at price Z. How is that possible?

Musketier schrieb:
.... Or I become more heat-loving with age and the average temperature ends up a few degrees higher than originally planned. How do you factor that in?

Higher room temperature => higher demand => higher consumption costs!
In moderately to well-insulated buildings => noticeable impact
In very well-insulated buildings => minor impact
With heat pumps => minor impact
With conventional heat generators => noticeable impact
In mild outdoor climate => minor impact
In cold climate => noticeable impact

Now you can set up a matrix for yourself.

Musketier schrieb:
.... If the heating doesn’t run at night during extreme cold, the temperature drops so quickly after switching off around 9:00 PM that I have to heat more beforehand than I actually need.

Simple answer: heat continuously at a reduced level! “Preheating” makes no energetic sense! The ideal heating system supplies just the amount of energy the building is currently losing. Most conventional heat generators in existing buildings are far from this. They cannot modulate and usually only operate On/Off! Hence the often significant losses.

Musketier schrieb:
.... I can’t even say what average temperature I currently have.

If you don’t know what you want, you have to live with the consequences.
Not knowing what you want or expect means guessing with an uncertain and sometimes costly outcome.

Best regards.

€uro schrieb:

If you don’t know what you want, you have to live with the consequences.
Not knowing what you want or expect leads to guesswork with an uncertain, sometimes costly outcome.

I want it WARM.

Whether I pay 10€ or 20€ more per month for that doesn’t matter to me.
At 100€ per month, things look very different.
That’s why the question was how far apart the systems are.
Your favorite “money pit” can mean a lot of things.

But I assume that heating 120m² (1300 sq ft) will definitely cost less than our current 80m² (860 sq ft) apartment, no matter which heating system I use.

The euro is making me a bit unsettled as well.
We have a standard house.
We have gas heating, solar panels, and radiators (no underfloor heating).
We have a controlled ventilation system (purely a comfort feature).
And we have a wood-burning stove (just for the cozy campfire atmosphere).

So far, I was really confident in what our house provider offers, and since we basically got the whole package for free, without high extra fees (of course they factored that in beforehand), I didn’t worry much. I also know some heat-loving customers of the provider who have moderate heating costs, which I currently only laugh about from my rented apartment.
But the more I read here, the more uncertain I become.

Joking aside... I firmly believe that reputable house providers have done the calculations and won’t sell you every nonsense. I also know that from an ecological standpoint, gas is not the smartest choice, but we want gas for cooking, so it’s definitely more practical than anything else. I also know that such a wood stove is probably too powerful for our house, and we will likely have to open everything up in winter first (or turn up the controlled ventilation) to get the heat out again. But there really is nothing nicer than watching the fireplace in the evening while reading a book. And chopping wood is really fun as long as you can still do it...

But I truly believe—and I am convinced—that no matter which heating system I had installed, the running costs would remain low in terms of energy consumption. The only thing I’m less convinced about is the solar system, but well, the KFW requires it, or else every other option would be more expensive.

So, on to the next step.

Musketier schrieb:
...Whether I pay 10€ or 20€ more or less per month for it doesn’t matter to me.
At 100€ per month, the situation looks quite different.

Today or in 15...20 years?
Until then: good job

Best regards

Der Da schrieb:
...But I truly believe, and am convinced, that no matter which heating system I had installed, the consumption costs would remain very low.

One should be satisfied with that and stand by their own conviction.
My comments are mainly aimed at those who are still undecided and looking for a suitable, cost-effective overall concept, rather than those who have already made their decision and where nothing can be changed anyway. General uncertainty is neither intended nor desired!

Best regards