Which is more sensible: heat pump or insulation?

Thanks for the answers, I already suspected that it is not so easy to get a brief statement. The tip about the energy consultant is certainly not to be dismissed, but I have already had experiences in conversations some time ago that made me a “consultation-resistant”! Warning, I admit, subjective experience!: I don’t want to go into this further here, since there are of course also accurate consultants, but many (of the inexpensive ones) are de facto “pushy salespeople” who can nicely dramatize problems, want to make plans, measure the boiler room, etc. to justify the consultation effort in order to then be able to make corresponding offers, which of course are mostly company-specific for commission reasons.

After some time-consuming research, I have already found that the heat pump is good for the environment but unfortunately does not positively influence my heating costs that much, so I would probably switch to gas instead of a heat pump when moving away from oil. (A small additional remark: it is also relatively easy to import heat pumps from China yourself – not everything coming from the Far East is junk, of course you have to take care of some things, and the parts are surprisingly cheaper, so you can do without a subsidy – if you get one at all.) The currently sharply increased gas price certainly gives me a lot to think about for the future, which is why I have nevertheless done some online research on Chinese heat pumps.

Regarding the topic, as said 25 cm Ytong /120 m²/ underfloor heating/ oil consumption approx. 2000 liters per year. Unfortunately, the values are not cleanly reproducible because I have not insulated the basement ceiling. Thus, part of the heat radiates downward, and I heat the basement (fully basement) as well. As said, consultation-resistant, as all experts warned. In practice, however, proven! Because the basement can be used comfortably without radiators and installation. My floor therefore does not have a 35° flow temperature but 50° in very cold weather, but as said, I weakly heat the basement with it.

Sorry if I still want to simplify it. I now have about 2000 l oil consumption with the aforementioned 25 cm Ytong with U=0.35. Since the best saving opportunity is insulation, I intend to add additional external insulation. After research, the thickness of 6 cm (price/performance) is sensible (I know more is better, but the efficiency curve starts to flatten). The facing is made of polyurethane and would have a U-value of 0.21. Question: what is the effective value with stone 0.35 and insulation facing 0.21? The value should improve. When asking the companies, they always referred to “complicated higher mathematical calculations”, which I do not find understandable. If I had the new “total value”, I could relate it to the oil consumption and roughly calculate how much I could save. Even if it would not be exact, that is all that matters to me! I want to know what it brings me before I invest. For example, if I saved 200,-, that would be 2,000,- in 10 years and would not be in proportion to the investment. (Yes, I know nothing is too expensive for the environment.) Unfortunately, that was a bit too much text now, but I think it is clear what matters to me!?

Just calculate it yourself using tools like ubakus and TGA BIM. What the energy consultant does is no rocket science. You can compare cheap, self-installed Panasonic heat pumps and gas with a few Excel calculations. Underfloor heating already sounds good.

After some time-consuming research, I have already established that the heat pump is good for the environment but unfortunately does not positively affect my heating costs that much, so I would probably switch from oil to gas instead of to a heat pump.

It depends on where a) the electricity for the heat pump comes from and b) how much electricity you consume. Without energetic upgrading of the house, it will be similar with gas (although gas is rather more environmentally friendly than oil).

(Small additional remark: you can also relatively easily import heat pumps from China yourself.

Nonsense. Go to a f o r u m called htd and educate yourself about Panasonic monoblocks. Highly efficient at really manageable costs (the 5kW monoblock costs around 3k € at the German dealer).

On the topic, as said 25cm Ytong /120m²/ underfloor heating/ oil quantity approx. 2000 liters per year
The values are unfortunately not cleanly reproducible because I have not insulated the basement ceiling. Thus, part of the heat is radiated downwards and I also heat the basement (fully cellared).

Then you should consider insulating the basement ceiling. The simplest and most cost-effective way to save energy. My house is also not insulated from the outside, but the windows are new and the top floor ceiling + basement ceiling are insulated. With light sub-zero temperatures, 30 degrees flow temperature from the heat pump is just enough.

Sorry, if I still want to simplify.
I have now, with the above-mentioned 25cm Ytong with U=0.35, an oil consumption of ~2000 l
Since the best savings potential is insulation, I intend to apply additional external insulation. According to research, the (price/performance) thickness of 6 cm is reasonable (I know more is better, but the efficiency curve then flattens out slightly)

ubakus as a calculator for U-values. Keep in mind that additional insulation only accounts for a fraction of the costs. The so-called fixed costs are decisive. And you should also definitely insulate the basement.

The facing is made of polyurethane and would have a U-value of 0.21

What kind of insulation is that with these values? That would be new to me.

To:
1. ;) Electricity comes from my power outlet. Just kidding—and I already have 4000 kW per year. I have ruled out photovoltaics after thorough research and comparison with an acquaintance. I am at 53° northern latitude and my gable roof faces west! Even our top expert from TU Berlin (Quaschning lecture can be watched on YouTube) warned against comparing it only on a cost basis. Wish for everyone who has a heat pump -> may the coming winters continue to be warm. The aforementioned acquaintance installed an extra meter that shows how often and how long the auxiliary heating rods switch on – the power in watts is known – and found that the 5° limit is apparently somewhat optimistic. Fortunately, I do not have a new build but an existing building. Our world-saving "legislators" may not consider the additional costs of the energy saving ordinance as significant, but if in 2025 all new buildings are supposed to have photovoltaics, I do wonder who is going to pay for it.

2. Thanks for the tip, I checked it out, but the "affordable" parts are all in the low 5 kW range, with which I can’t manage 120 m². China was also just a tip (Alibaba) where I am still researching (transport costs), but there are parts with up to 80°! supply temperature. I am skeptical and currently corresponding about that.

3. Regarding basement insulation, I had already posted that contrary to the commonly propagated opinion at the time, I did not plan any special insulation (only slag as dead weight against ceiling vibration). Contrary to the specialists’ opinion, it has proven itself for years. Most of the heat from the underfloor heating rises upwards due to thermodynamics, and the downward losses are not considered losses but gains. I use the basement rooms and am glad that they are sufficiently tempered without additional heating installation! Of course, those who use the basement rooms only as a cellar (cooling wine bottles – Rothschild Chateau Lafite south-facing ;) delicious!) should pay attention to good insulation. Almost everyone I know, however, mostly uses the basement for hobbies, office, children, etc., and heats additionally.

4. Also thanks for the calculator program tips, which I checked out, unfortunately they all only calculate the "one U-value" and I have not yet been able to determine the combination of 2 values (insulation U1 0.35 // + insulation U2 0.21).

5. The 0.21 polyurethane is the 6 cm value of the company Boegerfassaden (insulation overlay with clinker design). It looks visually good in clinker design and you don’t have to additionally plaster the insulation! Unfortunately, it also costs a bit!!

In the neighborhood, someone applied this insulation and gave me the tip that he saves about 250 liters of oil (~15%) per year with his 100 m² house. Roughly extrapolated to my house, I then come to just over 200,- savings per year. So one can see that the savings claimed by the sellers for insulation should also be taken with caution in practice. Even if I assume 250–300, I come to 3,000 over 10 years. That does not appear to be a "hit" in terms of payback considering the costs for insulation and its installation. (Sorry if I look at it only from the money and not from environmental relief.)

I will keep my feet still and continue to research how the transport costs for heat pumps from China "free" to Germany are. Hopefully, the winter will be WARM!

4. also thanks for the calculator program tips, which I have looked into, unfortunately they all only calculate the "one U-value" and the combination of 2 values (insulation U1 0.35 // + insulation U2 0.21 I could not determine yet.

If you have time and enjoy it, then simulate everything in TGA Tools BIM

I would consult an energy advisor for the project. Because without calculation, the tables won’t help you either. And without knowing your heating system, you can’t advise what would be more sensible! Both insulation and heat pumps are currently heavily subsidized, both as individual measures and as a complete package with KfW level.

But you can. Tell me annual oil consumption, m2 living area, and m3 enclosed volume and age of your oil heating system. Hydraulic balancing? Possibly known flow temperatures? Underfloor heating or radiators? Based on this data, dimensioning can be planned with 90-95% accuracy. The remaining 5-10% only benefits you ecologically, not economically. Economically seems to be your priority. edit: just read the thread now nvm...