ᐅ Which is more effective: heat pump or insulation?

First of all, I want to clarify that my goal is not to save the world (sorry, my bad), but solely to reduce heating costs! I have been calculating back and forth for some time now but unfortunately can’t come to an optimal conclusion.

So here’s my attempt to use collective intelligence. Perhaps someone has already considered the same issues.

My house (old, 25cm (10 inches) Ytong blocks) could be improved in terms of U-value by adding a brick-style polystyrene cladding, or I could install a heat pump. Currently, I am heating with oil but could switch to gas. Oil heating still has a certain grandfathering protection for a while, but it’s likely that I will face problems with oil in the future.

Switching to gas would cost me about $8,000, the heat pump around $15,000. The polystyrene (or similar) cladding would indeed lower heating costs, but when I asked for information, no one could really tell me by what percentage my costs would drop if I improved the U-value (currently 0.35 for 25cm (10 inches) Ytong) by a factor X through additional insulation.

Are there tables or simple rough calculations that could help me decide without having to take another university-level math course first?

Thanks in advance for any information from someone who, like me, does not want to wait for the climate transition that will supposedly bring us winter temperatures of +15°C (59°F). 😉

I would involve an energy consultant in this project. Without proper calculations, the tables won’t be of much help. And without knowing your heating system, it’s impossible to advise on what would be more efficient! Both insulation and heat pumps are currently heavily subsidized, both as individual measures and as complete packages with KfW levels.

Do you have radiators? If so, and you don’t prepare properly beforehand, a heat pump *can* become an expensive undertaking. Insulation may be a prerequisite for a heat pump to make sense. You might also need to replace at least some of the critical radiators with larger models. The key point here is the low flow temperature.

Installing a heat pump blindly into an old building and hoping for the best can quickly turn into a money pit. A sensible sequence would be to first improve insulation and upgrade radiators, especially once the new government introduces attractive subsidy programs. After that, or simultaneously, you can switch to a heat pump.

Or you can stick with gas heating, where the flow temperature is not quite as crucial.

But simply applying insulation to the facade is not an option. What thickness is possible, and how are the window connections handled? Also, how old are the windows? An energy consultant is required.

Tell us more about the house. Implementing cost-effective measures requires a bit more knowledge.

Höhlenmensch schrieb:

Are there any tables or simple rough calculations that could help me make a decision without having to take a new university degree in mathematics first?

1. Energy demand of the current house
2. Supply temperature of the oil heating system
3. Type of radiators
4. Energy demand of the insulated house (only the facade or also the basement ceiling and top floor ceiling? Or already insulated?)
5. Wait for the assessment of an energy consultant
(6. Measures must fit the budget)

Simply replacing the oil heating system with a heat pump while keeping the old radiators can, in the worst case, mean spending a lot of money but ending up with higher heating costs (high supply temperatures are the biggest efficiency killer).
However, it might be enough to install new 33mm (1.3 inch) radiators and insulate the basement ceiling/top floor ceiling for the heat pump to be cost-effective.
But all of this is just speculation.