Dämmen nicht mehr nötig? Experte erklärt Kostenvorteil durch Wärmepumpe

Heat pumps are considered a key energy-efficient technology. Their particular advantage lies in their high efficiency: depending on the design, they generate three to five kilowatt hours of heat from one kilowatt hour of electricity. Compared to gas or oil heating, the calculated energy requirement of a house can be significantly reduced.

Renovation calculator for maximum energy efficiency

This is exactly where the discussion begins. Alex Boerger, blogger and operator of the YouTube channel “smart energy saving” checks in his latest video, which renovation measures will be worthwhile in 2026. If a heat pump already massively reduces energy requirements, many homeowners ask themselves whether additional insulation measures are still necessary or make economic sense.

To answer this question systematically, the YouTuber has one specifically Renovation calculator developed that combines different measures and compares their costs, savings and payback periods.

A heavily unrenovated single-family home with extremely high heating energy requirements serves as a reference. In practice, such buildings either have very high heating costs or are only partially heated for cost reasons. The model not only takes theoretical demand values ​​into account, but also realistic consumption scenarios.

Cheap insulation measures are particularly practical at first

The calculations quickly show: A complete energy renovation with a new roof, facade insulation, floor slab insulation and new windows is expensive. Despite subsidies, the payback period is often several decades. For many owners, this approach is not economically viable, at least not just in terms of the heating costs saved.

So-called low-investment insulation measures perform significantly better. These include, for example, the insulation of the top floor, the core insulation of double-shell external walls or the insulation of cavities in roof and wooden beam structures. Such measures are comparatively inexpensive, technically established and possible in many existing buildings. In some cases they pay for themselves after just a few years.

In these cases, thermal insulation composite systems are worthwhile

The core insulation is particularly noticeable in double-shell masonry, which is present in a significant part of the German building stock. Significant savings can be achieved here with manageable investments. On the other hand, expensive solutions such as thermal insulation composite systems or a completely new roof are usually only worthwhile if there is a need for renovation, for example due to leaks or structural damage.

Advantages of a heat pump for insulated buildings

A crucial point is the interaction between insulation and heat pump. If the heat requirement decreases through targeted insulation measures, the existing radiators are often oversized. This enables lower flow temperatures – a key efficiency factor for heat pumps.

Furthermore, well-insulated buildings benefit from higher thermal inertia. They cool down more slowly and are therefore more resilient to fluctuating electricity prices, for example with dynamic tariffs or during dark periods. Heating operation can be made more flexible over time without immediately affecting living comfort.

The combination of insulation and heat pump pays off

The conclusion from the model calculations is sober: Insulation is not superfluous, but it is also not an end in itself. Instead of blanket, complete renovations, targeted, economically sensible measures are the more effective way. In combination with a heat pump, not only can costs be reduced, but efficiency, comfort and security of supply can also be improved in the long term.