How much thermal insulation makes sense?
How much thermal insulation is sensible?
The energy efficiency of a building depends on several parameters. The most important are the geometry and the physical properties of the outer skin of the temperature-controlled rooms (walls, ceilings, roofs and windows). The windows also have the property of enabling heat gain in winter, but in summer they must be protected from solar radiation.
For new buildings, the building regulations stipulate minimum requirements for the building envelope, the result of which is reflected in the energy performance certificate. This raises the question of whether it makes sense to improve the insulation beyond this. It is important to know that the relationship between insulation thickness and energy savings is non-linear. This means that, in the best case scenario, the energy loss is halved if the insulation thickness is doubled. In principle, the costs and benefits can be calculated relatively easily. It is then up to the building owner to assess these parameters. The costs of the additional insulation thickness should then be compared with the predicted savings. The threshold values of possible subsidies should also be taken into account.
Future developments must be taken into account. A forecast is always associated with a risk, but from today's perspective, rising energy prices are to be expected due to the planned move away from fossil fuels. Passive houses no longer require conventional heating systems due to their good insulation.
At the time of construction, the additional costs for additional thermal insulation are manageable (only material costs), and retrofitting at a later date is uneconomical. So better more than less.
The question of sustainability should be included in the considerations. This includes the location and function of the property, as well as availability and the possibility of reuse or disposal of the respective building materials.
The comfort of a well-insulated building is a key quality factor, and its operation can be guaranteed with less effort in both technical and economic terms.
In the case of existing buildings, particularly uninsulated buildings from the post-war period, thermal refurbishment often makes economic sense, especially if scaffolding would have to be erected anyway for repair work on windows or the façade. Subsidies should also be taken into consideration here.
Sustainable considerations take into account costs, benefits and risks over the entire life cycle of a building. Better thermal insulation is associated with higher investment costs. However, this quality means a higher building value and lower operating costs.
