Besides lower heating costs it also protects the fabric of the facade and visually renews the building.
The scale of the cost is determined mainly by the total facade area, the thickness and type of insulation, and the scaffolding and labour costs. For a medium-sized panel building with 40-60 flats, full facade insulation is an investment of tens of millions of forints, so it is typically realised with grant funding or a loan.
To calculate payback, the difference between the old and new heat transfer coefficient must be applied to the heated area and the heating tariff. In practice well executed insulation can cut heating costs by 20-35 percent in a poorly insulated older building.
Importantly, the payback calculation should account not only for the heating bill but also for the value of protecting the facade: a neglected, cracked facade may require far more expensive emergency repair years later.
In financing it is worth checking the availability of panel renovation subprogrammes and other energy grants that specifically target external insulation and window replacement.
One practical point few consider: if scaffolding goes up as part of the project anyway, it is worth renovating balconies, railings or gutters at the same time.
For scheduling, a spring or autumn period with moderate temperatures is preferable, as most adhesives and renders cure optimally then.
Merbo's energy team prepares the payback calculation based on your building's actual data and shows how many years the investment takes to pay for itself.