The law on co-ownership stipulates that the costs of insulation must be divided proportionately.

This is quite logical. If the communal parts of a building are insulated, all co-owners must share the costs. After all, every resident will enjoy the energy savings associated with such insulation.

Do the lower-level apartments benefit from roof insulation?

At first glance, it seems that residents on the top floor are the only ones who benefit from roof insulation. But better roof insulation has an impact on consumption in every apartment:

• Heat rises, and even passes through the floors between apartments.
• The better the upper apartments are heated, the more slowly the lower floors lose heat.
• So, every co-owner of the building benefits from good roof insulation because their apartment cools less rapidly.
• This influence does decrease the lower an apartment is in relation to the penthouse apartment.

Who benefits from premiums for insulation in a co-ownership?

In practice, the same ratio split is applied to possible energy grants. Another option is to allocate premiums to the reserves. But this is a decision that must be taken in the general meeting.

Who can decide to carry out insulation work in a co-ownership?

The law on co-ownership was amended on 1 January 2019. In concrete terms, this means the following:

• for work in the communal parts a 2/3 majority is required;
• for mandatory work to meet, for example, insulation standards, a 75% majority is no longer required, but a 50% + 1 vote is sufficient;
• other decisions will still require a 4/5 majority.