This is how we calculate the costs for the bill.

The total energy costs of the building where you live are settled with your landlord by the heat supplier every year. On behalf of your landlord, ista ensures the fair distribution of the total costs in accordance with the NEN-7440 standard. The calculation consists of several steps, which we explain below. Your landlord or manager provides the data with which ista makes the distribution. These are the total costs and the necessary resident data and moves.

The total cost of the building

Your landlord or manager states the total fixed costs of the entire building. By ista, the total costs are split into two parts. One part is divided among the residents' consumption. The other part is the fixed costs, which are distributed via a fixed factor, such as the floor area of the houses.

Typically, 65% of the total costs are distributed through consumption and 35% through the fixed factor. This is an agreement between your landlord or manager and ista.

A calculation example

To find out what costs belong to your consumption (your units), ista first calculates the price per unit. 
Suppose the variable costs are: € 65,000.00. (So 65% of the total costs)
And the total units in the building are 87,000 units. 
Then 1 unit costs: 65000 : 87000 = € 0.7471
We multiply this price by your units. 
For example, if your home has consumed 800 units, your consumption costs are: 800 x 0.7471 = €597.68. 

For the fixed costs (35% of the total costs), we calculate the costs per fixed factor. 
Suppose the fixed costs are: € 35,000.00 and these are divided over the floor area. 
For example, the total surface area of all homes is 7,000 m² 
Then 1 m² of floor area costs: 35,000 : 7000 = € 5.00
For example, if your home has a floor area of 70 m², your fixed costs are: 70 x 5.00 = €350.00.

For the settlement, your consumption costs and fixed costs are added together.