In 2025, households connected to heat networks will pay a maximum of 43.79 euros per gigajoule (GJ) for heating, which is nearly 3 euros less than the previous year. The fixed costs for standard users will see minimal change, increasing slightly from 759.88 euros to 760.77 euros annually. This information comes from the ACM's calculation of maximum heat tariffs, which suppliers must adhere to.

The ACM determines these maximum tariffs based on a legal methodology, ensuring that heat suppliers do not exploit the maximum rates for excessive profits. The 2023 Financial-returns Monitor indicated significant variability in returns among heat suppliers, ranging from -22% to +21%, with an average return of 1.03%. To gain further insights, ACM is currently studying five heat suppliers, with preliminary findings expected early next year.

The calculation of maximum tariffs is governed by the Dutch Heat Act and related regulations, linking them to the average costs faced by households using gas-fired boilers. The maximum tariff per GJ is derived from the average natural-gas price of fixed contracts starting January 2025. Fixed costs are calculated based on maintenance, depreciation, and operational costs associated with gas-fired heating systems.

In response to rising costs, the Ministry of Climate Policy and Green Growth has introduced an emergency bill aimed at making heat more affordable. This legislation modifies the maximum tariffs by excluding real tax increases on natural gas from variable tariffs and allowing ACM to use different reference dates for gas pricing. However, the impact of these changes is less significant than initially anticipated due to subsequent regulatory adjustments.

Additionally, a new Dutch heat act is in the pipeline, which aims to phase out the current pricing principle. While the exact implementation date is uncertain, it is not expected to take effect before 2026. For the initial two years, ACM will continue to set tariffs based on the existing pricing principle.