Starting this year, the Netherlands Authority for Consumers and Markets (ACM) will implement a new method for determining maximum heat tariffs, utilizing three reference dates: September, October, and November 2025. This change aims to reduce the impact of volatile natural gas prices on heating costs for consumers.

Previously, maximum heat tariffs were calculated based on the average natural gas price from a one-year contract starting January 1, using a single reference date at the end of November. The new approach averages prices from three different dates, which helps to smooth out fluctuations caused by geopolitical tensions or seasonal changes.

The maximum heat tariffs are linked to the average costs incurred by households using gas-fired boilers for heating and hot water. This pricing mechanism is governed by the Dutch Heat Act, the heat decision, and the heat regulation. Recent legislative changes have allowed ACM to adopt this more stable calculation method.

For the upcoming year, ACM will determine the heat price per gigajoule (GJ) based on the average prices from the top ten natural gas suppliers for one-year contracts on the specified reference dates. The weights for each reference date will be equal, ensuring a balanced approach to tariff setting.

In addition to the maximum heat tariff per GJ, ACM will also establish maximum tariffs for fixed costs, metering, and heat interface units. The authority plans to gather the necessary data over the coming months and aims to publish the maximum tariffs by the end of November.