Tariffs for heat supply services to regulated merchants, in accordance with economically justified costs, shall be approved by the Public Utilities Commission (Regulatos). Additional information is available on the Regulator’s website: https://www.sprk.gov.lv/content/tarifi-4. The heating fee is calculated in accordance with the consumed volumes of heat energy recorded monthly by the general heat energy meter of the house located in the house input. The total consumption of heat energy of a residential building depends on several factors: 

• outdoor air temperature, including wind direction, wind strength; 
• temperature regime established in the individual heating unit of the building; 
• habits of the population; 
• technical condition of the building and other factors.    

Due to the above conditions, the amount of heating costs varies from one month to the other.   Also, the tariff for heating can vary significantly even in nearby houses, because heat energy is not only for heating the apartments, but also for heating water and for public positions (public heating/circulation/heatloss).  
In addition, each house uses different calculation algorithms, in accordance with external regulations and/or the decision of the community.