Overview

• While there is no statutory start date, Oct. 1 to April 30 is the accepted heating period in which landlords must enable about 20°C in living rooms by day, 18°C at night and 21°C in bathrooms, with rent reductions possible if standards are not met.
• co2online reports higher 2025 running costs: pellets up 20%, gas up 15%, heat pumps up 5% and oil up 3%, with typical annual bills for a 70 m² flat at roughly €1,180 (gas), €1,055 (oil), €740 (pellets), €715 (heat pump) and about €1,245 for district heating (+2%).
• Experts cite rising CO2 prices and a shrinking gas customer base that pushes network fees onto fewer users, prompting warnings that gas and oil systems risk becoming cost traps over time.
• Guidance on when to switch on heat depends on building standard rather than a single outside-temperature rule, and underheating raises risks of mold and even frozen or burst pipes.
• Households can cut costs by roughly €400 a year through habits and low-cost fixes such as short, wide airing, keeping radiators clear, cleaning and bleeding heaters, sealing drafts, using smart thermostats and pursuing measures like hydraulic balancing.