Heating season in Zagreb 2026/27: when the heating comes on

When the heating season starts and ends

The heating season starts with a readiness period, on 15 September at the earliest, and lasts until 15 May of the next year at the latest (Rulebook on the general terms of heat delivery, Art. 11(2)). When the heat actually comes on is the distributor's decision, made when the weather calls for it (Art. 11(3)). The rulebook names no outdoor temperature and no number of days.

For the 2026/27 season HEP-Toplinarstvo published:

• 4 May 2026: readiness for the 2026/27 season officially starts on 15 September 2026, and the heating then comes on with the weather.
• 9 October 2026: from Monday 12 October 2026 the heating is turned on gradually in Zagreb, Osijek, Sisak, Velika Gorica, Samobor and Zaprešić. Kindergartens, schools, health centres and care homes come first, then buildings where work on the installations is finished and which are ready to take heat.
• The season ends on 15 May 2027 at the latest, on a date set by the weather.

So the heating doesn't come on in every building on the same day. We don't predict dates for future seasons: HEP publishes them every year in its news.

A building can ask for heat earlier

Heat is delivered to the flats by the building's heat buyer, which buys it on the owners' behalf and runs the internal installations (Heat Energy Market Act, Arts. 3 and 11). In most Zagreb buildings on HEP's network that is HEP-Toplinarstvo, but a building can pick another heat buyer registered with HERA. Delivery to the flats starts when the co-owners' authorised representative asks the heat buyer for it in writing (delivery rulebook, Art. 11(4)).

• Earlier: a building on a shared meter can get heat during the readiness period, before the distributor's decision, when the heat buyer asks in writing (Rulebook on the general terms of heat supply, Art. 23(3)).
• Outside the season: on the co-owners' representativeCo-owners' representative (predstavnik suvlasnika)simplifiedThe co-owner whom a building's owners elect to represent them in running it and to work with the manager. An owner must report a change of tenant to them within 15 days.Source: Zakon o upravljanju i održavanju zgrada (NN 152/24, 47/26), čl. 41. i 42., checked 19 Oct 2026More in the glossary's request, if it is technically possible. The distributor may approve or refuse it depending on the network's capacity (delivery rulebook, Art. 11(5)).
• In its 2026 notices HEP asks the representative or the building managerBuilding manager (upravitelj zgrade)simplifiedThe company or registered trader the co-owners choose to run the building. It allocates and collects the reserve fund and organises maintenance and emergency repairs.Source: Zakon o upravljanju i održavanju zgrada (NN 152/24, 47/26), čl. 41., 49.–52., checked 19 Oct 2026More in the glossary to confirm in writing that work on the installations is finished and they are sound. That is HEP's procedure from its notices, not a rule in the rulebook.

A tenant can't ask for this directly. If you're cold and the building isn't on yet, ask your landlord to contact the co-owners' representative or the building manager.

How warm it must be: day and night mode

• Day mode, 6:00 to 22:00: enough heat to reach the rooms' design temperatures under the technical regulations. The rulebook gives no number of degrees (Art. 12(2) and (3)).
• Night mode, 22:00 to 6:00: enough heat for an average temperature above 15 °C ± 1 °C (Art. 12(4)).

HEP recommends about 20 °C in a flat and says each degree more uses about 6% more energy. That's a recommendation, not a legal temperature.

A change of mode or temperature for the whole building is requested in writing by the co-owners' representativeCo-owners' representative (predstavnik suvlasnika)simplifiedThe co-owner whom a building's owners elect to represent them in running it and to work with the manager. An owner must report a change of tenant to them within 15 days.Source: Zakon o upravljanju i održavanju zgrada (NN 152/24, 47/26), čl. 41. i 42., checked 19 Oct 2026More in the glossary, if technically possible (Art. 12(5)). Complaints about heat quality also go through the representative in writing: the heat buyer measures within 3 days and reports within 8 more. The person complaining pays for the measurement if the complaint is unfounded, and the heat buyer pays if it is founded (Art. 13).

When the radiators stay cold: in the flat, the building or the network

First check it's a fault at all: until the building is turned on, or while HEP waits for its readiness statement, the flat stays cold even though the season has begun. At night the rules only guarantee an average above 15 °C ± 1 °C. If it is a fault, who to call depends on where it is:

• In the flat (radiator, radiator valve, thermostatic head): these are the end customer's installations (delivery rulebook, Art. 2(2)(3)), which the flat's owner looks after (Art. 10). The tenant tells the landlord without delay and lets them in for the repair (Housing Lease Act, Arts. 14(3) and 16; Civil Obligations Act, Art. 554(4)).
• In the building (risers, pipes, the substation): these are common parts of the building (Building Management and Maintenance Act, Art. 18), and a fault in the central heatingDistrict heating (centralno grijanje)Heating from a plant that supplies many buildings through a heat network. In Zagreb HEP Toplinarstvo sends the bill, and the cost is split among the building's flats.Source: Zakon o izmjenama i dopunama Zakona o tržištu toplinske energije (NN 67/2025), čl. 2., checked 19 Oct 2026More in the glossary is an urgent repair the co-owners pay for in proportion to their shares (Art. 25). Report it to the building managerBuilding manager (upravitelj zgrade)simplifiedThe company or registered trader the co-owners choose to run the building. It allocates and collects the reserve fund and organises maintenance and emergency repairs.Source: Zakon o upravljanju i održavanju zgrada (NN 152/24, 47/26), čl. 41., 49.–52., checked 19 Oct 2026More in the glossary or the co-owners' representativeCo-owners' representative (predstavnik suvlasnika)simplifiedThe co-owner whom a building's owners elect to represent them in running it and to work with the manager. An owner must report a change of tenant to them within 15 days.Source: Zakon o upravljanju i održavanju zgrada (NN 152/24, 47/26), čl. 41. i 42., checked 19 Oct 2026More in the glossary and to the heat buyer (HEP-Toplinarstvo in most buildings). The heat buyer must fix a fault outside the end customer's responsibility within 24 hours of being told, unless the fault's nature makes that objectively impossible (delivery rulebook, Art. 27).
• On the network: HEP-Toplinarstvo takes reports of no heat around the clock on the free number 0800 1003 (no heat). The distributor must give notice when a network fault is expected to cut heat for more than four hours, and publish the expected length in the media when many customers are affected (Art. 24). On 14 October 2026, for example, heat to Novi Zagreb and eastern Zagreb was cut for a while, and it was back for everyone there on the morning of 15 October.

The landlord makes repairs needed to use the flat at their own cost and in time, and the tenant bears small repairs and the costs of ordinary use (Civil Obligations Act, Art. 554). Damage the tenant causes is the tenant's to pay (Housing Lease Act, Art. 15). If the flat can't be used, or its use is much reduced for a long time, through no fault of the tenant, the tenant may ask for lower rent, and end the lease if it isn't fixed within a reasonable time (Civil Obligations Act, Art. 555). The lease settles the rest. Report a fault in writing, for example with our repair request; who pays for what in a flat is in our who-pays guide.

Inspections and tests in the building may stop the heat for up to four hours during the season, on the co-owners' representative's written request; longer work that isn't urgent is planned outside the season (delivery rulebook, Art. 20).

Why the heat bill comes in summer too

A HEP-Toplinarstvo bill for a building on the heating network has four parts: delivered energy, capacity (power), the supply fee and the heat-buyer fee. Energy changes each month with the heat delivered for heating and hot water. Capacity and the fees are the fixed part: HEP bills them every month in equal amounts, summer included.

Capacity covers fixed costs of production and distribution, such as maintenance and depreciation, that don't depend on use. HERA's 2026 tariff methodologies (NN 26/2026) also have a capacity item in euros per kW a month. Hot water is billed all year. In the heating season, where it isn't metered separately, HEP calculates it from the June-to-August average of the two previous years.

Prices, and how the cost is split in the building, are in our utilities guide and the guide to heat cost allocators.

Gas, district heating or electricity: how rentals are heated

How many active listings state gas, city heating, a heat pump or electricity, by district and next to the asking price per m², we count every day in our story How Zagreb rentals are heated. The shares are of the listings that state a heating type, and we show separately how many don't say.

The label “city heating” means the ad mentions the heating plant, city or district heatingDistrict heating (centralno grijanje)Heating from a plant that supplies many buildings through a heat network. In Zagreb HEP Toplinarstvo sends the bill, and the cost is split among the building's flats.Source: Zakon o izmjenama i dopunama Zakona o tržištu toplinske energije (NN 67/2025), čl. 2., checked 19 Oct 2026More in the glossary, or HEP-Toplinarstvo. It doesn't prove whether the flat is on HEP's central network, a closed system or the building's own boiler room. An ad that only says “etažno” (per-flat) or “centralno” (central) doesn't say where the heat comes from.

We don't judge which type of heating is cheaper, because that depends on the flat, the building and your use. For a flat with a gas boiler, see our gas boiler guide.

What to ask before you sign

• how the flat is heated and who sends the bill
• the bills for last winter and for the summer months
• whether the flat has heat cost allocatorsHeat cost allocator (razdjelnik)A device on a radiator that records how much heat a flat uses, so the building's district-heating bill can be split among the flats. It isn't a billing meter.Source: Zakon o izmjenama i dopunama Zakona o tržištu toplinske energije (NN 67/2025), čl. 2. i 31., checked 21 Oct 2026More in the glossary or a heat meter
• who the co-owners' representativeCo-owners' representative (predstavnik suvlasnika)simplifiedThe co-owner whom a building's owners elect to represent them in running it and to work with the manager. An owner must report a change of tenant to them within 15 days.Source: Zakon o upravljanju i održavanju zgrada (NN 152/24, 47/26), čl. 41. i 42., checked 19 Oct 2026More in the glossary and the building managerBuilding manager (upravitelj zgrade)simplifiedThe company or registered trader the co-owners choose to run the building. It allocates and collects the reserve fund and organises maintenance and emergency repairs.Source: Zakon o upravljanju i održavanju zgrada (NN 152/24, 47/26), čl. 41., 49.–52., checked 19 Oct 2026More in the glossary are, and whom you report a fault to
• with a gas boiler: who pays the chimney sweep and the service

The heat bill is in the owner's name: HEP's FAQ names only the owner of a home as the payer for households. If you pay the utilitiesUtilities (režije)Housing costs on top of rent: electricity, gas or heating, water, waste, the reserve fund, the HRT licence fee and internet. The lease decides which the tenant pays.Source: Zakon o najmu stanova (NN 91/96 … 105/20), čl. 5., checked 19 Oct 2026More in the glossary, agree with the landlord how the bills will be passed on to you. Take our viewing checklist to the viewing.

Frequently asked questions