How Are Central Heating Costs Allocated?

First, Identify Your Building’s System

• Heating and hot water from one boiler, with a hot water cylinder: First the fuel used for hot water is calculated and deducted from the total cost; the remaining amount is the heating cost.
• System with apartment stations: Hot water is produced not centrally but in the station in each apartment.
• Heating only: If the central system does not produce hot water, the entire cost is heating cost and you go straight to the 70% / 30% calculation.
• Hot water only (months when heating is off): Since the boiler only produces hot water, the gas cost is generally treated as hot water cost and shared according to consumption on the hot water meters.

Calculation with a Hot Water Cylinder, Step by Step

1. Calculate the fuel used for hot water

If heating and hot water are supplied by the same boiler, under the regulation the heating share is what remains after the hot water consumption is deducted from total consumption. The fuel used for hot water is found with this formula:

By = 1.20 × V × (tw − 10) ÷ Hu

• By: Fuel used for hot water (m³ for natural gas)
• V: Volume of hot water consumed in the building (liters)
• tw: Hot water temperature (°C)
• Hu: Net calorific value of the fuel (kcal/m³ for natural gas); under the regulation it is obtained from the fuel supplier.

The numbers 1.20 and 10 in the formula are fixed constants in the regulation. Multiplying the fuel quantity by the fuel unit price (F) gives the building’s total hot water cost: M = By × F. Entering 1,000 liters for V gives the cost of 1 m³ of hot water.

2. Distribute the hot water cost to the apartments

Under the regulation, all central hot water costs are allocated according to the measured hot water consumption of the apartments. An apartment’s share is the building’s hot water cost multiplied by the ratio of the consumption on the apartment’s hot water meter to the total of all hot water meters in the building.

3. Split the remaining heating cost into 70% and 30%

Deducting the hot water cost from the total gas cost leaves the building’s heating cost; the regulation denotes this amount by M. Under Article 8 of the regulation:

• 70% is allocated according to the apartments’ measured heat consumption,
• 30% is allocated according to the apartments’ heated floor area, to cover common areas, system losses, minimum heating and operating costs.

Consumption is not measured in common areas such as staircases, the entrance hall and the boiler room; the heat for these areas, pipe losses, minimum heating and operating costs are covered by this 30% share. For minimum heating, see our What Is the 15 °C Minimum Heating Limit? article. Each apartment’s area share is calculated as follows:

Area share = 0.30 × M × (A ÷ At)

A is the apartment’s heated floor area and At is the total heated floor area of all apartments in the building (m²).

4. Distribute the 70% consumption share according to the metering device

This step depends on which device is used in the apartments, and the values of the two devices must not be mixed.

In a building with heat meters: A heat meter measures the flow of water entering the apartment and the supply–return temperature difference, and shows consumption in an energy unit such as kWh or MWh. The apartment’s consumption share is:

Consumption share = 0.70 × M × (S ÷ St)

S is the consumption read on the apartment’s heat meter during the period (the difference between the latest and the previous reading), and St is the total consumption of all heat meters in the building. If every apartment is measured with a heat meter, this calculation gives the same result as dividing the 70% amount by the total kWh to get a unit price per kWh and multiplying it by each apartment’s kWh consumption. For how a heat meter works, see our What Is a Heat Meter? guide.

In a building with heat cost allocators: An allocator is fitted to each radiator and its display shows not kWh but a unitless share value. Under the regulation, the apartment’s consumption is found by reading all allocators in the apartment:

Consumption share = 0.70 × M × (S1 + S2 + … + Sn) ÷ St

S1…Sn are the values read on each allocator in the apartment, and St is the total of the values read on all allocators in the building. Allocator values are meaningful only when compared with other allocators in the same building; they may need to be corrected with factors for the radiator output and type. For details, see our How to Read a Heat Cost Allocator guide.

Buildings with mixed devices

If some apartments in a building are measured with heat meters and others with heat cost allocators, the kWh values of the heat meters and the unitless values of the allocators cannot be added together; they are different quantities and do not form a single “total heat consumption”. In this case the regulation (Article 7/5) requires first measuring total consumption and then determining the shares of the user groups whose consumption is measured with the same equipment. In other words, the share of each equipment group is found first, and then each group is allocated internally using the values of its own devices.

Worked Examples

The figures below are chosen only to illustrate the method; they do not belong to a real building. In both examples, the heating cost remaining after the hot water cost is deducted is M = 100,000 currency units, the total heated floor area of the building is 4,000 m² and the sample apartment’s area is 120 m². The apartment’s hot water share is added to these amounts separately.

Example 1: Building with heat meters

Assume the total period consumption of the heat meters in the building is 50,000 kWh and the sample apartment’s consumption is 1,000 kWh.

Example 2: Building with heat cost allocators

In a building where factors are applied or that works on the product scale, assume the allocators on the sample apartment’s three radiators counted 420, 310 and 150 units during the period; the apartment total is 880 units. The total of all allocators in the building is 22,000 units.

In this example, 880 units do not mean 880 kWh. The calculation is based not on a price per kWh but on the apartment’s ratio within the building total.

Systems with Apartment Stations

An apartment station (heat interface unit) uses hot water from the central boiler to provide both heating and domestic hot water inside the apartment. Domestic hot water is produced inside the apartment, in the station’s heat exchanger. Space can be provided in the station for metering devices such as a heat meter and a water meter.

Since hot water is not produced centrally in a separate cylinder, the calculation is not set up as in a system with a hot water cylinder. If the heat meter is at the station inlet, on the line coming from the central plant, the heat used to produce hot water in the apartment also passes through this meter and is included in the measured consumption. The details of the calculation depend on the location and type of meters in the building; you can check the method used in your building on your cost allocation statement.

What to Check on Your Cost Allocation Statement

The Turkish regulation lists the information that must appear on the heating and hot water cost allocation statements given to apartments. When checking your bill, look in particular at:

• The previous and latest readings on the heat meter or heat cost allocators, and the consumption between them.
• The building’s total cost, split into heating and hot water preparation amounts.
• The consumption-based and fixed allocation ratios of the heating cost, the amounts corresponding to these ratios and the amounts charged to your apartment.
• Your apartment’s area and the reading dates.

If a meter or allocator cannot measure correctly because of a fault, the regulation provides for that apartment’s share to be determined from its consumption in similar previous periods or from the consumption of similar apartments in the same period.

At Novus Energy we provide remote meter reading and heat cost allocation services for buildings with heat meters and heat cost allocators. For metering devices, see our Heat Meter and Heat Cost Allocator categories.