Calculation of heat costs: A practical step-by-step guide

Accounting for heating costs is one of the most complex and at the same time most often disputed topics in real estate management. It generates hundreds of complaints and disputes between owners, tenants and administrators every year. At the same time, the accounting principles are logical - you just need to understand and apply them correctly.

In this detailed guide, we will guide you through the entire heat accounting process step by step. We will explain the legislative framework, show specific calculations with real numbers and advise how to solve the most common problems and complaints.

Legislative framework

Key regulations

Accounting for heat costs is regulated by:

• Act No. 67/2013 Coll. – on services connected with the use of apartments (basic framework)
• Decree No. 269/2015 Coll. – detailed billing rules (amended by Decree 376/2021 Coll.)
• Act No. 406/2000 Coll. – on energy management
• Decree No. 194/2007 Coll. – rules for heating and hot water supply

Who performs billing

Billing performed by:

• House owner (for apartment buildings with one owner)
• SVJ (association of unit owners)
• Management company (on the basis of a mandate contract)
• Specialized billing company (ISTA, Techem, Minol, etc.)

Deadlines

• Billing period: usually a calendar year (January 1st – December 31st)
• Delivery of the bill: no later than 4 months after the end of the billing period (i.e. until 4/30)
• Complaints: the service recipient can file objections within the applicable period under Act No. 67/2013, unless a valid arrangement provides otherwise
• Settlement: generally within 4 months of delivery of the bill, subject to the applicable rule and any valid agreement

Principle of heat billing

Two cost components

Total heating costs are divided into two components:

1. Basic component (ZS)

• It is paid according to the floor area of ​​the apartment
• It covers fixed heating costs (heat losses of the building, system maintenance)
• Its percentage is determined by the current decree and the building's approved allocation method

2. Consumption component (SS)

• It is paid according to the actual consumption measured by indicators or meters
• Motivates to save
• It is the corresponding consumption component under the current decree and allocation method

Recommended ratio

Decree 269/2015 Coll. determines:

• Basic and consumption components: use the percentages required by the current decree for this building

If the owner/SVJ does not set the ratio, apply the default prescribed by the current decree; do not copy a 30%/70% split without checking the current rule.

Which ratio to choose?

• Higher basic component (50/50) = smaller differences between apartments, suitable for older houses with worse insulation
• A higher consumption component can increase the incentive to save, but the permitted ratio must be checked under the current decree

Measuring device

Heating cost indicators (ITN/RTN)

What are: Electronic devices attached to radiators that measures the relative consumption of heat in a given room.

Important:

• ITN does not measure absolute consumption in kWh or GJ
• They show proportional "parts" (dimensionless units)
• The values of different types of ITN are not mutually comparable
• The evaluation is carried out by a specialized company

Types:

• Evaporative (older type) – less accurate, cheaper
• Electronic single sensor – measures the temperature of the radiator
• Electronic two-sensor – measures the temperature of the radiator and the surroundings (more accurate)

Residential heat meters (calorimeters)

What are they: Certified measuring devices that measure actual heat consumption in kWh or GJ.

Advantages:

• Direct real measurement of consumption
• More accurate than ITN
• Data directly in energy units

Disadvantages:

• More expensive installation
• They require horizontal heating distribution
• Regular verification at the period prescribed for the exact instrument under the current UNMZ rules

Ratio method vs. direct measurement

The parameter	ITN (Ratio Method)	Calorimeters (direct measurement)
Value type	Proportional parts	kWh or GJ
Accuracy	Lower	Higher
Installation price	Lower	Higher
Suitability	Vertical distributions (risers)	Horizontal distribution
Verification	Replacement after battery life	Follow the current instrument-specific UNMZ period

Correction coefficients

Why are they used

Not all apartments have the same conditions for heating. An apartment on the north side on the top floor needs more energy to reach the same temperature than an apartment in the middle of the house. Correction coefficients compensate for these differences.

Position coefficients

Take into account the position of the apartment in the building:

By floor:

• Ground floor / first floor: coefficient 1.05-1.15 (higher losses to the ground/basement)
• Middle floors: coefficient 1.00 (reference)
• Top floor: coefficient 1.05-1.20 (losses through the roof)

According to orientation:

• North side: coefficient 1.05-1.10
• South side: coefficient 0.95-1.00
• Corner apartment: coefficient 1.05-1.10

Example of coefficients for a block of flats:

Location of the apartment	Coefficient
Ground floor, corner, north	1.20
Ground Floor, Middle, South	1.05
3rd floor, center, south	1.00
3rd floor, corner, north	1.10
Last floor, corner, north	1.25
Last Floor, Middle, South	1.10

Radiator coefficients (KC)

U heating cost indicators, the KC coefficient is used, which takes into account:

• Radiator type and size
• Radiator thermal output
• Connection method

The KC coefficient is determined by the ITN manufacturer or billing company based on the technical documentation of the radiators.

Calculation billing: Step by step

Input data for example

Let's consider an apartment building with the following parameters:

• Total heat costs per year: 450,000 Kč
• ZS/SS ratio: 40% / 60%
• Number of apartments: 12
• Total floor area: 720 m²
• Total sum of corrected parts of ITN: 3,600

Step 1: Division into components

• Basic component (ZS) = 450,000 × 0.40 = 180,000 Kč
• Consumption component (SS) = 450,000 × 0.60 = 270,000 Kč

Step 2: Calculation of the basic component for a specific apartment

Apartment No. 5 has a floor area of 65 m².

ZS for apartment No. 5 = 180,000 × (65 / 720) = 180,000 × 0.0903 = 16,250 Kč

Step 3: Calculation of consumption components

Apartment No. 5 has 320 corrected ITN units measured.

SS for apartment No. 5 = 270,000 × (320 / 3,600) = 270,000 × 0.0889 = 24,000 Kč

Step 4: Total heat costs for apartment No. 5

Total = ZS + SS = 16,250 + 24,000 = 40,250 Kč/year (i.e. approx. 3,354 Kč/month)

Step 5: Check limits

Decree 269/2015 Coll. sets protective limits:

• Adjustment limits: apply the current decree's formula and limits for the building; do not use fixed -20% or +100% thresholds

Illustrative calculation: the example uses an average of 375 Kč/m², but the applicable adjustment calculation and limits must be taken from the current decree and the building's data; do not treat the example's range as a legal threshold.

What if the apartment exceeds the limit?

If the consumption component of the apartment exceeds the upper or lower limit:

1. Apply the correction required by the current decree
2. Recalculate the affected shares using the prescribed method

Special situation

Apartment without deduction (inaccessible apartment)

If the tenant does not allow deduction of ITN:

• Substitute calculation is used according to the decree
• The consumption component is determined using the substitute calculation and multiplier prescribed by the current decree; do not use a fixed 1.6 coefficient
• The tenant thus pays significantly more, which motivates him to make the apartment available

Apartment unoccupied part of the year

• The basic component is paid for the entire period (regardless of occupancy)
• The consumption component corresponds to the measured consumption
• Even in an unoccupied apartment, heating should be kept to a minimum (protection against freezing)

Change of tenant during year

When changing the tenant:

1. An extraordinary reading of the ITN will be carried out on the date of change
2. The costs will be divided proportionally between the old and new tenant
3. The basic component is divided according to the number of days

Apartment without meters

If an apartment does not have metering devices installed:

• The consumption component is determined according to the floor area
• Or a substitute indicator is used (type of radiator, number of cells)

Billing of hot water

Principle

Hot water heating costs are billed similarly:

• Basic and consumption components: allocate hot-water costs using the current decree and the building's approved method; hot-water allocation is separate from space-heating allocation

Difference compared to heat

• Hot water is always measured directly (residential water meters)
• The DHW allocation ratio is not a universal 30%/70% rule; check the current decree and approved method
• The consumption component corresponds to the actual consumption in m³

The most common errors in billing

Error 1: Bad corrections coefficients

The coefficients were not updated after the house was insulated, the windows were replaced or the layout of the apartments was changed. After each such change, the coefficients must be recalculated.

Error 2: Missing readings

Incomplete readings lead to inaccuracies and disputes. Ensure that readings are taken in all apartments during the same period.

Error 3: Outdated ITN

Evaporation indicators or electronic ITNs may show inaccurate readings after the battery life has ended. Regularly renew the measuring technique.

Error 4: Failure to respect the limits

Omission to check the upper and lower limits leads to unfair billing and justified complaints.

Error 5: Incorrectly determined floor area

The floor area must correspond to reality and be in accordance with the owner's statement. Irregularities lead to errors in the basic component.

Complaints and disputes

Right to complain

The recipient of services has the right to submit objections (complaint) within 30 days of receipt of the bill. The service provider must respond to objections within 30 days.

Frequent reasons for complaints

• Incorrect floor areas
• Missing or incorrect correction coefficients
• Non-performed readings
• Mathematical errors in calculation
• Non-respect of legal limits
• Insufficient explanation of the methodology

How to proceed when complaint

As owner/administrator:

1. Accept the complaint in writing
2. Check the calculation and input data
3. Reply in writing within 30 days
4. If the claim is justified, correct the bill
5. If not, justify your procedure with reference to decree

As a tenant/owner of an apartment:

1. Check the floor area and coefficients
2. Compare your consumption with the average house
3. Check the mathematical correctness of the calculation
4. Submit a written complaint within 30 days
5. Request an explanation of the methodology and input data

Legal solution

If the complaint is not resolved:

• Contact the Energy Regulatory Office (ERÚ)
• Use mediation
• As a last resort, file a lawsuit in court

Practical tips for administrators

Transparency

• Publish the billing methodology to everyone to owners/tenants
• Explain the principles at the house meeting
• Provide a detailed breakdown of the calculation, not just the resulting number

Dispute prevention

• Ensure regular calibration and replacement of meters
• Take readings in all apartments at the same time
• Update correction coefficients after building modifications
• Check limits before distribution billing
• Offer consultation to owners who have questions

Digitization

• Use remote readings (radio ITN) - more accurate, without the need to enter the apartment
• Use accounting software - minimizes mathematical errors
• Archive data electronically - easier to find and compare

Summary

Accounting for heat costs is a complex but manageable process. The key to success is:

• Knowledge of legislation - decree 269/2015 Coll. is your main guide
• Correct data – accurate floor areas, current coefficients, full readings
• Limit compliance – check the upper and lower limits of the consumption component
• Transparency – explain the methodology and be open to questions
• Timeliness – comply with legal deadlines for delivery of bills
• Documentation – archive all data and documents just in case complaints

Quality billing is the basis of the satisfaction of owners and tenants. Invest time in setting up the system correctly and you will avoid most disputes.

How Grento will help you

Grento is the most comprehensive Czech real estate management platform that will help you with automatic billing of services, including heat. The system calculates the settlement according to the set rules and generates documents for the tenants. Try Grento for free and see for yourself.

> Czech-law scope and editorial note: Legal, tax, accounting, tenancy, service-charge, condominium, metrology, insurance and data-protection statements in this article refer to the Czech Republic and the rules effective for the relevant date. Figures and examples are illustrative, not legal or tax advice. Verify current rules with the relevant Czech authority or a qualified adviser.

> Service-accounting clarification: Under Czech Act No. 67/2013 Coll., distinguish delivery of the settlement within four months after the accounting period, financial settlement generally within four months after delivery, and the separate 30-day periods for supporting documents or objections under § 8. A statutory per-day penalty under § 13 is conditional; verify the current amount and cap rather than applying a universal figure.

> Metrology and heat clarification: Verification periods depend on the instrument type and current UNMZ rule. Heat allocation uses the current Czech decree and may use a 40%, 50% or 60% basic component according to building energy performance, with possible adjustments; hot-water allocation is separate. Do not treat a 30/70 or ±20% statement as universal.