Connection to District Heating

Connecting to a district heating network — an existing heat source (CHP, waste heat, biomass, geothermal) is used and no on-site boiler is needed.

How does connecting to district heating work?

With district heating, heat is not generated in the building but in a central heating plant or in combined heat and power (CHP) plants, from industrial waste heat, biomass or geothermal energy. Hot water reaches the building through an insulated pipe network. There, a compact substation replaces the boiler: a plate heat exchanger transfers the heat to the building's internal heating circuit, and a calibrated heat meter records the energy drawn. Boiler, chimney, fuel storage and maintenance of the heat generator are no longer needed. The CO2 balance depends on the energy mix of the respective network, which in Austria is increasingly fed from renewable sources and waste heat.

Which buildings are suitable for a district heating connection?

A prerequisite is a district heating network within reach – connection pipes under 20 m are typically economical – and the network operator's willingness to connect. Typical buildings are apartment buildings, office buildings and public buildings in urban areas. Buildings with high flow temperatures are also suitable, as district heating networks usually supply 70 to 90 °C; no refurbishment of the heating surfaces is needed. Before deciding, the district heating tariff (standing charge, unit price, connection fee) and the CO2 factor of the specific network should be requested from the operator. If no network is within reach or the terms are unfavourable compared with alternatives, the measure is ruled out.

What does a district heating connection actually deliver?

Final energy falls by 10 to 20 % because boiler losses in the building are eliminated; the substation operates at an efficiency of around 98 %. The main effect is on emissions: 50 to 95 % less CO2, depending on the network mix. An apartment building with 130,000 kWh of useful heat saves around 30,000 kWh of final energy and about 21.4 t of CO2 per year. The investment for connection and substation is 8,000 to 25,000 € for a detached house and 15,000 to 50,000 € for an apartment building, plus the network operator's connection fee. Over a 25-year service life, payback is 10 to 20 years depending on tariff and subsidies.

Energy carrier

Erdgas, Heizöl → Fernwärme

Savings potential

10-20 % Endenergie (Wegfall Kesselverluste), 50-95 % CO2 je nach FW-Mix

Worked example

An apartment building with 1,200 m² of usable floor area has an annual useful heat demand of 130,000 kWh for heating and hot water. The previous gas boiler operates at an efficiency of 0.80 and requires 162,500 kWh of natural gas per year. After connection to the district heating network, the substation transfers the heat at an efficiency of 0.98, so only 132,650 kWh of district heat is drawn. The final energy saving is 130,000 × (1/0.80 − 1/0.98) = 130,000 × (1.25 − 1.02) = 29,900 kWh/a. For the CO2 balance, 162,500 kWh × 0.201 kg/kWh for natural gas is compared with 132,650 kWh × 0.085 kg/kWh for the Austrian district heating average: 32,663 kg − 11,275 kg = 21,387 kg CO2/a. The building therefore saves around 30,000 kWh of final energy and about 21.4 t of CO2 per year.

Investment & payback

Anschluss + Übergabestation: 8.000-25.000 € (EFH), 15.000-50.000 € (MFH); zzgl. Anschlussgebühr Netzbetreiber · Service life: 25 a · Payback: 10-20 (abhängig von FW-Tarif und Förderung) a

Applicability

Requirements

Exclusion criteria

Typical buildings

Frequently asked questions

How much does a district heating connection cost?

A district heating connection including substation costs 8,000 to 25,000 € for a detached house and 15,000 to 50,000 € for an apartment building. On top of this comes the network operator's one-off connection fee, which varies considerably depending on the network and connected load. The substation has a service life of around 25 years. Payback is 10 to 20 years depending on district heating tariff and subsidies.

Is district heating really more climate-friendly than gas?

District heating is considerably more climate-friendly than natural gas in most Austrian networks. The Austrian average is around 0.085 kg CO2/kWh compared with 0.201 kg CO2/kWh for natural gas. However, the range extends from 0.02 kg/kWh for biomass CHP to 0.25 kg/kWh in old fossil-fuel networks. The specific emission factor should therefore be requested from the network operator before assessing the CO2 saving.

Do you still need your own boiler with district heating?

No, with district heating the building's own boiler is eliminated entirely. Only a substation with plate heat exchanger, controls and calibrated heat meter is installed in the building. Chimney, fuel storage, tank and annual boiler servicing are no longer required. This saves space in the plant room and ongoing maintenance costs. The building's internal distribution with pumps and radiators remains unchanged.

How far can the building be from the district heating network?

District heating connections are typically economical with connection pipes under 20 m in length. Longer pipes significantly increase construction costs and heat losses. Whether a connection is possible is decided by the network operator based on network capacity, pipe routing and expansion planning. Many operators publish expansion areas and priority zones in which connections are actively offered.

Which standards apply to district heating substations in Austria?

In Austria, ÖNORM EN 1434 for heat meters and ÖNORM H 5195-1 for heating water requirements apply to district heating substations. The heat meter in the substation must be calibrated, as it forms the basis for billing. Savings are assessed according to the method in the Austrian Energy Efficiency Guidelines Regulation 2016. Technical connection conditions are set by the respective network operator.

Related measures

Standards & sources

Metering points in the EDM Toolbox

Übergabestation hat fast immer einen integrierten geeichten Wärmemengenzähler mit M-Bus oder Modbus-Schnittstelle. Direkter Anschluss an LineMetrics Gateway. Perfekt für Submetering pro Wohnung/Mieteinheit kombiniert mit weiteren Subzählern.

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