Frequently asked questions

District heating is the supply of buildings with heating and hot water from centralised systems. Heated water is channelled directly from the producer, usually a central heating plant, to the connected buildings via insulated pipework systems. With the help of a heat exchanger, the heat is transferred to the consumer's heating network in the house transfer station, but the water from the district heating pipe is not transferred.

• Energy efficiency:
  Energy losses can be reduced through centralised generation.
• Flexibility:
  Different heat generation systems can be combined in an ecologically and economically sensible way and utilised as required.
• Climate protection:
  CO₂ emissions can be reduced through the use of renewable energies.
• Space-saving:
  No separate boilers and tank systems are required in the connected buildings. The space required for the new heating system is significantly smaller.
• Reliability:
  No additional costs for maintenance and servicing.
• No noise emission:
  The transfer station emits no noise and is therefore quieter than any other heating system.
• Security of supply:
  Thanks to redundant heat generation systems in the heating centre, sufficient other heat generators are also available in the event of a fault.

The heat generated in the heating centre is transported to the consumers in the form of hot water via a thermally insulated pipe system (primary network). The system is laid in the floor and consists of:

• Flow pipe: Conducts the hot water (approx. 80°C) to the buildings.
• Return pipe: Conducts the cooled water back to the heating centre, where it is reheated. The pipes are well insulated to minimise heat loss in the pipe network.

Each connected building has a heat transfer station that uses the hot water from the district heating network to transfer heat to the building's heating system. This is done via a heat exchanger that is integrated into the heat transfer station. The heat can be used for all heat consumers in the building.

These include:

• Room heating: via radiators or underfloor heating.
• Hot water preparation: for showers, washbasins, etc.

The water from the district heating network does not come into contact with the water in the building's heating circuit. These are two separate systems.

District heating pipelines:

Care is always taken to ensure that the pipe route is blocked as little as possible by obstacles (sealed surfaces, trees, gardens, other supply lines). The pipe route is always the technically best and most economical route and is discussed with the homeowner. If sealed surfaces (paving, asphalt) are unavoidably crossed along the route of the pipe, the surface will be restored.

The insulated house connection pipes are laid in a pipe trench approx. 80 cm wide. In exceptional cases, it may be necessary to increase the trench width for technical reasons. After the pipework has been laid, the trench is professionally backfilled and compacted to prevent subsidence in the ground. The surface is restored in accordance with the contract.

Building entry:

• Primary pipes: These transport the district heating from the supply network into the building.
• Wall penetration: The pipework is inserted through the cellar wall by core drilling.
• Sealing: As with all other supply lines, the building entry is sealed against moisture, pressure and heat loss.
• Location of the building entry: Usually near the boiler room. Also possible in other rooms to optimise the pipe run.
• Accessibility: The entry point should be easily accessible for maintenance and inspections.

An expert from the district heating operator can check the pipe route for possible obstacles (e.g. other supply lines, plants, terraces, sealed surfaces). The pipe routing is always the technically best and most economical route and is agreed with the homeowner

Authorisations:

• When working in the front garden, especially in the case of trees or hedges, it may be necessary to consult the horticultural office.
• In the case of listed buildings, authorisation may need to be obtained from the relevant authority.

Relocation:

• The district heating supply company lays a connection from the main pipe to the house inlet. Trenches are dug in the front garden and the pipes are laid. Once the pipework has been completed, the trench is backfilled and the surface restored.

House connection station:

• A heat transfer station is installed in the building (boiler room), which feeds the district heating into the building's heating system.
• The heat transfer station is connected to the existing heating system and put into operation.

Hydraulic balancing is a measure that is carried out in heating systems to ensure that heat is distributed evenly and efficiently to all radiators or consumers.

Without hydronic balancing, more heating water often flows through radiators close to the heating circuit distribution and less through radiators further away.

This leads to:

• Uneven heat distribution (some rooms are too warm, others too cold).
• Higher energy consumption as the heating is inefficient.

Hydraulic balancing - Advantages:

• Energy saving: Balancing reduces the energy consumption of the heating system by up to 15 %.
• Even heat: All rooms reach the desired temperature.
• Cost reduction: Lower energy consumption reduces heating costs.
• Climate protection: Lower energy consumption also means lower CO₂ emissions.

Listed buildings require special consideration in order to preserve the character and substance of the monument. The most important aspect here is coordination with the monument protection authority:

Any structural alteration to a listed building, including the installation of a district heating connection, requires the approval of the relevant monument protection authority. The connection must be checked on a case-by-case basis, but is certainly possible.

If you want to continue using your existing system in the short term, but are planning to purchase a new heating system in the medium term, we recommend our FLEX connection. In this case, the district heating network pipes are laid up to approx. 1 metre behind your property boundary. You continue to use your existing system and only pay the annual basic fee until you are fully connected to the heating network. The full connection with all conversion work on your heating system takes place after a maximum of 2 years after the contract is concluded.

In this case, you can burn the fuel with our FLEX connection within a maximum of 2 years, or have the fuel pumped out by an independently commissioned specialist company before construction of the standard house connection begins. A certified specialised company can be arranged by MaxSolar.

• Pumping out oil residues: The oil tank is emptied and the remaining heating oil is pumped out and disposed of.
• Cleaning the tank: The tank is cleaned to professionally remove residues such as sludge, water or oil.
• Dismantling / decommissioning: 
  - Boiler: The boiler is removed, dismantled into individual parts and recycled or disposed of.
  - Cellar tanks can be cut up on site to facilitate dismantling and removal through existing doors.
  - Underground tanks are emptied, cleaned and backfilled.
• Environmentally friendly disposal
• Verification: The specialised company issues a certificate of proper disposal. This proof of disposal is decisive for the receipt of subsidies.

The customer's heating circuit distribution is converted within the scope of the contractual provisions. Existing systems such as additional buffer storage tanks, solar thermal systems or similar that can continue to be operated sensibly according to technical and economic criteria are taken into account. The services and system components included in the flat-rate contract are described in the annex to the contract. The conversion measures are planned in individual consultation with the homeowner and are carried out by regional heating engineers.

No, the state subsidy for connecting to a district heating network is only available if the old oil or gas heating system is actually removed and disposed of properly.

Existing systems such as solar thermal systems or photovoltaic systems with heating rods can normally be integrated into the new district heating system - this will be checked by our experts on a case-by-case basis. Wood-burning stoves can continue to be operated as usual.

MaxSolar GmbH is the general contractor and prepares a complete offer for the primary and secondary side. All conversion work is coordinated and carried out by regional companies.

The district heating network is built in sections. After signing the contract, you will receive a rough connection date, which depends on the various construction phases in the heating network in which your connection is located. We will inform you about the upcoming construction work in your street and in your house in good time before the start of construction of your construction section. For your district heating house connection, the pipework connection between the street and the house is created first. To do this, the pipeline is laid up to behind the house inlet and sealed with ball valves. As soon as the district heating route in the respective construction section is completed, the construction section can be put into operation to such an extent that hot water is available at all ball valves. As soon as this is the case, the conversion work on your heating system can begin. The conversion work on your heating system usually takes between 1 and 3 days and is closely timed to minimise downtime. If necessary, a temporary heating system can be used.

The flow temperature in the district heating network is approx. 80° C, which means that all buildings can be supplied with a sufficiently high temperature. The return temperature in the district heating network is approx. 40° C.

No generalised statement can be made here. Please contact your tax advisor.

The subsidy is paid out after the homeowner has submitted all the necessary documents. This includes documents and data on the district heating network as well as proof of heating replacement and hydraulic balancing. MaxSolar GmbH provides documents and supports you in the best possible way when applying for the subsidy. The duration of the payment process varies greatly and cannot be generalised at the moment.