> For the complete documentation index, see [llms.txt](https://help.immodio.app/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.immodio.app/en/anleitung/betriebskostenabrechnungen/heiz-und-warmwasserverbrauch/stammdaten-im-objekt.md).
# Master data in the property
So that Immodio can prepare the heating and hot water statement correctly, the technical master data of the heating system has to be maintained in the property. These details determine which cost types, consumption values and meter readings are relevant for the statement.
**The most important details are:**
* the energy source for the heating
* the energy source for the hot water supply
* whether there is central heating
* the flow temperature of the central heating
* whether there is a gas or oil tank
* the split of operating costs by floor area and consumption
***
### Energy source for the heating
The **energy source for the heating** states which energy is used to run the property's space heating.
Typical energy sources are, for example:
| Energy source | Example |
| ---------------- | ---------------------------------------- |
| Heating oil | central oil heating |
| Natural gas | central gas heating |
| LPG | gas tank on the property |
| District heating | connection to a district heating network |
| Electricity | electric heating or heat pump |
| Pellets / wood | biomass heating |
{% hint style="info" %}
This detail is important because it determines which costs and consumption values are used in the heating cost statement.
{% endhint %}
With network-supplied energy sources such as natural gas, district heating or electricity, consumption is usually determined from supplier invoices or main meter readings. With storable fuels such as heating oil, LPG or pellets, you also have to take into account how much fuel was still in stock at the beginning and at the end of the settlement period. You can find more information on storable fuels [**here**](#gas-or-oil-tank).
***
### Energy source for the hot water supply
The **energy source for the hot water supply** states which energy is used to produce the domestic hot water.
In many buildings the energy source for heating and hot water is identical, so that the central heating system produces both space heat and hot water.
| Heating | Hot water | Example |
| ---------------- | ---------------- | ----------------------------------------------------- |
| Heating oil | Heating oil | central oil heating with a hot water cylinder |
| Gas | Gas | central gas heating with central hot water production |
| District heating | District heating | district heating for heating and hot water |
| Heat pump | Heat pump | a central heat pump for both |
**There can also be differing cases:**
| Heating | Hot water | Example |
| ----------- | --------------------------- | --------------------------------------------------------------------------------- |
| Gas | Electricity | central heating, hot water produced locally by instantaneous heaters in the units |
| Heating oil | Solar thermal + heating oil | hot water is partly supported by solar energy |
***
### Central heating
The **Central heating** option has to be enabled where a shared heating system supplies the entire property with heat.
**Typical examples:**
| System | Central heating? |
| ------------------------------------------------------ | ------------------------- |
| one boiler in the cellar supplies all apartments | yes |
| a district heating connection supplies the building | yes |
| a central heat pump supplies all units | yes |
| every apartment has its own gas boiler | no |
| every apartment has its own electric heaters | no |
| hot water from instantaneous heaters in each apartment | not central for hot water |
Central heating affects the statement:
With central heating the total costs are first recorded at property level. They are then allocated to the individual units using the existing meters, consumption values and allocation keys.
***
### Flow temperature of the central heating
Where there is central heating, the **flow temperature of the central heating** can be maintained.
{% hint style="info" %}
The flow temperature is the temperature of the heating water sent from the heating system into the heating circuit.
{% endhint %}
To do so, first select the "Central heating" tag under "Energy-related features".
The input field for the flow temperature is then shown to you.
Typical guideline values:
| Heating system | typical flow temperature |
| --------------------------------------- | ------------------------ |
| older radiator system | approx. 60–75 °C |
| modern radiator system | approx. 45–60 °C |
| underfloor heating | approx. 30–45 °C |
| heat pump with a low-temperature system | often approx. 30–45 °C |
{% hint style="info" %}
Important: Stating a flow temperature is optional and generally not strictly necessary for the heating and hot water cost statement. It is only needed where you do not have an exact meter reading for the total consumption used to heat the hot water and have to calculate it using the formula.
{% endhint %}
***
### Gas or oil tank
The **Gas/oil tank** option should be enabled where the energy source is stored in or at the property and topped up by deliveries.
| Energy source | Tank / store present? |
| ------------- | --------------------- |
| Heating oil | yes, an oil tank |
| LPG | yes, a gas tank |
| Pellets | yes, a pellet store |
| Wood | yes, stock possible |
{% hint style="info" %}
This detail is very important for the statement, because with storable fuels a distinction has to be made between the **quantity purchased** and the **quantity consumed**.
{% endhint %}
#### Effects of the gas or oil tank – quantity and quantity consumed
With heating oil, LPG or pellets, the quantity purchased in the billing year does not necessarily correspond to the quantity actually consumed in the same period. The reason is that the central tank stock is usually neither completely empty nor completely full at the beginning and end of the settlement period.
If the tank is filled at the end of the year shortly before the settlement date, that delivery has been paid for but has not yet been fully consumed. Conversely, fuel purchased in the previous year can be consumed during the current year. The opening stock therefore also has to be taken into account.
**The formula is:**
```
opening stock + deliveries during the settlement period - closing stock = quantity consumed
```
For the heating cost statement it is generally the **quantity consumed** that matters, not just the quantity purchased. With heating oil, consumption is usually determined from the opening stock plus deliveries minus the closing stock.
When you determine the total consumption in step **"5. Heating and hot water consumption"**, you can accordingly enter the **quantity of the energy source consumed** and the **cost of the quantity of the energy source consumed**.
***
### Splitting operating costs by floor area and consumption
The **Heating Costs Ordinance** applies to heating and hot water costs. It generally requires consumption-based billing. This means heating and hot water costs may not normally be allocated entirely by square metres.
The Heating Costs Ordinance provides that part of the costs is allocated by consumption and part by floor area. For heating costs and hot water costs the consumption-based share is generally between **50% and 70%**. The remaining share is allocated by floor area.
You can set the split you want in the property in the **"Billing"** tab. You can find more information on correctly splitting operating costs by floor area and consumption, and on the options for setting this individually for each property in Immodio, [**here**](/en/anleitung/immobilien/objekt/abrechnung-objekt.md).
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