If you don’t know the type of wall, choose: - “Uninsulated walls (with gap)” – if the construction was built after 1940 and does not have external wall insulation - “Lightly insulated walls (with gap)” – if the construction was built after 1970 and does not have external wall insulation - “Solid walls, without insulation” – if the construction was built before 1940 and does not have external wall insulation. -- “Insulated walls” – if the building has external wall insulation

The roof of your building can be uninsulated, lightly insulated or highly insulated, according to the thickness of the insulation applied: - An uninsulated roof refers to a roof that has not been insulated but only weatherproofed - A lightly insulated roof refers to a roof that has been insulated with material of up to 5cm in thickness - A highly insulated roof refers to a roof insulated with material with a thickness greater than 5cm

Indicate the most common type of window in your building. - “Single-glazed” windows have a single pane of glass and are common in buildings built or restructured before the 1990s - “Double-glazed” windows have two panes of glass separated by an air chamber which limits the heat exchange with the outside environment and are common in apartments built or restructured between 1990 and 2010 - Windows with “low-emissivity glass” are equipped with features to reduce the temperature exchange with the outside environment (e.g. the application of thin layers of metal that reflect heat). This type of window is most common in apartments built or restructured after 2010.

If both centralised and independent heating systems are present in your building, indicate the type that is most common in the residential units.

The heating systems run on: - “Methane gas” – this is common in independent and central heating systems built or restructured after 2000 - “Diesel fuel” – this is most frequent in central heating systems where the boiler has not been replaced in recent years - “LPG (tank gas)” – this is a solution used when the system is not connected to the mains gas grid - “Electricity” – systems running on electricity have heat pumps instead of a conventional boiler.

The heating system can be equipped with: - A “conventional boiler” – conventional boilers do not recover the heat from latent waste gases and were commonly installed before 2000. - A “condensing boiler” – condensing technology recovers latent heat from waste gases. These were commonly installed when boilers were replaced after 2000. - A “heat pump” – heat pump technology runs on electricity and generally has equipment that can provide either cold or hot air (fan coil). They are commonly found in residential buildings constructed after 2010.

The system producing domestic hot water can be: - “Independent” – when each residential unit has its own water heater - “Central” – when the hot water is provided by a centralised system used by all the residents in the condominium building. If both types of hot water production are present in the building, indicate which system is most commonly used by the residential units.

This is the cost incurred by your apartment building for heating and hot water production. If there are independent systems present, then this expense includes the entirety of the costs incurred by the individual residential units.

This is the cost incurred by your apartment building for electricity use in common areas. This is generally for: lighting in common areas, elevators and, where present, the heating systems using heat pumps.