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Duct leakage calculator Calculate the efficiency of your ventilation system using Duct leakage calculator which can be used to map out the financial effects of choosing leaky ventilation duct system compared with an airtight system. Duct leakage calculator is used to calculate the energy losses as a result of these leaks for a standard hospital, a nursing home for the elderly and an office building.

Basic input calculation In the 'Basic input' section, select the building type, enter the floor area and the improvement of the tightness. This input will calculate both the payback period of the added investment and the annual energy saving of this general building based on general values stated by Ingenium, an independent research and energy audit agency.

Detailed input calculation Customize the calculation by adding detailed information from a specific project and press calculate to see and evaluate the result.


Basic input

Building function
Floor area
Improved tightness duct system

Detailed input

Ventilation airflow
Surface area of ducts (supply & exhaust) (supply & exhaust)
Proportion of circular ducts (supply & exhaust)
Number of circular fire dampers (supply & exhaust)
Number of rectangular fire dampers (supply & exhaust)
Average diameter of circular ducts
Average dimension (width or height) of rectangular ducts
Heat recovery
Moisture recovery
Power humidification
Power control fans
Total power of installed fans
Unit price electricity
€/MWh eVAT
Unit price fuel
€/MWh eVAT
Average static pressure drop in duct
Yearly price increase energy
Calculate Reset

Basic output

Cost reduction at exploitation
€/year eVAT
Extra costs for installation
€/year eVAT
Payback time

Detailed output

Energy consumption fans (supply & exhaust)
kWh electricity
Power demand cooling and dehumidification (supply)
kWh electricity
Power demand humidification (supply)
kWh electricity
Total electricity consumption ventilation
kWh electricity
Fuel demand humidification (supply)
kWh fuel
Fuel demand heating ventilation (supply)
kWh fuel
Total fuel consumption ventilation
kWh fuel
Total energy cost ventilation without leakage losses
€/year eVAT

Reduction Energy Costs

Improved tightness €/year eVAT Percent
From ATC6 to ATC5 0.36 10.95
From ATC6 to ATC4 0.53 15.82
From ATC6 to ATC3 0.58 17.44
From ATC6 to ATC2 0.6 17.98
From ATC6 to ATC1 0.61 18.17
From ATC5 to ATC4 0.16 5.47
From ATC5 to ATC3 0.22 7.29
From ATC5 to ATC2 0.23 7.9
From ATC5 to ATC1 0.24 8.11
From ATC4 to ATC3 0.05 1.93
From ATC4 to ATC2 0.07 2.57
From ATC4 to ATC1 0.08 2.79
From ATC3 to ATC2 0.02 0.66
From ATC3 to ATC1 0.02 0.88
From ATC2 to ATC1 0.01 0.23

Leakage loss calculations

Class Ducts
Fire Dampers
Air Flow
€/year eVAT
ATC6 1 0 5 3 122
ATC5 0 0 5 3 109
ATC4 0 0 4 3 103
ATC3 0 0 4 3 101
ATC2 0 0 4 3 100
ATC1 0 0 4 3 100

Reduction energy cost (Euro/year)

Reduction energy cost (percent)

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