Passivhaus is the world's leading standard for energy-efficient buildings, originating in Germany. It reduces heating demand by up to 90% compared to typical buildings through super-insulation, airtightness, thermal bridge-free design, high-performance windows, and mechanical ventilation with heat recovery (MVHR).

What are the Passivhaus criteria?

Space heating demand: max 15 kWh/m2.a. Space cooling demand: max 15 kWh/m2.a. Primary Energy Renewable (PER): max 60 kWh/m2.a for Classic (45 for Plus, 30 for Premium). Airtightness: max 0.6 air changes per hour at 50Pa (n50). Peak heating load: max 10 W/m2. All must be met for certification.

How is airtightness measured?

Airtightness is tested using a blower door test (pressure test) at 50 Pascals. The Passivhaus limit is 0.6 ACH@50Pa (air changes per hour at 50 Pascals). This is extremely airtight - typical UK new builds achieve 3-5 ACH@50Pa. Achieving 0.6 requires careful detailing and quality workmanship.

Do Passivhaus buildings need conventional heating?

Passivhaus buildings need very little heating - the post-heating air from the MVHR system can often provide enough warmth. A small backup heater (electric panel or heat pump) may be needed for the coldest days. Radiator systems are usually unnecessary.

How much more does Passivhaus cost?

A Passivhaus typically costs 8-15% more than a standard build. Costs are reducing as the approach becomes mainstream. The premium is offset by dramatically lower energy bills (up to 90% reduction in heating costs), improved comfort, and higher property values.

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Passivhaus Criteria Calculator

Check your design against Passivhaus certification requirements

Treated Floor Area

Annual Space Heating

Airtightness (n50)

Annual Primary Energy

How We Calculate This

Enter your building's treated floor area, annual space heating demand, airtightness test result, primary energy demand, and peak heating load. The calculator checks each value against the Passivhaus certification thresholds and reports pass/fail for each criterion. If renewable generation data is provided, it determines whether Passivhaus Plus classification is achieved.