liminfoPassive House Reference
Free reference guide: Passive House Reference
About Passive House Reference
The Passive House Reference is a searchable quick-reference guide covering all key criteria and technical data needed to design, build, and certify Passive House buildings according to the Passive House Institute (PHI) standard. It covers the five core energy criteria: maximum heating demand of 15 kWh/(m2a) with a 10 W/m2 heating load limit, primary energy demand tiers for Classic (120), Plus (60), and Premium (0) kWh/(m2a), airtightness at n50 less than or equal to 0.6 ACH measured by blower door test per EN 13829, summer overheating frequency below 10% above 25 degrees Celsius, and cooling demand limits with dehumidification allowances for warm climates.
The reference provides detailed U-value targets for every building envelope component: external walls (0.10-0.15 W/(m2K) depending on climate), roofs, ground floors, windows (Uw less than or equal to 0.80 W/(m2K) installed, with component breakdown for glazing Ug, frame Uf, warm-edge spacer Psi-g, and installation Psi), and doors. Ventilation coverage includes HRV heat recovery efficiency requirements (75% minimum for PHI certification, 80-90% recommended), specific fan power limits (SFP less than or equal to 0.45 Wh/m3), duct design velocities and noise criteria, supply/exhaust balancing procedures, and ground heat exchangers for pre-heating/pre-cooling.
The reference also covers thermal bridge-free design principles (Psi less than or equal to 0.01 W/(mK)), junction-specific Psi value targets with PHI-certified components like Isokorb, condensation prevention via surface temperature factor fRsi, PHPP (Passive House Planning Package) worksheets and TFA calculation rules, climate data, PHI certification levels (Classic/Plus/Premium), EnerPHit retrofit criteria with both energy demand and component U-value methods, component certification classes, and construction details for airtight layers, window installation within insulation, and EIFS/ETICS external insulation systems.
Key Features
- PHI energy criteria: 15 kWh/(m2a) heating demand, primary energy tiers (Classic/Plus/Premium), and n50 airtightness targets
- U-value targets for walls, roof, floor, windows (Ug, Uf, Psi-g, Psi-install breakdown), and doors with insulation thickness examples
- HRV heat recovery efficiency (75%+ PHI requirement), SFP limits, airflow rates, duct velocities, and noise criteria per room type
- Thermal bridge-free design: Psi/Chi targets, junction-specific values, fRsi condensation prevention, and PHI-certified components
- PHPP worksheet overview (Areas, U-Values, Windows, Ventilation, Summer, DHW, PER/PE), TFA calculation rules, and climate data
- PHI Classic/Plus/Premium certification tiers and EnerPHit retrofit criteria (energy demand and component methods)
- Airtight layer construction: pencil line rule, material specifications (PE membranes, acrylic/butyl tapes), and blower door test timing
- Window installation within insulation layer with Psi values for timber, concrete, and extension frame details, plus EIFS/ETICS construction
Frequently Asked Questions
What are the core Passive House energy criteria?
The five core criteria are: heating demand no more than 15 kWh/(m2a) with heating load maximum 10 W/m2, primary energy demand (Classic: 120, Plus: 60, Premium: 0 kWh/(m2a) with renewable generation requirements), airtightness n50 no more than 0.6 ACH, summer overheating below 10% annual hours above 25 degrees, and cooling demand no more than 15 kWh/(m2a) with optional 4 kWh/(m2a) dehumidification allowance.
What U-values are required for Passive House windows?
The installed window U-value (Uw) must be 0.80 W/(m2K) or less. This breaks down to: glazing Ug no more than 0.70 W/(m2K) using triple low-e glass, frame Uf no more than 0.80 W/(m2K), warm-edge spacer Psi-g no more than 0.035 W/(mK), and installation Psi no more than 0.04 W/(mK). Typical glazing specification is 4-16Ar-4-16Ar-4 triple glass with argon fill and g-value (SHGC) of 0.50-0.55.
What HRV efficiency is required for Passive House certification?
PHI certification requires a minimum heat recovery efficiency of 75%, though 80-90% is recommended. Specific fan power (SFP) must not exceed 0.45 Wh/m3. Minimum ventilation is 30 m3/h per person, with kitchen exhaust at 60 m3/h, bathroom at 40 m3/h, and WC at 20 m3/h. Duct velocities should be 3-4 m/s for main ducts, 2-3 m/s for branches, and 1-2 m/s at diffusers.
What does thermal bridge-free design mean?
Thermal bridge-free means linear thermal bridges (Psi) and point thermal bridges (Chi) are both 0.01 W/(mK) or W/K or less. Three key principles: continuity (unbroken insulation envelope), penetration avoidance (minimize through-connections), and geometry optimization (reinforce corners). PHI-certified components like Schock Isokorb for balconies, Compacfoam for load-bearing insulation, and Purenit for supports help achieve this.
How does the EnerPHit retrofit standard differ from Passive House?
EnerPHit allows relaxed criteria for existing buildings: Method 1 allows heating demand up to 25 kWh/(m2a) with n50 up to 1.0 ACH. Method 2 specifies component U-values: walls, roof, and floor each at U 0.35 W/(m2K), windows at Uw 1.20 W/(m2K), with airtightness n50 up to 1.0 ACH. Values vary by climate zone.
What is PHPP and what does it calculate?
PHPP (Passive House Planning Package) is the official calculation tool. Key worksheets include: Areas (building areas and volumes with TFA rules), U-Values (assembly thermal transmittance), Windows (specs, orientation, shading), Ventilation (design), Annual Heat Demand, Heating Load, Summer overheating check, DHW (hot water), Electricity, and PER/PE (primary energy). TFA counting rules: living spaces at 100%, utility rooms at 60%, enclosed balconies at 50%.
How should the airtight layer be constructed?
Follow the pencil line rule: the airtight layer must be drawable as one continuous line on section drawings. Place it on the warm (interior) side. Use PE membranes (0.2mm or thicker), acrylic or butyl tapes for joints, and airtight grommets/cuffs for penetrations. Perform the first blower door test immediately after airtight layer completion (while repairs are still possible) and the second at project completion for certification.
What are the Passive House certification levels?
PHI offers three tiers: Classic (heating demand no more than 15 kWh/(m2a), PER no more than 60 kWh/(m2a), n50 no more than 0.6/h), Plus (same heating limit, PER no more than 45 kWh/(m2a), renewable generation of at least 60 kWh/(m2a)), and Premium (same heating limit, PER no more than 30 kWh/(m2a), renewable generation of at least 120 kWh/(m2a)). Component certification classes include window ratings (phA+/phA/phB/phC) and HRV efficiency ratings.