Certified Passive House Designer / Consultant cheat sheet
Certified Passive House Designer / Consultant · Keep the key ideas within reach.
Passive House principles, certification criteria and the PHPP
Heating demand ≤ 15 kWh/(m²·a) OR heating load ≤ 10 W/m², using the PHPP calculation method.
Primary energy demand ≤ 60 kWh/(m²·a) (renewable primary energy factor ≤ 60 kWh/(m²·a) for PER).
Airtightness n50 ≤ 0.6 h⁻¹ (pressurization test).
Thermal comfort: operative temperature ≤ 25 °C for ≤ 10% of hours in summer (PHPP verification).
PHPP uses a monthly energy balance method with specific boundary conditions (e.g., internal temperature 20 °C, internal heat gains 2.1 W/m²).
Certification requires verified documentation: PHPP, construction drawings, airtightness test report, and commissioning report.
Passive House classes: Classic (15 kWh/m²a), Plus (renewable energy generation), Premium (even more generation).
The 3-liter house corresponds to ~30 kWh/(m²·a) heating demand; Passive House is ~10% of typical existing building demand.
Building envelope: thermal insulation, thermal bridges, airtightness and construction details
U-value formula: U = 1 / (Rsi + Σ(d/λ) + Rse), where d is layer thickness (m) and λ is thermal conductivity (W/mK).
Thermal bridge penalty: ΔU = ψ · l / A, where ψ is linear thermal transmittance (W/mK), l is length, A is area.
Airtightness layer must be continuous; typical penetration: cables, pipes, windows, doors. Use airtight gaskets and membranes.
n50 = V̇50 / V, where V̇50 is air volume flow at 50 Pa pressure difference, V is building volume.
Allowable thermal bridge ψ values: ≤ 0.01 W/mK for passive house certification (or include in PHPP).
Insulation thickness for U ≤ 0.15 W/m²K: ~20–30 cm for λ = 0.035–0.040 W/mK.
Avoid thermal bridges: wrap insulation continuously around corners, use thermal break elements (e.g., Isokorb) for balconies.
Construction details: windows installed in insulation layer, airtight connection to wall, use of pre-compressed joint tapes.
Windows, doors and solar control: glazing, frames, installation and shading
Window U-value: Uw = (Ag·Ug + Af·Uf + lg·ψg) / (Ag + Af), where Ag is glazing area, Af is frame area, lg is perimeter length.
Triple glazing with Ug ≤ 0.8 W/m²K, frame Uf ≤ 1.0 W/m²K, ψg ≤ 0.04 W/mK for Passive House certification.
Solar heat gain coefficient (SHGC, g-value) should be high for passive solar gain in heating season, low for cooling.
Installation: windows should be mounted in the insulation layer, with airtight connection and thermal break at frame.
Shading: external shading coefficient (e.g., roller blinds, louvers) reduces solar gains; use PHPP to calculate summer overheating risk.
Doors: U-value ≤ 0.8 W/m²K for opaque doors; glazed doors follow window criteria.
Window orientation: south-facing windows for passive solar gain; east/west for morning/afternoon sun; north for diffuse light.
Use of low-e coatings and argon/krypton gas fill to reduce U-value and control SHGC.
Ventilation and indoor air quality: ventilation concepts, heat recovery, duct design and summer comfort
Minimum ventilation rate: 0.3–0.5 air changes per hour (ACH) based on occupancy; PHPP uses 0.3 ACH.
Heat recovery efficiency ≥ 75% (PHI certified) for Passive House; HRV (heat recovery ventilation) with counterflow heat exchanger.
Duct design: keep pressure drops low (< 100 Pa), use smooth ducts, avoid sharp bends, size for low air velocity (≤ 3 m/s).
Summer comfort: avoid overheating via shading, night ventilation, and high thermal mass; PHPP checks hours above 25 °C.
Ventilation system must be balanced; supply and extract air flows matched to avoid pressure differences.
Use of demand-controlled ventilation (DCV) based on CO2 or humidity sensors.
Filtration: F7 or better for supply air to protect heat exchanger and indoor air quality.
Commissioning: measure air flows at each terminal, adjust dampers, verify heat recovery efficiency.
Heating, cooling, domestic hot water and renewables: load calculation, distribution and generation
Heating load calculation: PHPP uses monthly method; peak load ≤ 10 W/m² for Passive House.
Domestic hot water (DHW) demand: typically 30–60 L/person/day at 60 °C; use solar thermal or heat pump for generation.
Distribution losses: insulate pipes, keep DHW circulation loops short, use decentralized systems (e.g., fresh water stations).
Heat generation: air-to-air heat pump (COP ≥ 3.5), ground-source heat pump, or district heating with low primary energy factor.
Renewables: solar thermal for DHW, PV for electricity; PHPP calculates primary energy demand including renewable generation.
Cooling: passive cooling first (shading, night ventilation), then active cooling with high efficiency (EER ≥ 3.5).
Heating distribution: low-temperature systems (e.g., floor heating, radiators sized for 35 °C flow temperature).
Use of buffer tanks for DHW and heating to improve efficiency of heat pumps.
Energy balance, PHPP calculations and verification: heating demand, primary energy, summertime and economics
Heating demand formula (monthly method): QH = QL + QV + QS + QI, where QL is transmission losses, QV ventilation losses, QS solar gains, QI internal gains.
Primary energy (PE) = Σ (final energy × PE factor); PE factor for electricity from grid ~1.8–2.4, for renewables ~0.0–0.7.
PHPP verification: heating demand ≤ 15 kWh/m²a, primary energy ≤ 60 kWh/m²a, airtightness ≤ 0.6 h⁻¹.
Summertime comfort: PHPP checks frequency of overheating (operative temperature > 25 °C) ≤ 10% of hours.
Economics: calculate life-cycle cost, consider subsidies, and compare with conventional building; Passive House often has lower total cost of ownership.
PHPP uses specific climate data; results may vary with location. Use local climate data for accurate verification.
Energy balance includes internal heat gains (2.1 W/m²), solar gains through windows, and thermal bridges.
Verification requires independent quality assurance: check PHPP inputs, construction documents, and on-site inspections.
Quality assurance, construction supervision, commissioning and certification process
Quality assurance: independent PHI-certified verifier checks PHPP, drawings, and construction details.
Construction supervision: on-site inspections at key stages (airtightness layer, insulation, window installation, ventilation).
Commissioning: measure airtightness (n50 test), balance ventilation, test heating system, and verify DHW.
Certification process: submit PHPP, drawings, airtightness test report, and commissioning report to PHI or accredited certifier.
Documentation: as-built drawings, product data sheets, and test reports must be provided.
Airtightness test: performed by trained technician, report includes n50 value and leakage locations.
Ventilation commissioning: measure air flows at each terminal, adjust to design values, verify heat recovery efficiency.
Certification is valid for 5 years; re-certification may require updated documentation.