Roof Overhang Sizing for Solar Shading: Solar Altitude Angle Equations & Latitude Ratios
An empirical technical engineering guide covering passive solar roof overhang calculation. Detailed equipment sizing formulas, ...
Technical Topic Hub
Passive Building
Architectural principles, thermal mass sizing, building envelope insulation, passive solar orientation, and geothermal heat pump engineering for ultra-efficient homes.
Published Technical Guides (25)
Thermal Mass Sizing: Volumetric Heat Capacity of Concrete, Masonry & Trombe Walls
An empirical technical engineering guide covering thermal mass sizing ratio passive solar. Detailed equipment sizing formulas, ...
Triple-Pane vs. Double-Pane Low-E Windows: U-Factor, SHGC, Condensation & Payback
An empirical technical engineering guide covering triple pane vs double pane windows cost. Detailed equipment sizing formulas, ...
Continuous Exterior Insulation (ci): Eliminating Thermal Bridging in 2x6 Framing
An empirical technical engineering guide covering continuous exterior insulation 2x6 framing. Detailed equipment sizing formula...
Cold-Climate Air-Source Heat Pumps: Low-Ambient Heating at -15°F & Inverter Compressors
An empirical technical engineering guide covering cold climate heat pump -15 degrees. Detailed equipment sizing formulas, 2026 ...
Blower Door Testing & Air Sealing: Target ACH50 Thresholds, Smoke Pencils & AeroBarrier
An empirical technical engineering guide covering blower door test ach50 calculation. Detailed equipment sizing formulas, 2026 ...
HRV vs. ERV Mechanical Ventilation: Sensible vs. Latent Heat Recovery Across US Climates
An empirical technical engineering guide covering hrv vs erv for tight house. Detailed equipment sizing formulas, 2026 installe...
Insulation Material Showdown: Closed-Cell Foam vs. Dense-Pack Cellulose vs. Rockwool
An empirical technical engineering guide covering spray foam vs mineral wool vs cellulose. Detailed equipment sizing formulas, ...
Earth-Sheltered & Bermed Homes: Structural Soil Loads, Waterproofing & Thermal Stability
An empirical technical engineering guide covering earth sheltered home construction cost. Detailed equipment sizing formulas, 2...
Solar Chimneys & Thermal Siphons: Zero-Energy Cooling Using the Buoyancy Stack Effect
An empirical technical engineering guide covering solar chimney passive cooling design. Detailed equipment sizing formulas, 202...
Manual J Load Calculations: Sizing Heat Pumps Without Contractor Oversizing Rules of Thumb
An empirical technical engineering guide covering manual j load calculation guide. Detailed equipment sizing formulas, 2026 ins...
Straw Bale Construction: Wall R-Values (R-30 to R-45), Lime Plaster & Moisture Sensors
An empirical technical engineering guide covering straw bale house r value. Detailed equipment sizing formulas, 2026 installed ...
Cool Roofs & Radiant Barriers: Solar Reflectance Index (SRI) & Attic Heat Reductions
An empirical technical engineering guide covering solar reflectance index sri cool roof. Detailed equipment sizing formulas, 20...
Hempcrete Building Science: Thermal Inertia, Hydrated Lime Binders & Carbon Sequestration
An empirical technical engineering guide covering hempcrete r value and cost. Detailed equipment sizing formulas, 2026 installe...
Sub-Slab & Frost-Protected Shallow Foundations (FPSF): XPS vs. EPS Compressive Strength
An empirical technical engineering guide covering sub slab insulation r value. Detailed equipment sizing formulas, 2026 install...
Nighttime Radiative & Convective Flushing: Passively Cooling High-Thermal-Mass Homes
An empirical technical engineering guide covering night flush cooling thermal mass. Detailed equipment sizing formulas, 2026 in...
Smart Vapor Retarders: Variable Permeability Membranes (Pro Clima INTELLO & MemBrain)
An empirical technical engineering guide covering smart vapor retarder intello. Detailed equipment sizing formulas, 2026 instal...
Exterior vs. Interior Window Shading: Solar Heat Blockage, Motorized Zip Screens & Shutters
An empirical technical engineering guide covering exterior solar screens for windows. Detailed equipment sizing formulas, 2026 ...
Geothermal Ground Loops: Vertical Boreholes vs. Horizontal Trenches & Slinky Coils
An empirical technical engineering guide covering geothermal vertical vs horizontal loop cost. Detailed equipment sizing formul...
The Net-Zero Energy Roadmap: Load Reduction, Airtightness & Renewable Sizing Order
An empirical technical engineering guide covering net zero home design guide. Detailed equipment sizing formulas, 2026 installe...
Radon Gas Mitigation in Tight Homes: Passive Sub-Slab Venting vs. Active In-Line Fans
An empirical technical engineering guide covering passive radon mitigation system design. Detailed equipment sizing formulas, 2...
Insulated Concrete Forms (ICF) vs. Wood Framing: R-Value, Acoustic STC & Structural Integrity
An empirical technical engineering guide covering icf vs wood framing cost and r value. Detailed equipment sizing formulas, 202...
Unvented Conditioned Attics: Spray Foam Roof Deck Insulation & Dew Point Control
An empirical technical engineering guide covering unvented attic spray foam roof deck. Detailed equipment sizing formulas, 2026...
Home Energy Audits with Infrared FLIR Cameras: Locating Air Infiltration & Insulation Voids
An empirical technical engineering guide covering thermal imaging home energy audit. Detailed equipment sizing formulas, 2026 i...
Light Clay Straw (Lehmwickel) Infill: Natural Non-Toxic Wall Insulation & Thermal Mass
An empirical technical engineering guide covering light clay straw construction slip straw. Detailed equipment sizing formulas,...
VERIFIED 2026 HARDWARE BENCHMARKCross-Referenced with US Lab Testing & National Codes
Passive Building & Envelope Science Benchmarks
Real-world low-ambient COP ratings, blower door ACH50 performance metrics, and continuous exterior insulation R-value per inch.
📊 Cold-Climate Heat Pumps (Tested Heating Output @ -15°F / -26°C)
| System Model | Rated Nominal Capacity | Heating Capacity @ 5°F | Heating Capacity @ -15°F | COP @ 5°F | SEER2 / HSPF2 | 2026 Equipment Cost |
|---|---|---|---|---|---|---|
| Mitsubishi Hyper-Heating (H2i) 24k | 24,000 BTU/h | 24,000 BTU (100% capacity) | 19,200 BTU (80% capacity) | 2.15 | 21.5 / 10.5 | $4,150 |
| Daikin Aurora 24k Multi-Zone | 24,000 BTU/h | 21,600 BTU (90% capacity) | 16,800 BTU (70% capacity) | 1.95 | 20.0 / 10.2 | $3,600 |
| Fujitsu Halcyon XLTH 24k | 24,000 BTU/h | 24,000 BTU (100% capacity) | 18,500 BTU (77% capacity) | 2.08 | 21.0 / 10.4 | $3,890 |
| Carrier Infinity with Greenspeed 3-Ton | 36,000 BTU/h | 32,000 BTU (88% capacity) | 24,000 BTU (67% capacity) | 2.20 | 22.0 / 11.0 | $6,400 |
📊 Continuous Exterior Insulation Materials Comparison (Thermal Bridging Mitigation)
| Insulation Material | R-Value per Inch | Vapor Permeance (Perms) | Compressive Strength | Embodied Carbon | Cost per Sq Ft (2") | Fire Rating |
|---|---|---|---|---|---|---|
| Rockwool Comfortboard 80 (Stone Wool) | R-4.2 / inch | 30.0 (Vapor Open / Breathable) | 800 psf | Low / Mineral based | $1.85 / sq ft | Class A (Non-combustible) |
| Expanded Polystyrene (EPS Type II) | R-4.0 / inch | 2.0 - 5.0 (Semi-Permeable) | 2,160 psf | Moderate | $1.10 / sq ft | Requires Ignition Barrier |
| Extruded Polystyrene (XPS Type IV) | R-5.0 / inch | 1.0 (Vapor Retarder) | 3,600 psf | High (HFO Blowing Agents) | $1.65 / sq ft | Requires Thermal Barrier |
| Polyisocyanurate (Foil-Faced Polyiso) | R-6.0 - 6.5 / inch | 0.05 (Vapor Barrier) | 2,880 psf | Moderate-High | $2.15 / sq ft | Class A / Foil protected |
Methodology Notice: Data synthesized from manufacturer submittals, UL test certifications, NREL System Advisor Model (SAM), and field installation audits conducted across US climate zones. Prices reflect Q1 2026 wholesale/retail benchmarks.