PASSIVE HOUSES IN TEXAS Shelly Pottorf, AIA, CPHC, LEED AP Principal, Architend Founder, Passive House Houston Co-Chair, AIA Houston Committee on the Environment
What is Passive House? A non prescriptive standard and a proven methodology......
......for exponentially smarter building
What is Passive House?
• a formidable set of skills for optimizing cost/benefit decision-making for a design team
What is Passive House? An energy standard that is the most ambitious in the world. Old
New
47.5
•4.75 kBTU/s.f. yr. max. heating demand •4.75 kBTU/s.f. yr. max. cooling demand •0.6 ACH50 max. air leakage •38 kBTU/s.f. max. Primary Energy demand
47.5 7.0 200
from alan gibsons presentation
What is Passive House? (Home Energy Rating System)
Passive House buildings use 7080% less energy than conventional buildings. (90% less energy for space conditioning)
EPA Energy Star V3 Department of Energy Challenge Home
Passive House
Net Zero feasible! Living Building Challenge
Source: Environmental Building News
What is Passive House? TAKING IT MAINSTREAM
Main Principles of Passive Building
Main Principles of Passive Building
BALANCE FOR HEATING SEASON
GAINS
•Solar heat gain through windows •Internal gains -people & pets -lights -equipment -cooking -showering/bathing
≈
LOSSES
•Losses through envelope -conduction -air exfiltration •Losses through ventilation system
Main Principles of Passive Building
BALANCE FOR COOLING SEASON
LOSSES
•Losses through envelope -thermal mass
≈
GAINS
•Solar heat gain through windows •Internal gains (same as heating season)
•Gains through envelope -conduction -air infiltration -radiation •Gains through ventilation system
Main Principles of Passive Building
Ingredients
Climate Specific Design
Optimize Thermal Envelope
AirTightness
Thermal Bridge Free
Energy Minimal Recovery Mechanical Ventilation System
Climate Specific Design Tools of the CPHC: x
• Software uses Detailed Annual Local Weather Data
• Orientation and Size of Windows/Shading Fine-Tuned to Influence Solar Gain Performance
• Adjust knobs to balance the energy
coming and going from the envelope for specific local climate
R-Values
SHGC
U-Value
ERV Eff.
Climate Specific Design COOLING SEASON LOADS
BSC charts on latent loads
Dehumidification and Cooling Loads from Ventilation Air; ASHRAE Journal, Nov. 1997
Design Tools Energy Model 1 - The “Passive House Planning Package” (PHPP) •Energy balance software •Optimize the envelope from the beginning •Establish optimal window count, shading, and insulations levels
•THERM for thermal bridge calculations •WUFI for moisture/condensation risk prediction •ISSUES: hot humid climate cooling loads, humidity
Design Energy Model 2 - WUFI Passive •Great for cost/benefit analysis, fixes shortcomings of model 1 •Explains coupled heat and moisture transfer in building components •Sketch up import
Hot & Humid Passive House LeBois House, Lafayette, LA Architect: Saft Architects •First Certified Passive House in Hot & Humid •1,200 SF new construction •floor system: unconditioned crawl space- CMU wall w/ R-21 continuous rigid insulation •wall system: 2x6 advanced wood framing w/ rainscreen facade to exterior •insulation includes open cell spray foam in cavity + continuous polyiso on exterior -R-28 Walls -R-55 Roof •energy recovery ventilation •ductless mini-split •added dehumidifier
Hot & Humid Passive House LeBois House, Lafayette, LA
Texas Passive Houses Blaise House, Austin, TX Builder: Equitable Green Group •First Certified Passive House in TX
•1,600 SF remodel of a 1955 house
•double 2x4 stud wall construction w/ cellulose cavity insulation
•energy recovery ventilation w/ inline heating from a hot water heat exchanger
•3/4 ton ductless mini-split for cooling
Texas Passive Houses Blaise House, Austin, TX
Texas Passive Houses Kennedy Residence, Pearland, TX Architect: Liz McCormick, CPHC •new construction w/ 2 separate “passive houses” connected by a dogtrot
•wall system: 2x6 advanced wood framing w/ furred out electrical chase to interior and a rainscreen facade to exterior
•insulation includes cellulose in cavity + continuous mineral wool on exterior -R-22 Walls -R-37 Roof
•energy recovery ventilation •geothermal heating & cooling
Texas Passive Houses Kennedy Residence, Pearland, TX
Texas Passive Houses Kennedy Residence, Pearland, TX
Texas Passive Houses Bass Residence, Lindale, TX Architect: Architend •1,600 SF new construction •wall system: 2x6 advanced wood framing w/ rainscreen facade to exterior
•insulation includes cellulose in cavity + continuous polyiso on exterior -R-27 Walls -R-40 Roof
•energy recovery ventilation •geothermal heating & cooling, CERV, or variable refrigerant flow ducted minisplit
Texas Passive Houses Bass Residence, Lindale, TX
Texas Passive Houses Bass Residence, Lindale, TX
Texas Passive Houses Bass Residence, Lindale, TX
WE NEED EVERYONE’S PARTICIPATION TO GET THERE
JOIN OUR GROWING MOVEMENT
www.phaus.org Passive House Houston
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