passive houses in texas - atlanta/gacc south houses in texas shelly pottorf, aia, cphc, leed ap...
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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
• 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.
from alan gibsons presentation
47.5
47.5
7.0
200
New Old
•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
What is Passive House?
What is Passive House?
Source: Environmental Building News
Living Building Challenge
(Home Energy Rating System) Passive House buildings use 70-
80% less energy than
conventional buildings.
Passive House
Net Zero feasible!
(90% less energy for space conditioning)
EPA Energy Star V3
Department of Energy
Challenge Home
TAKING IT MAINSTREAM
PLATINUM LEVEL SPONSOR
What is Passive House?
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
GAINS
•Solar heat gain through windows
•Internal gains (same as heating
season)
•Gains through envelope
-conduction
-air infiltration
-radiation
•Gains through ventilation system
LOSSES
•Losses through envelope
-thermal mass
≈
Main Principles of Passive Building
Climate
Specific
Design
Optimize
Thermal
Envelope
Air-
Tightness
Thermal
Bridge Free
Energy Recovery
Ventilation
Minimal
Mechanical
System
Main Principles of Passive Building
Ingredients
• Software uses Detailed Annual Local Weather Data
Tools of the CPHC: x
• Orientation and Size of Windows/Shading Fine-Tuned to Influence Solar Gain Performance
Climate Specific Design
R-Values SHGC U-Value ERV Eff.
• Adjust knobs to balance the energy coming and going from the envelope for specific local climate
COOLING SEASON LOADS
Dehumidification and Cooling Loads from Ventilation Air; ASHRAE Journal, Nov. 1997
BSC charts on latent loads
Climate Specific Design
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 Tools
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
Design
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 mini-
split
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