COST DRIVERS IN PHIUS AND

ZERH HOME CONSTRUCTION

Patty Shields, LEED APMetro Green, LLC

Falls ChurchResidential Builders

Donaldson Run Passive House

PHIUS Certified 2015

Other certs – LEED, ZERH, Energy Star, Earthcraft, Green Home Choice

Keys to success• A good plan and a team that gets you there

• Motivated client with realistic expectations• Experience/motivated builder• 3rd Party Rater • Energy Star Certified HVAC Installer

• PHIUS, ZERH, Energy Star and IAQ Plus

Cost drivers

• Material Costs• Labor

• Quality Control

Cost Implications by PHASE

Design and Spec development:

• Passive Solar Design inputs• Energy Modeling • Wall assembly, fenestration,

Mechanical plan• Assembling your team – Experience,

curiosity, motivated

Help your builder with good details

FoundationInsulation, Eliminate Thermal Bridges, Vapor barrier

FramingReducing Thermal Bridges and High R• double wall, outsulation, SIPs

VAPOR

RETARDER

Windows:PH certified triple glaze windowsCost and Installation v double glaze

Exterior WRB and AirsealingOutsulation v Zip-R v peel and stick continuous

Testing:Smoke tests, real tests, and what they reveal: KEEP IT SIMPLE

Insulation Approaches:• Flash foaming – Closed Cell• Open Cell at bands• Dense pack cellulose, rockwool• Quality CONTROL

Mechanicals:

• Heat Pumps with VRF – Variable Refrigerant Flow • Mini-Splits• Whole home

• Ventilation Strategies – ERV • Dehumidification

Mechanical Install:• Who is your installer?• Energy Star certified? Motivated?• Sealing the ducts – QUALITY

CONTROL• Mastic, Flash foaming for

condensation• Testing – Duct Blaster

Final Testing and Commissioning:

• Duct Blaster• Blower Door• Balancing• Documenting Lessons Learned

Lessons Learned:

• Understand your client’s real goals:• Reduced carbon footprint

• Embodied energy- tear down

• IAQ• Energy independence

• Solar needs to be in the mix

• Thought leader – exemplar

What Cost Balancing do we grapple with most:

• Solar PV v PH certified windows• Venting dehumidification v ERV + dehu• Outsulation v ZipR v closed cell flash

Patty ShieldsFounderMetro Green LLCFalls Churchwww.metrogreenhome.commetrogreenllc@gmail.com