Building Energy Efficient Homes: New Construction and Rehab

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Building Energy Efficient HomesNew Construction
and Rehab

• HERS 86 (EnergyStar) minimum
• 30 Better Than the M.E.C.
• Other Considerations
• Affordable Durable Healthy

William Zoeller, R.A.
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Major Systems Affecting Building Energy
Performance

• Building Envelope
• Air-tightness, Insulation levels
• Water-management
• Windows and Glazing Systems
• Glazing SHGC
• Overall U Value
• Heating, Ventilation, and Air Conditioning
• Equipment sizing, efficiency and location
• Duct tightness, distribution effectiveness, and
  location

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Major Systems Affecting Building Energy
Performance

• Domestic Hot Water
• Generation
• Distribution
• Stand-by-losses
• Appliances
• Refrigerator, dishwasher, clothes washer/dryer
• Lighting and miscellaneous

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Panelized Advanced Framing

• Panelized Advanced Framing 2 x 6 Walls _at_24 OC
• Low-e Windows
• Foamed Stud Cavities with Blown in Cellulose
  (R-23)
• Inside-The Envelope AHU
• Foamed and Insulation Buried Ducts
• Affordable and Starter Homes
• HERS 89

Outlook ConstructionAtlanta, GA
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• Panelized Advanced Framing
• Reduces Framing Cost and increases Level of
  insulation
• Reduces on-Site Labor and Construction Time
• Requires Additional Planning, But Improves
  Systems Integration

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Insulation-Buried Ducts
Computer Modeling of Heat Flow From Insulation
Buried Duct
Section Through Foamed Over Insulation Buried Duct
All ducts fully buried with several inches of insulation Larger trunks barely buried and smaller branches fully buried Larger trunks partially buried
R-30 R-15 R-10
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• Buried Duct Benefits
• Improves air distribution efficiency
• Provides additional air-sealing at joints and
  registers
• Reduces Peak load allowing a smaller system to be
  used
• Cost of foam can be offset by reduced cost of HVAC

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PANELIZED WALL AND ROOF SYSTEMS

• 25 Home In-fill Development
• Panelized SIP Construction
• R-24 Walls
• R-40 Roofs
• 92 AFUE Furnaces
• Mastic Sealed Ducts
• 1.2-kW PV Solar Systems
• Low-e Windows
• EnergyStar Appliances
• Compact Fluorescent Lighting
• Controlled Ventilation

Claretian AssociatesSouth Chicago, Il
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• First SIP Project in Chicago
• 155,000 cost for 1700 SF Home
• 5 Increase in Cost of Standard Construction
• 50 Increase in Energy Efficiency

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Panelized Wall and Roof Systems

• Cement Board Structural-Insulated-Panels
• Aluminum-Skinned SIP Roof Construction
• Structural-Steel Moment-Frame at Centerline
• Sold as Pre-Engineered Kit to Builder
• Standard and Custom Designs Available
• Low-Cost and Durable

Homefront Homes
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Cement Board SIP Panels
Panelized Wall Construction System

• Hardie 5/16 thick cement board laminated to
  both sides
• of 4 thick polystyrene foam
• Cuts construction time by up to 75
• High minimum R values with R-20 walls and R-30
  roof
• No wood used in the home construction to avoid
  moisture
• and termite damage

3 days to complete the building shell
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Home Front
Before Hurricane
After Hurricane
Home Front homes proved exceptionally resilient
when Hurricane Charley struck in August, 2004
One mile away.
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Unvented Crawlspace

• Improved Energy Efficiency
• Improved Indoor-Air-Quality

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Low-e Glass Windows

• Low-e glass blocks out most long-wave radiation
  (heat) while allowing most of the short-wave
  radiation (light) to enter.

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Typical Costs

• Extra cost for 300 SF low-e coating on double
  glazing 300.
• Savings in downsizing AC by ½ ton 275.
• Net cost 25.

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Additional Benefits of Low-e Windows

• Reduced cooling load needs smaller HVAC system
• Smaller HVAC system means lower air-flows, and
  simpler pressure balancing
• By being more closely matched to both peak and
  non-peak cooling loads better dehumidification is
  achieved
• (Improves IAQ and inhibits mold growth)

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HVAC Optimization

• Right-Sized HVAC
• Manual J with no oversize
• Compact design
• avoids ducts in outside walls
• Less opportunity for leaks and losses
• Less costly to install
• Better able to achieve air-flows

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• OPTIMIZED HVAC
• Mercedes Homes Townhouses
• Melbourne, Florida

• Concrete and Panelized Construction
• Low-e windows
• Integrated HVAC
• AHU in Conditioned-space
• EnergyStar Qualified

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Down-Sized HVAC
Single Zone 1.5 Ton Capacity Heatpumps Compact
Distribution First and Second Floor
Returns Fresh-Air Duct
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OPTIMIZED HVAC COMFORT TESTING
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Tankless Gas Water-Heater
Madera I Model Home, Gainesville, Florida

• ECO-Block Walls
• Fly-Ash Concrete
• Low-e Windows
• Integrated Compact HVAC
• SEER 17 A/C
• Tankless Water-Heater and Hydro-coil AHU
• HERS 95

Takagi T-KD20
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Cost and Benefits

• Saves Space Much smaller than a storage tank
• Saves Energy Stand-by losses are eliminated.
  Operating efficiency improves by 30 to 40
• Saves Energy For space heating, .84 AFUE is
  higher than standard furnace at .80 AFUE
• Incremental cost increase is about 600. Very
  short initial pay-back, and immediate positive
  cash flow.

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Heat Pump Water Heater

• Installed in a home in Melbourne, Florida
• WatterSaver Integrated HPWH by ECR International,
  Inc. (product introduced Fall 2002)
• Monitoring began in April 2002
• 3-person household (2 adults toddler)

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Preliminary Findings

• Reliable Performance
• Homeowners very pleased
• 62 kWh savings
• 10/month savings at local electric rates of
  .077/kWh

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Energy-Efficient Lighting, Appliances, and
Controls
Takoma Village, Washington, DC
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Takoma VillageWashington, D.C.

• Other Sustainable Features
• Energy Efficient Lighting
• Low-VOC Paints and Finishes
• Fiber-Cement Siding
• Recycled-Content Carpets
• Horizontal-Axis Clothes Washer
• Tubular Skylights

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Putting It All Together

• Warwick Grove,
• Warwick, NY

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Putting It All Together

• Advanced Framing
• Unvented Crawlspace
• Low-E Windows
• Optimized HVAC
• 92 Condensing Furnace
• 13 SEER Air-Conditioning
• Tankless Gas Water-Heater
• EnergyStar Appliances
• HERS 89 -90!