Building Energy Efficient Homes:New Construction and Rehab HERS 86 (EnergyStar) minimum 30% Better Than the M.E.C. Other Considerations: Affordable; Durable; Healthy William Zoeller, R.A.
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
Major Systems Affecting Building Energy Performance • Domestic Hot Water • Generation • Distribution • Stand-by-losses • Appliances • Refrigerator, dishwasher, clothes washer/dryer • Lighting and miscellaneous
Panelized Advanced Framing • Panelized Advanced Framing 2 x 6 Walls @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
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
Insulation-Buried Ducts Computer Modeling of Heat Flow From Insulation Buried Duct Section Through Foamed Over Insulation Buried Duct
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
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
First SIP Project in Chicago • $155,000 cost for 1700 SF Home • 5% Increase in Cost of Standard Construction • 50% Increase in Energy Efficiency
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 Panelized Wall and Roof Systems Homefront Homes
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
Home Front Before Hurricane After Hurricane Home Front homes proved exceptionally resilient when Hurricane Charley struck in August, 2004 One mile away….
Unvented Crawlspace • Improved Energy Efficiency • Improved Indoor-Air-Quality
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.
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.
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)
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
OPTIMIZED HVAC • Mercedes Homes Townhouses • Melbourne, Florida • Concrete and Panelized Construction • Low-e windows • Integrated HVAC • AHU in Conditioned-space • EnergyStar Qualified
Down-Sized HVAC Single Zone 1.5 Ton Capacity Heatpumps Compact Distribution First and Second Floor Returns Fresh-Air Duct
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 Tankless Gas Water-Heater Madera I Model Home, Gainesville, Florida Takagi T-KD20
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.
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)
Preliminary Findings • Reliable Performance • Homeowners very pleased • 62% kWh savings • $10/month savings at local electric rates of $.077/kWh
Energy-Efficient Lighting, Appliances, and Controls Takoma Village, Washington, DC
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
Putting It All Together Warwick Grove, Warwick, NY
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!