NZEH Seminar


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NZEH Seminar

  1. 1. NZEH A new type of home
  2. 2. NZEH A new type of home • What is NZEH ? • NZEH = Net Zero Energy Home • Basic Requirements • Reduce the energy required to heat and cool the home • Generate on-site energy during the day to export the excess power to the utility [spin the meter backwards] or Store the energy locally [batteries or water tanks] • Import power when the sunny is not out • After a full year, review the energy bills: • Exported power needs to equal imported for: ZERO energy bill !!!
  3. 3. NZEH A new type of home • Where to begin – Don’t Use It!!!! • If you don’t use the energy, you don’t need to make the energy • Super insulate the exterior shell of the home • Super seal the cracks and openings • Use low energy heating and cooling systems • Use low energy appliances and lights • Use low water usage fixtures
  4. 4. NZEH A new type of home • Build it Tight – Ventilate Right!! • Make sure there is a healthy indoor environment • A Standard home [3000 sqft house, 4 bedroom] leaks about 0.15 cfm/sqft = 475 cfm • NEZH = 3000 sqft/100 cfm + [7.5cfm x(1+4 bedrooms)] = 67.5cfm • 67.5 cfm vs 475 cfm (6.5 x less) • Filter the air with large area filters
  5. 5. NZEH A new type of home
  6. 6. NZEH A new type of home
  7. 7. NZEH A new type of home • Make the energy you need locally • Home Brewed Energy
  8. 8. NZEH A new type of home • What type of energy can you make? • Solar PV • Solar Thermal • Wind • Biomass – wood, pellets, bio blocks
  9. 9. NZEH A new type of home • How to Heat and Cool the home • Passive Solar Energy – Windows on South side • Solar hot water – Limited heating capacity • Biomass – May over heat the tight house • Geothermal or VRV Heat pump – uses solar PV energy to operate the systems • Summary – Geothermal and VRV use the home brewed energy and are controllable
  10. 10. What is the Building Envelope?
  11. 11. What is the Building Envelope? • The envelope includes walls, windows and doors between a conditioned area and an unconditioned area. • Areas of concern: – Thermal boundary • Slow the transfer of hot to cold – Air barrier • Seal the air gaps [leakage]
  12. 12. Building Envelope - Guide Books
  13. 13. Building Envelope – Guide Books
  14. 14. Building Envelope Starts With Framing
  15. 15. Building Envelope What’s Wrong With This Picture? Why waste the natural resource of wood? This Doesn’t make the frame better! Advanced Framing •Reduce wood usage 1” wood = R1 •Reduce thermal bridging so 2x6 stud = R5.5
  16. 16. Advanced Framing Reduce Wood Usage OR Earn LEED points – Reduce wood waste
  17. 17. Advanced Framing Reduce Wood Usage Reduce wood waste Transfer of Load
  18. 18. Advanced Framing Reduce Wood Usage – Header Hangers
  19. 19. Advanced Framing Reduce Wood Usage – Drywall Clips
  20. 20. Advanced Framing Reduce Thermal Bridging How it all adds Up to R value • Standard Wall • R19 between studs • R5.5 at studs • Average R17.7 with one 2x6 stud • Average R 15.7 with three 2x6 stud jack • Typical stud wall has an R value of 13ish So every stud reduces the efficiency of the wall insulation
  21. 21. Advanced Framing Outside Corners Notes: •Insulation is compressed/reduced with standard stud corners •Thermal transfer is increased because there is more wood •Drywall will condense water vapor because the temperatures are colder
  22. 22. Advanced Framing Reduce Thermal Bridging Reduces thermal bridging and Allows for fuller depth insulation
  23. 23. Advanced Framing Exterior to Interior Wall Intersection Reduces thermal bridge and Allows for full depth insulation – 2x6 is located behind 2x4
  24. 24. Advanced Framing Insulated Header Used when not on a structural wall Used for a structural wall
  25. 25. Advanced Framing The Double Stud Wall
  26. 26. Advanced Framing The Double Stud Wall Interior Wall with limited Interior Studs[24” o.c.] and Structure Splayed Window with wood sill
  27. 27. Advanced Framing The Double Stud Wall
  28. 28. Building Envelope Air Barrier
  29. 29. Building Envelope Air Barrier • Air Barrier leakage • Air will leak past by any dissimilar materials • Wood on masonry/concrete • Wood on wood • Wood on plastic • Air Barrier can be external or internal • Air sealing around systems • Sealing of air leaks is “fussy” work • Create an Air Boundary that is easily identified and can be installed by the contractor with limited effort
  30. 30. Air Barrier Critical Path • Air Barriers are essential for a NZEH house • Air Barrier must stop air infiltration at the envelope • Barriers must last for the life of the house • Air barriers must be impermeable • OSB, Plywood, Rigid Insulation, etc. • Air barrier must be continuous, so tape all joints • Barrier must not tear apart with forces
  31. 31. Building Envelope Interior Air Barrier
  32. 32. Building Envelope Exterior Air Barrier
  33. 33. Building Envelope Exterior Air Barrier – House Wraps Building wraps - tyvec Typar Tevek
  34. 34. Air Barrier Sealing the Foundation Typical Sill Sealer Gaskets are too thin So Double them up and add caulk
  35. 35. Air Barrier Sealing the Foundation, Sheathing and Decking Use Adhesive and Sealant between each material Seal out leaks by compression of Adhesive
  36. 36. Air Barrier First Line of Defense Seal all joints with primer and flashing tape
  37. 37. Air Barrier Sealing at the Exterior Sheathing
  38. 38. Air Barrier Second Line of Defense 1” XPS, on all Exterior sheathing Dow Weathermate taped at each joint
  39. 39. Air Barrier Third Line of Defense Expanding 0.5 lb Foam in Wall cavities Low Expanding Foam Around Windows and Doors Spray foam expands 100 times its Applied volume, so it seals cracks
  40. 40. Building Envelope Other Leakage Seal all gaps with foam, rigid board, caulking and have patients!
  41. 41. Thermal Boundary OR Summer Winter
  42. 42. Building Envelope Thermal Boundary • The building Thermal Boundary includes all components of a building that enclose conditioned space
  43. 43. Thermal Image of Exterior Wall Insulation has Fallen down Window frame Has more loss that glazing Un-insulated Rim Joist
  44. 44. Thermal Image of Other Items Insulation has Fallen down Window frame Has more loss that glazing Un-insulated Rim Joist
  45. 45. Building Envelope Insulation Zones
  46. 46. Building Envelope Thermal Boundary • Types of Insulation • Fiberglass • Cellulose • Rigid board • Spray foam • Recycle Material • Straw bails
  47. 47. Heat Transfer in Walls
  48. 48. Double Stud Heat Transfer
  49. 49. NEZH - The Wall Section
  50. 50. Building Envelope Testing • Confirming objectives • Air Barriers Inspection at stages • Thermal Boundary Inspection • Blower door testing at critical stages • HERS ratings – Standard Established by Residential Energy Services Network (RESNET) • REMRate Load Analysis
  51. 51. Home Energy Rating • Home Energy Rating System • A standard measurement of a home’s energy efficiency • Measures • Air sealing (ACH@CFM50) • Insulation levels • Window and door efficiency • Heating and cooling system efficiency • Solar orientation • Water heating system • Appliance and Lighting efficiency
  52. 52. Home Energy Rating • HERS Ratings • Energy Audit – a recognized tool in the mortgage process • HERS – provides important information about a homes performance and the economic analysis necessary to support lending decisions NZEH !!!!
  53. 53. NZEH A new type of home