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. 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. 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
7. NZEH
A new type of home
• Make the energy you need locally
• Home Brewed Energy
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. 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
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]
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
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. 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. Advanced Framing
Reduce Thermal Bridging
Reduces thermal bridging and
Allows for fuller depth insulation
23. Advanced Framing
Exterior to Interior Wall Intersection
Reduces thermal bridge and
Allows for full depth insulation –
2x6 is located behind 2x4
24. Advanced Framing
Insulated Header
Used when not on a structural wall Used for a structural wall
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. 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
38. Air Barrier
Second Line of Defense
1” XPS, on all Exterior sheathing
Dow Weathermate taped at each joint
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. Building Envelope
Other Leakage
Seal all gaps with foam, rigid board, caulking and have patients!
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. 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. 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 !!!!