NZEH Seminar

NZEHA new type of home

NZEHA 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 !!!

NZEHA 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

NZEHA 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

NZEHA new type of home

NZEHA new type of home

NZEHA new type of home

• Make the energy you need locally• Home Brewed Energy

NZEHA new type of home

• What type of energy can you make?• Solar PV• Solar Thermal• Wind• Biomass – wood, pellets, bio blocks

NZEHA 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

What is the Building Envelope?

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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]

Building Envelope - Guide Books

Building Envelope – Guide Books

Building Envelope

Starts With Framing

Building Envelope

1” wood = R1 so 2x6 stud = R5.5

Why waste the naturalresource of wood?

This Doesn’t make the frame better!

Advanced Framing•Reduce wood usage•Reduce thermal bridging

What’s Wrong With This Picture?

Advanced FramingReduce Wood Usage

Earn LEED points – Reduce wood waste

OR

Transfer of LoadReduce wood waste

Advanced FramingReduce Wood Usage

Advanced FramingReduce Wood Usage – Header Hangers

Advanced FramingReduce Wood Usage – Drywall Clips

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

Advanced FramingReduce Thermal Bridging

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

Advanced FramingOutside Corners

Reduces thermal bridging andAllows for fuller depth insulation

Advanced FramingReduce Thermal Bridging

Reduces thermal bridge andAllows for full depth insulation –

2x6 is located behind 2x4

Advanced FramingExterior to Interior Wall Intersection

Used when not on a structural wall Used for a structural wall

Advanced FramingInsulated Header

Advanced FramingThe Double Stud Wall

Splayed Window with wood sill

Interior Wall with limited Interior Studs[24” o.c.] and Structure

Advanced FramingThe Double Stud Wall

Advanced FramingThe Double Stud Wall

Building EnvelopeAir 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

Building EnvelopeAir Barrier

Air BarrierCritical 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

Building EnvelopeInterior Air Barrier

Building EnvelopeExterior Air Barrier

Building EnvelopeExterior Air Barrier – House Wraps

Building wraps - tyvec

Tevek Typar

Typical Sill Sealer Gaskets are too thinSo Double them up and add caulk

Air BarrierSealing the Foundation

Use Adhesive and Sealant between each materialSeal out leaks by compression of Adhesive

Air BarrierSealing the Foundation, Sheathing and Decking

Seal all joints with primer and flashing tape

Air BarrierFirst Line of Defense

Air BarrierSealing at the Exterior Sheathing

1” XPS, on all Exterior sheathing

Dow Weathermate taped at each joint

Air BarrierSecond Line of Defense

Spray foam expands 100 times itsApplied volume, so it seals cracks

Air BarrierThird Line of Defense

Low Expanding Foam Around Windows and Doors

Expanding 0.5 lb Foam in Wall cavities

Building EnvelopeOther Leakage

Seal all gaps with foam, rigid board, caulking and have patients!

ORWinter Summer

Thermal Boundary

• The building Thermal Boundary includes all components of a building that enclose conditioned space

Building EnvelopeThermal Boundary

Thermal Image of Exterior Wall

Insulation hasFallen down

Un-insulated Rim Joist

Window frameHas more loss that glazing

Thermal Image of Other Items

Insulation hasFallen down

Un-insulated Rim Joist

Window frameHas more loss that glazing

Building EnvelopeInsulation Zones

• Types of Insulation• Fiberglass• Cellulose• Rigid board• Spray foam• Recycle Material• Straw bails

Building EnvelopeThermal Boundary

Heat Transfer in Walls

Double Stud Heat Transfer

NEZH - The Wall Section

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

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

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 !!!!

NZEHA new type of home