1. System Elements
2. Element Costs

Ceiling Insulation

•  Blown in fiberglass to R60 in attic.
•  Sloped section over stairs used rigid Exeltherm Extra™ by Koppers to R50.
•  Raised heel trusses.
•  Designed for vented attic in summer and unvented attic experiment in winter.

•  Two 2x4 walls, each at 16" o.c.
•  Walls spaced 6" apart to allow R22 fiberglass batt placement between them.
•  R13 fiberglass batts placed in both 2x4 walls.
•  Total wall insulated to R45.

•  Roughly R48 fiberglass batts to top of footing.
•  R25  fiberglass batts on ground.
•  Plenum ceiling (3/4" T&G plywood subfloor) holes sealed.
• Wall bracing nail locations logged on plans and later sealed.
• Search for any undiscovered holes in subfloor air barrier just prior to carpet and linoleum.
• Tracer gas injected into sealed plenum and 2 nail holes detected.

•  Different shading coefficients depending on solar orientation.
•  Heat Mirror™ units with 10 year warranty used throughout.
•  Standard patio sized,  tempered units used extensively to save cost & enhance safety.
•  See plans and window schedule for detailing

•  Used Swedish "P" gaskets for gasketed drywall to create rigid air barrier.
•  Used urethane sealants to seal T&G subfloor, plates, and other framing joints.
•  Used siliconized acrylic latex to seal wiring penetrations.
•  Used EPDM rubber sheet to create "slip boot" around plastic plumbing penetrations.
•  Used Tremco™  & Henries 313™ acoustical sealants for crawlspace air barrier.
• Infrared thermography study was conducted and several minor air leakage locations were identified and sealed.
• The door-fan tested air change rate was 1.2 Air Changes per Hour at 50 Pascal of induced indoor/outdoor pressure-difference. After one year of occupancy the leakiness of the building had not significantly changed (1.4 ACH @ 50 Pa).

• Unique vented rain screen between exterior sheathing and siding.
• Tight envelope to prevent air transported moisture into walls and attic.
• Unvented attic experimentation.
• Vapor diffusion retarder: latex paint primer at less than 1 perm by both wet and dry cup test methods.
• Depressurization of occupied zone by continuous ventilation system.
• Pressurization of "crawlspace"  zone by continuous ventilation system.
• Moisture monitoring study to evaluate moisture control

• Heat Pump ventilator used to provide space conditioning and water heating.
• HPVAC80, by Dairy Equipment Corp. International, Inc.
• DEC claims unit uses 1/3 energy of electric resistance space and water heating.
• Earth tubes precondition winter supply  air to 45°F or more.
• HPVAC80 always operates well above balance point.
• Earth tubes precondition supply  air in summer, increasing cooling efficiency.

HPVAC80 provides free cooling during summer when in water heating mode.

COST INCREASES BEYOND TYPICAL NEW HOME:

Heat Recovery Ventilation, Heating, & Cooling
  also water heating and pressure-difference control

HPV80-AC delivered cost	$1,600
house to crawl exhaust ductwork, grilles	$1000
speed controllers & clock timers	$80
make-up air via earth tubes (see earth tubes below)	$833
supply side ducts & grills	$1,510
installed supplemental zonal baseboards and controls	$500
avoided kit/bath fan costs	($260)
avoided hot water tank	($350)
avoided conventional forced air elect. heating system	($2,500)

  Net cost over conventional construction  $2,413
 

Earth Tube
  partially conditioned make-up air both summer &  winter

excavation & fill	$50
42" diameter  galvanized culvert	$89
4" PVC tube	$238
tube installation labor	$98
intake housing (waste materials & 2 days owner labor)	$240
filter box	$79
filters	$20
house entrance box	$20

Net cost over conventional construction  ($833 is in HVAC costs above)

Crawlspace Insulation  & Air/Vapor Control
  walls @ approximately R45 and ground @ R25

astm #67 gravel (13.5 yd3 @ $7/yd + labor)	$202
17 (4'x8'x3/8" wafer wood)	$93
380' of 2"x2"  &  80' treated 2"x4"	$75
1600 drywall screw @ $2.39/lb & concrete anchors	$72
framing labor by owner: 30 hours @ $15/hour	$450
wall and floor insulation material	$690
insulation labor by owner: 20 hours @ $15/hour	$300
sealants & foil vapor retarder	$106
avoided venting costs (6 @ $30 each)	($180)
avoided ground cover costs @ $.08/ft2	($94)
avoided floor insulation: R30 for 1227 ft2 @ $.54/ft2	($663)

Net cost over conventional construction  $1,051

Double Wall
  two 2x4 walls @ 16" o.c. & 5.5" apart

600 studs @ $1.20 ea.	$720
1880' plates  = 1260 bf @ $250/m	$315
headers 425 bf	$137
26 (4'x8' plywood plate ties)	$142
framing labor	$1,300
R13+R22+R13 fiberglass batt for 2365 ft2	$1,242
insulation labor	$382
avoided 300 studs @ $1.20 ea.	($360)
avoided 940' plates  = 630 bf @ $250/m	($158)
avoided headers	($90)
avoided framing labor	($700)
avoided R 19 batt @ 16" oc for $.30/ft2 installed	($710)

Net cost over conventional construction  $2,221

Ceiling Insulation
  Insulated to R60.  R38 is conventional.

R 60 for 1276 ft2	$750
avoided conventional insulation to R38	($508)

Net cost over conventional construction  $242

Air Leakage & Air-Transported Moisture Control
  1.4 ACH @ 50 Pa

$0.45/interior ft2 & included door fan testing	$801
owner labor: seal tub surrounds, stairwell, & rim joists	$188
urethane	$161
avoided conventional air sealing	($50)

Net cost over conventional construction  $1,100

Moisture: Vapor-Diffusion Retarder
  both wet and dry cup @ less than 1 perm

columbia vapor shield 02-725-PP primer 350 ft2/gallon @ $12/gallon	$124
avoided non vapor retarder primer or poly	($124)

Net cost over conventional construction  ($0)

Glazing
  314 ft2 total:  18% conditioned floor area

units w/ sash (84 ft2)	$1,266
site built (glazing only @ 230 ft2)	$2,349
site built glazing installation (estimated @)	$970
263' outside stops @ .30/ft	$79
glazing tape purchase	$37
sealant @ $3.50/tube	$70
mek	$16
plywood bases	$50
263 ft. inside stop @ $.50/ft.	$132
sheetrock returns @ $1/ft.	$263
labor (assumed @ 50% materials)	$323
avoided $1.80/ft2 by using site built ***	($414)
avoided conventional glazing cost @ $8.52/ft2 ****	($3,020)

Net cost over conventional construction  $1,151

 ***   $/ft2 of installed site-built windows compared to $/ft2 of installed units.
 ****  Based 1989 study reported in Northwest Builder 12/90, p3..

Incentive Payments

rcdp future house	$1,000
rcdp air leakage control project	$350
rcdp occupant monitor agreement	$300
nwec early adopter payment	$2,468

 Net benefit over conventional construction  ($4,118)

TOTAL INCREMENTAL COST (not allowing incentive payments)    $8,177
TOTAL INCREMENTAL COST (allowing incentive payments) $4,059
 

Average Annual Space Heating Energy Use & Cost   Kwh @ $.05/Kwh
This Residence   4502 @ $225
Conventional Northwest Home ^   12,420 @ $621
 

SIMPLE PAYBACK ENERGY ONLY (not allowing payments) ^^   21  Years
SIMPLE PAYBACK  ENERGY ONLY (allowing payments) 10  Years
 

^   Based on average measured conventional homes in RCDP (see energy scection).
^^  Based on energy benefits only and at current electrical rates.