Cape Cod Passive House

Project Description: 

This is the third house in Massachusetts to achieve PHIUS+ Passive House Certification and the second one in Falmouth.  The home, which is owned by the CPHC and his wife, has a living area of 2,400 ft2.

Building Type Summary: 

single family residence

Other Awards: 

PHIUS+ Certified Project # 1096 April 2014
EPA WaterSense certified 2014
DOE Challenge Home Certified April 2014

Address: 

22 Harbor Ave
Falmouth, MA 02540
United States

Lat. / Long.: 

POINT (-70.599141 41.547935)

Location Type: 

Urban

Köppen Climate Type: 

Cfb

Climate Region: 

Zone 5

Solar Insolation: 

3.80 kwh/m2/day

Annual HDD : 

6091

Annual CDD: 

720

HDD Base Temp: 

65 deg F

CDD Base Temp: 

65 deg F

Occupancy Type and Details: 

owner occupied

Number of stories: 

2

Conditioned Floor Area: 

2 377

Conditioned Building Volume: 

17 710

Semiconditioned Floor Area: 

0

Unconditioned Floor Area: 

633

Multiple buildings?: 

Total number of units in project (all buildings): 

1

Total floor area of project (all buildings): 

2 377

Historic?: 

Completion date: 

Tuesday, December 31, 2013

Site description: 

Flat lot, frontage is true South, 11,754 ft2

Materials: 

Wood construction. Roofing was selected for Energy Star rating. Used paver blocks for driveway to minimize run off.

Energy Highlights: 

Passive House PHIUS+ certified. House designed to face true South. 8.7 kw PV system, sized for house load plus future EV. Pre wired for garage EV electric car charger. Motorized exterior solar shade.

HERS Index: 

-7

Energy Star Score: 

5

Annual renewable energy generated: 

11 434

Power Rating: 

8 745Watts

Electric Utility Company: 

Eversource

Gas Utility Company: 

National Grid

Datasets and Utility Bills sources and reliability: 

source is utility bills and pv meter readings (for SREC program)

Electricity amount (imported from grid): 

0

Electricity amount (credited or exported to grid): 

11 434

Net electricity usage (purchased electricity): 

0

Natural gas amount (purchased energy): 

0

Energy Storage Capacity: 

0

Energy Storage type: 

house naturally stores heat energy in winter due to Passive House construction. No other storage devices are used.

CHP System Description: 

NA

Subslab assembly: 

10 inches of EPS, 6 mil poly sheet, 4 inch concrete, 1.5 inch EPS between sleeper studs. Total of 11.5 inches EPS. R values are for entire assembly from PHPP Model.

Slab edge assembly: 

perimeter thermally isolated from stem wall with 4 inch EPS

Foundation wall assembly: 

10 inch thick concrete stem wall

Above grade wall assembly: 

2x6 16" o.c. outer wall, 4 inch space, 2x4 inner stud wall for a total insulated thickness of 14 inches. 4 inch closed cell foam on sheathing, and 10 inches dense pack dry cellulose. R values are for entire assembly from PHPP Model.

Flat attic assembly: 

24 inches blown in cellulose between trusses. R values from PHPP Model.

Cathedral ceiling assembly: 

NA

Door Area: 

29

Space heating - Manufacturer & Model: 

Daiken Quaternity heat pump 12000 btu FTXG12HVJU & RXG12HVJU

Space heating - capacity: 

5

Space cooling - Manufacturer & Model: 

Daiken Quaternity heat pump 12000 btu FTXG12HVJU & RXG12HVJU

Space cooling - capacity: 

4

Domestic hot water - Manufacturer & Model: 

AO Smith heat pump PHPT-80 (EF=2.33)

Domestic hot water - capacity: 

80

Domestic hot water - efficiency: 

2

Ventilation - Manufacturer & Model: 

Zehnder Comfo Air 350 and Comfo Fond-L

Process: 

Owner and occupant is a Certified Passive House Consultant (CPHC), who worked with the architect to design this Passive House. The CPHC worked with the PHIUS+ Rater and PHIUS to obtain PHIUS+ certification.

Design for Adaptability: 

House was designed to minimize maintenance, water consumption, energy consumption, and chemicals. It was also designed using Age in Place methods for senior citizen living. Lawn is maintained using organic products.

Other Software tools: 

Excel, PVWatt, Climate Consultant

Energy Modeling Software: 

PHPP 2007

Outcome of project goals: 

House has exceeded our expectations. Annual Consumption of electricity is 20%+ less than modeled

Discrepancies: 

None. I found PHPP Model to be fairly accurate for energy usage, after correcting for latent cooling needs.

Total Cost of Project: 

800 000

Construction hard cost: 

500 000

Gross Cost of Renewable Energy System: 

34 600

Value of Tax Credits for renewable energy systems: 

12 400

Net Cost of renewable energy systems: 

22 200

Federal incentives: 

$10,400 for pv

State incentives: 

$2,000 for pv
$7,000 for Mass Save Energy Star new construction

Annual Electric Savings: 

1 400

Annual Revenue from SRECs or other renewable energy credits: 

3 000

Advice: 

Owning PV is preferable to leasing. Take full advantage of incentives (US Federal tax credit for PV, Mass Save Program, SREC program). Passive House construction premium pays for itself in reduced energy bills. Owners are essentially pre paying their energy bills.

Published References: 

Fine Home Building Magazine 6 Issues 2014 and 2015. Publ # 240, 241, 242, 244, 245, & 249
Cape Cod Magazine October 2014

Special architectural measures: 

Passive House design. Exterior Solar shade. Geothermal loop for pre heat and pre cool of ventilation air. PV Solar array sized for all household energy requirements plus future electric car.

Energy Strategies: 

All electric house. No combustion in Passive House envelope.

Energy Use and Production Documentation: 

Subslab R-value: 

48.30

Slab edge R-value: 

16.50

Foundation wall R-value: 

0.30

Above grade wall R-value: 

52.20

Flat attic R-value: 

91.70

Average window U-factor: 

0.15

Solar Heat Gain Coefficient: 

0.62

Visible Light Transmittance: 

0.73

Door U-Factor: 

0.15

Cost per square foot of Conditioned Space: 

210.00

Air Changes per hour, ACH50: 

0.37

Number of Bathrooms: 

4.00

Scope Description: 

Total new construction of single family residence

Site conditions: 

preexisting structure(s)

Renewable Energy Sources: 

Renewable energy is generated within the building footprint (e.g. solar PV on the roof)

Other Purchased Fuels Description: 

no

Storage Strategies & System Details: 

NA

Summary of enclosure strategy/description: 

Walls are double stud construction, 14 inch total insulated thickness

Window Description: 

triple pane wood tilt turn windows with aluminum clad by Makrowin (Yaro). R values are for entire assembly from PHPP Model.

Door Description: 

triple pane argon glass with wood frame aluminum clad, same construction as windows. R values are for entire assembly from PHPP Model.

Mechanical Equipment Installation Details and Comments: 

Each ventilation port was measured and set by a certified Zehnder commissioning expert

Number of Bedrooms: 

4

Project Team: 

Energy Consultant

Team Member: 

Daniel Roy
Energy Consultant

Team Member: 

John Rodenhizer Sr.
Renewable Energy Installer

Team Members: 

Steven Baczek, Architect
Dunhill Companies, Builder
Cotuit Solar, PV System

Status: 

Live

Zero Net Energy Definition Used: 

Site Energy Use

Basis of Performance Claim: 

Zero Energy Program

Type of Construction: 

New

Renewable Energy System Type(s): 

Photovoltaics
Geothermal

Renewable Energy System Description & Details: 

33 Suniva Optimus black modules (USA manufactured Compliant) at 265 watt DC each. Enphase M250 micro inverters.

Annual Renewable Energy Generated Data Type: 

Measured

Source of Annual Production Data: 

11,434 kwh measured year 1 gross annual production (compared to PV Watt predicted of 10,991 or 4% better)

Days per year Building is fully occupied: 

365

Submitter Contact Email: 

Submitter Contact Phone Number: 

(508) 364-1943

Project Type: 

Net Exporter

Lighting Manufacturer and Model: 

LED various manufacturers

Indoor Environment Description: 

All paints and finishes used were either zero or very low VOC. No formaldehyde in construction materials. No indoor carpeting. Continuous MERV 13 filtered ventilation air using Zehnder ERV and ground loop geothermal ComfoFond.

Weight: 

0