Construction Report NYSERDA Residential Performance Challenge WELYTOK TOWNHOMES October 2014 Submitted to: NYSERDA 17 Columbia Circle Albany, NY 12203 Submitted by: HOMEPIC Team CDH Energy Corp. PO Box 641 Cazenovia, NY 13035 315-655.1063 And Syracuse Center of Excellence in Energy and Environmental Systems Camroden Associates
House Description Mark Welytok of New-Paradigm Developers plans to build nine (9) townhomes on the southern shore of Oneida Lake in the town of Chittenango, NY. Our team helped to develop an energy efficient design for these nine (9) units. The first four (4) units are scheduled for completion in 2014. The HomePIC project is supporting the improvements to these one of these first four units. These two-story units have a slab-on-grade foundation with 4 rigid foam under the poured concrete slab. The foundation footings use an Insulated Concrete Form (ICF) wall system that uses 2 of expanded polystyrene (EPS) on each side as forms for the footings. The exterior walls were designed with 2 of exterior rigid foam where possible, with 5½ closed cell spray foam in the framing in other areas. Build Site Figure 1. Aerial View of Building Lot (SOURCE: Bing Maps) Figure 2. Homes Under Construction HomePIC Team 1 October 2014
Key construction details are summarized in the following Figures. Table 1 compares the originally proposed improvements to actual implemented features. Table 2 summarizes the costs of the implemented improvements. The floor plan is given below. DOWNSTAIRS UPSTAIRS Figure 3. Floor Plan for East-Side End Unit HomePIC Team 2 October 2014
Foundation The foundation construction details include the ICF foundation walls and 4 rigid foam under the concrete slab. The builder installed ½ PEX-Al-PEX tubing in the slab for future radiant floor heating. Figure 4 shows the ICF forms from Fox Blocks partially filled with concrete. Plastic clips inside the blocks maintain the spacing of the foam sides. Rebar is installed vertically and horizontally to provide additional strength. ICF Figure 4. ICF Foundation Walls Figure 5 and Figure 6 show the insulation under the concrete slab. Figure 5 shows the 4 foam board on top of the plastic vapor barrier. Figure 6 shows the installed ½ PEX-Al-PEX tubing for radiant heating on top of the 4 foam and steel reinforcement. HomePIC Team 3 October 2014
4 Polystyrene Foam Figure 5. 4" Foam Installed Under the Concrete Slab ½ PEX-Al-PEX Tubing Figure 6. PEX-Al-PEX Tubing Installed for Radiant Floor Heating HomePIC Team 4 October 2014
Exterior Walls and Framing The exterior walls have 2 rigid exterior foam with taped seams, spray foam, and other details. Figure 7 shows the 2 rigid foam being installed on the east wall of the structure. This foam was isocyanate panels recycled from a school roof. The foam seams were (supposed to be) sealed with tape for air tightening. Figure 8 shows the open cell spray foam in the exterior walls with exterior rigid foam. Exterior walls without exterior foam have closed cell spray foam installed to provide a thermal and vapor barrier. Figure 7. Start of Installation of 2 Exterior Rigid Foam on East Wall Open Cell Spray Foam on All Exterior Walls with Exterior Foam Figure 8. Open Cell Spray Foam on East Wall HomePIC Team 5 October 2014
Figure 9 shows the California corner stud arrangement used in the framing of the exterior walls. This configuration provides access to the end of the framed wall for good insulation with minimal thermal bridging. California Corner Figure 9. Typical California Corner Windows All windows are double hung, vinyl frame, triple glazed, argon filled, and dual low E coated. The U- Factor is 0.21 and the Solar Heat Gain Coefficient (SHGC) is 0.22. The window rough openings were extended with 2x4 s and ½ rigid foam to build out the opening to the same height as the exterior foam board. The window flanges were then nailed to the 2x4 with ½ foam. Figure 10. Window Specifications HomePIC Team 6 October 2014
Ceilings, Rim Joists, and Firewalls Figure 11. Cathedral Ceiling with 7 to 8 of Colsed Cell Spray Foam Spray Foamed Rim Joist Figure 12. North Wall and Rim Joist with Closed Cell Spray Foam HomePIC Team 7 October 2014
Closed Cell Spray Foam on Exterior Portion of Common Wall / Firewall Paper Faced Fiberglass Insulation in Adiabatic Portion Common Wall / Firewall Figure 13. Firewall Between Units Figure 14. Firewall Between Units with Bottom Plate Spray Foam Sealed HomePIC Team 8 October 2014
Figure 15. Garage Ceiling (closed cell) and Garage Wall (open cell) Figure 16. Closed Cell Spray Foam in Dormers and Walls on Lake-Side HomePIC Team 9 October 2014
Figure 17. Cathedral Ceiling and Knee Wall with Closed Cell Spray Foam HomePIC Team 10 October 2014
Mechanical Systems The townhouse complex will not have natural gas. Therefore the space and water heating will be done with solar and electric systems. Each unit will have a separate solar hot water tank with electric backup. The tank will be connected to in-floor piping so that solar can also contribute to space heating. Space heating and cooling will be provided by a high performance heat pump such as a Mitsubishi Hyper-heat or Fijitsu RLS series unit. The unit should be a 2 or 2-½ ton unit with a concealed indoor fan unit, such as Mitsubishi Hyper Heat Pump PUZ-HA30NHA2 with PEAD-A30AA4 indoor unit shown below. Figure 18. High Performance Heat Pump With Concealed and Ducted Indoor Unit (from Mitsubishi) The indoor unit can be mounted above the washer/dryer in a drop ceiling with very limited ductwork runs (i.e, under 4 ft) to a few locations: 1. to lake-side master bedroom on the first floor 2. through the wall to main area on first floor 3. through the floor to floor vent in the upstairs loft 4. through the floor to a floor vent in the upstairs study A return grill would open to the main areas of the house. The remaining areas of the house (such as the front bedrooms #2 and #3) would have baseboard electric heat. About 6 kw of baseboard heat would be required. HomePIC Team 11 October 2014
Table 1. Recommended Thermal Envelope Details Base Design Improved Design Walls 2x6 Frame and Fiberglass Batt. R19 2 Rigid Foam Insulation on exterior of OSB 2x6 frame, Open Cell Spray Foam in Wall Cavity. ~R33 Lake-Side Walls and Dormers 2x6 Frame and Fiberglass Batt. R19 Closed Cell Spray Foam in Wall Sections w/o Exterior Foam. ~R30 Attic Scissor Truss with 2x4 Bottom Cord 11.5 Fiberglass Batt. R38 Scissor Truss with 2x4 Bottom Cord 16 Cellulose. ~R50 Cathedral/Vaulted Ceiling Foundation Walls and Slab Garage Walls and Ceiling 2x4 Parallel Cord Truss with Fiberglass Batt. R38 Poured concrete. 2 foam board on footer Fiberglass Batt 2x4 Parallel Cord Truss with 7-8 Closed Cell Spray Foam. ~R42 ICF Forms with 2.5 Foam on Each Side of Poured Concrete. 4 Rigid Foam Under Poured Concrete Slab Closed Cell Spray Foam in ceiling Open Cell Spray Foam on exterior walls Windows U=0.31, SHGC=0.35 (double hung) U=0.22, SHGC=0.20 (double hung) Rim/Band Joists 5.5 inches of Fiberglass. R21 Caulked and Spray Foamed. Garage-to-Interior Wall Fiberglass Batt, 2x6 Framing. R19 Blown Bagged Cellulose, 2x6 Framing. R19 Air Tightness 5 ACH50 2 ACH50 Various air sealing and thermal bypass improvements DHW Electric water heater Solar Hot Water System Heating and Cooling 92.5% Efficient Gas Furnace Solar HW tank connected to Radiant Infloor Heating 2 or 2-½ ton Hyper heat pump with some electric baseboard heaters. Ventilation Exhaust Only Ventilation Exhaust Only Ventilation HomePIC Team 12 October 2014
Table 2. Summary of Capital Cost Differences HomePIC Team 13 October 2014
Energy Performance The enegy use predicted by RemRate for the proposed house design is shown in Table 3. The RemRate model assumed an air-source heat pump with a heating seasonal performance factor (HSPF) of 6.8 Btu/Wh (which equates to a seasonal COP of about 2). Table 3. Summary of Energy Use for Proposed Design Heating (kwh) Cooling (kwh) DHW Load (MMBtu) Lights and Appliances (kwh) Total Electric (kwh) Proposed Energy Use 5,315 1,211 12.4 6,449 12,975 HomePIC Team 14 October 2014