1. Deep Energy Retrofit (DER) Workshop
January 12, 2013
Sustainable Living Resource Center
Cottekill, NY
Thank you
Manna Jo Greene

2. Why DER is Needed …
Fuel sources, therefore fuel prices are volatile, provides “hedge”
Operating costs burden homeowners, money exits local economy
Current weatherization/Home performance strategies
(insulation placed between studs, 15% reductions, incremental benefit)
vs.
Deep Energy Retrofit strategies
(install insulation to exterior, air seal, reduce mechanicals, 65 – 75% reductions, provides step function boost benefit)
Benefits to preserving entrained energy of existing stock

3. Age of Existing US Housing Stock
Almost 60 million housing units built before the first oil embargo in 1973
Most homes in the US could benefit from some sort of energy retrofit. There is a huge potential market for improvements.
Source: American Housing Survey 2005
© Marc Rosenbaum - EnergySmiths

4. Candidates for DER … both built within the past 20 years
Credit: Marilyn Kaplan
Credit: Tony Abate

5. There are several strategies for implementing a DER; this Pilot focused on the exterior insulation strategy for the following advantages:
Allows continuous, un-bridged insulation layer
Facilitates exterior air barrier installation
Can be installed while the home is occupied
Thickness of insulation is not limited by wall thickness
Eliminates the problems caused by blocking, bracing and other internal framing elements causing missed (un-insulated) wall cavities

6. Condensation Potential
All buildings go through wetting and drying cycles.
The drying ability must be greater than the wetting potential or moisture related problems will result.
Chart shows the period of time during which the outdoor temperatures reach below indoor dew point, making condensation possible, and it will occur somewhere within wall and roof/attic assemblies.
This is important because the building must be able to dry at a greater rate than it gets wet.
Heat loss is the main moisture mover in winter, but as we insulate the building, we decrease conductive heat loss and therefore improve the drying potential of the building.

7. Temperature gradient across a wall
Note that the temperature of the interior face of the sheathing is 20F – well below the dewpoint of the inside air.
If air from the inside reaches the sheathing in any significant amount, condensation will occur.
Air leakage through a small hole can move 100 times more water into a building cavity than is transported by vapor diffusion, so air barriers (AB) are more critical than vapor diffusion retarders (VDR)
With 2 inches of polyiso at R-13 the interior face of the sheathing is 41F – little condensation risk.
Applying exterior insulation (especially continuous high-R value insulation) will increase the winter temperature of wood sheathing underneath, decreasing the wetting potential, notice the ‘knee’ in the curve
In Cold Climates, building durability is in a large part determined by how effectively the building exterior envelope handles moisture and temperature gradients.
Thermal bridging causes cold spots on the interior side of exterior walls when the temperature of the wall is below the dew point of the indoor air.
In winter, moisture is evaporated into relatively dry indoor air from people, cooking, basements…
As air circulates over colder exterior elements (where the thermal bridges are) it cools and reaches dew point, dropping moisture and potentially causing moisture damage
© Marc Rosenbaum - EnergySmiths

8. Foam (SPF) placed ON the wall is a strategy that reduces thermal
Heat flow and R values in walls
Foam (SPF) placed ON the wall is a strategy that reduces thermal
bridging.
2x6 cellulose 18% wood
Nominal R21, Actual R = 15.8
77% of nominal R21
2x6 cellulose 18% wood 4” SPF
Nominal R45, Actual R = 41.0
90% of nominal R45
Credit: Marc Rosenbaum (Energysmiths)

9. Major Renovation Invokes Building Permit … eliminates “kicking the can”

10. Air Infiltration Measurements
ACH before DER
ACH after DER

11. Average Total MMBTU / Unit (4 Utica Houses)

12. Phase II … PON 2254, Exploratory Envelopes
Develop repeatable strategies that scale
Achieve following technical objectives:
Whole house assembly, R > 25
Total air leakage, < 0.25 CFM50 / ssf
Labor & material / ssf = $10
Combine strategies to optimize influence
Acquire more data, 22 is more than 4, statistics

13. 5 Building Science Contractors Selected, 22 homes
Taitem Engineering (retrofit 4 houses)
Snug Planet
NAHB – Research Center (retrofit houses)
SIPA
IBACOS (retrofit 8 houses, and 1 control)
Green Homes America
Verdae (retrofit 3 houses)
Mulder Construction
Levy Partnership (retrofit 3 houses, MF)
Sto Corp

14. Material Intensive in both directions …

15. Reduced Mechanical Systems enables energy reductions

16. Continuous Mechanical Ventilation that works

17. Homeowner Engagement, More Emphasis needed on promoting “comfort”
Air quality
Safety (removal of auxiliary heat sources)
Insurance premiums (no ice damming, falling ice)
Building quality/integrity
Value the ‘resilience’ of the solution
Better sound attenuation (indoors is quiet)
Improves longevity of equity investment
Thermostat settings at occupant desired levels

18. Direct Benefits of Screwing 4” of Rigid to Exterior
Works daytime, nighttime
Works summer, winter
Eliminates undesirable air leakage
Employs local labor
Invokes building permit, which brings house to code
Works when grid is de-energized
Works on cloudy days
Works when wind is not blowing

19. Long Ways away from a “Program” …
Allies Needed
Regulators
Bank appraisers
Code officials, consistency
Siding contractors
Realtors
Insurance underwriters
Project agent
Manufacturers discounts
Slush fund investment to code comply homes
Policies Needed
Carbon taxes
Fuel oil taxes to fund Bldg Science
kBTu/ft2/yr threshold
Reward for less

20. Contact… gap@nyserda.ny.gov http://nyserda.ny.gov/advanced-buildings
Greg Pedrick, C.E.M.
Buildings R&D Project Manager
17 Columbia Circle
Albany, NY 12203
(518) , x3378