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A presentation on Cold-Climate Deep Energy Retrofits made to the Technical Research Committee of the Nova Scotia Home Builders' Association, October 2010. Includes a case study and some highlighted construction details that could be stumbling blocks to a successful Deep Energy Retrofit.
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Deep Energy Retrofits"
Shawna Henderson, CEO"Bfreehomes Design Ltd."
Energy Efficiency programs aim for a 20 to 30% reduction in space and water heating needs."A deep energy reduction aims for 50 to 90%."
12 house types, 6 cities"
Range of ages:"1922 to 2000"
1. "How does house type/age affect NZEEH?"
2. "How does climate affect NZEEH?"
Approaching Net Zero Energy in Existing Houses"
13.2 million existing homes in Canada, approx 98% of overall housing stock"
"Nova Scotia: nearly 50% pre-1970"
Halifax: dwindling land resources in city, increasing sale prices"
"Situation!
Higher energy prices, older houses: OPPORTUNITY TO GO DEEP"
Challenge"Qualified trades, Financing"
1” type 4 foam on 2x4 walls = Lost Opportunity R10 or R12 + R5 = R15 to 17 "
(vs. new code R24 min … what does resale look like in 5 years?)"
3” foil-faced polyiso as ext air barrier: "R10 or R12 + R18 = R28 to 30"
Don’t be tempted by the low hanging fruit!""
House Yoga – Flexibility & Endurance""
Where is dew point?"What is first condensing surface?"Small extra cost vs. big energy savings?"
Ceiling Main Walls ExposedFloors
BelowGradeWalls
Slab
Vancouver 10.6 (60) 7.0 (40) 7.0 (40) 7.0 (40) 1.8 (10)Calgary 14.4 (80) 10.6 (60) 10.6 (60) 7.0 (40) 1.8(10)Toronto 10.6 (60) 7.0 (40) 7.0 (40) 7.0 (40) 1.8 (10)Montreal 14.4 (80) 10.6 (60) 10.6 (60) 7.0 (40) 1.8 (10)Halifax 10.6 (60) 7.0 (40) 7.0 (40) 7.0 (40) 1.8 (10)Whitehorse 14.4 (80) 10.6 (60) 10.6 (60) 7.0 (40) 1.8 (10)
Approaching Net Zero Energy in Exis4ng Houses
Upgraded Envelope Targets (RSI/R) Averages from superinsulated houses built/designed in the last 5 years
in Canada and northern US, incl. EQuilibrium House Initiative projects
Assumptions we can challenge"
The diminishing returns on insulation limit thermal envelope improvements""Windows have crappy performance"
Canadian houses need full-size, central heating systems"
Energy availability and low prices will remain stable, so it’s business as usual"
Renovation Pyramid"
The Envelope, Please!"
Doors, windows replace/repair/retrofit""Lower envelope requirements = "Lower energy needs = "smaller space conditioning requirements"
Focus on draftproofing, then insulation""foundation up"
Space 65%
Water 17%
Appliances 13%
Ligh4ng 5%
As Is
Space 57% Water
21%
Appliances 16%
Ligh4ng 6%
Conven*onal
Space 33%
Water 8%
Appliances 46%
Ligh4ng 13%
DER with Solar Thermal
Shift the relationships between purposes and energy use""
0
50
100
150
200
250
300
350
400
As Is Conven4onal DER with solar
Energy Use Comparison
Ligh4ng
Appliances
Water
Space
50% reduc4on
80% reduc4on
Meeting DHW load becomes becomes bigger challenge than space heating as envelope improves"
#1: get rid of water problems"
A: No direct contact w/concrete or masonry walls or floors for moisture sensitive materials"B: Moisture tolerant materials are not in contact with materials that will absorb water if there is problem"C: Airtight construction on foundation walls and floors warms first condensing surface, mitigating moisture issues in living space"
Plumbing and electrical services run in front of 2 lb foam insulation and behind standoff wall – full depth insulation throughout basement and header area"
#2: don’t invite them back"
Above-Grade Insulation"‘flash and batt’ interior strap-out or standoff"
Min. 2” layer of 2lb foam for air barrier"
!!! HEADER ALERT!!!"
"
Biggest issue: DER with exterior insulation can make wall more vulnerable to leaks and damage" Especially at
attached shed roofs "
Especially with windows above"
Especially in areas prone to horizontal driving rain"
Picture from BSI presentation at ACI New England 2010: Windows: i.e., The Holes in Your Wall
OMG!!! BFFL!!!The Whole House Drainage Plane"
Illustra4on from www.buildingscience.com
Another Bestie:"Pan Flashings"
Outies Rule!"Extended ½” ply window bucks flush with 3 to 4 inches of exterior foam"• Simpler drainage plane connections and geometry"• Lower cost (extra trim is interior material – we use drywall)"• Similar appearance to original, tie in w/neighbourhood"
Innies:"Window is in same plane as original wall"• Perhaps greater protection from wind-driven rain from inset"• Some additional solar shading"• Can use existing window trim"• If windows are not going to be replaced, what choice?"
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5- year payback based on $ spent vs. energy savings not the whole story – how to quantify comfort?"Windows, siding = ‘permanent’ components w/20 yr planning horizon"
Comfort Envelope = Thermal Envelope"
Inside glass temp affects rate at which occupants radiate body heat to the glazing. "
It also impacts condensation and moisture issues in a house as envelope is improved."
Mechanical ventilation required in DERs "
With low space heating loads: can we use ventilation system to distribute heat a lá PassivHaus?"
Window Comfort 1"
4 factors:"Air Temperature"Mean Radiant Temperature"Relative Humidity"Air Movement"
Window Comfort 2"
Mean Radiant Temp/"Air Temperature"
Air Movement/"Relative Humidity"
OK, 5:"Proximity"Where are you comfortable?"…1’ …2’ …3’ …4’ from wall?"Cuts down on useable room size to stay comfortable – forget issue with thick walls!"
Thermal Envelope shortcomings can be fixed by improving equipment efficiency""Comfort Envelope shortcomings leave complaints, customer dissatisfaction and"increased energy expense and pollution because of higher thermostat settings.""Work with Thermal/Comfort Envelope."
Thermal/Comfort Envelope"
From this …"
… to this "(reasonable facsimile of system)"
97% efficient, 50k Btu natural gas condensing boiler augmenting solar thermal system "DHW and space heating delivered via dual-coil, 120 gallon storage tank"
Two of each:""60% efficient, 120k Btu oil boiler ""80 gal. electric water heaters + indirect tank, uninsulated in unconditioned space"
Oh, ya, mechanicals…"
From monster cast iron rads EVERYWHERE to infloor radiant at 12 and 16 inch o/c"
From high-temp hydronic baseboards EVERYWHERE to a
few wall-hung low-temp rads"
House as an Investment"
Define investment period"What’s in your pocket at the
end? ""
Alternatives …"Scenarios for house"Scenarios for money"
Resale-ability?"Non-energy benefits?"Investment horsepower?"
What makes us tick?"
Spending decisions NOT based on bottom line:"– Comfort, safety, peace of mind"– Personal goals"– Ego gratification"– Justification leads to cherry-picking"– Community leadership"DRIVERS ARE NON ENERGY BENEFITS"
Value of Non-Energy Benefits…"…to utility
Transmission /distribution savingsPeak load restrictionsReductions in arrears and late payments/write offs/bad debtReduced regulatory costs and discount paymentsReduced emergency service calls"
…to societyEconomic impacts (job creation/tax revenue)Improved housing stock/preservation Emission/environmental impactsHealth and safety benefitsWater and wastewater savings"
"
What do all of these benefits have in common? "
They can be quantified."
How does the Homeowner/Ratepayer Gain from Non-Energy Benefits?"
Financial"Comfort"Aesthetics"Health and safety"Noise reduction"Education-related"Convenience"
What do all of these benefits have in common? "
Except for #1, they are difficult to quantify objectively."
Broader, clearer financial analysis"
Financial analysis does not begin and end with payback on a product – Return on Investment (ROI) is clearer indicator of how and where clients can best spend their money"
EE Investment/Energy Costs"Oil " "$8,100"Electricity "$7,300"Nat Gas "$4,000"
Conventional: $22k"
Deep Energy Retrofit: $37k"
DER w/solar combi: $52k"
Oil " "$5,100"Electricity "$4,600"Nat Gas "$2,600"
Oil " "$2,100"Electricity "$1,900"Nat Gas "$1,000"
How to Frame the Analysis of Return on Investment for Energy Savings Measures"Among the practical range of investment decisions:""
"Which provides the largest “return”?""Which are in your budget range?""Which achieves the desired returns within investment timeframe?""""What non-energy benefits are driving your decision?" e.g., comfort and aesthetic benefits, health and safety, greater control over energy use, ease of selling home, enhanced pride and prestige, environmental responsibility"
"
If this, then…
If this, then…
If this, then…
Where you are
Where you’re going
Phases and Roadmaps"
If this, then…
If this, then…
Building Critical Mass:increased demand
+ stable,
qualified work force"