Shawna henderson_nshba_trc_oct2010
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Deep energy retrofits aim to reduce energy use by 50-90% compared to standard retrofits which aim for 20-30% reductions. A deep retrofit may involve upgrading insulation levels in walls, attics, basements, and installing more efficient windows and doors. High performance retrofits are challenging due to the need for qualified contractors and financing options. Meeting hot water needs can be a bigger challenge than space heating for highly efficient homes. Location and house type can impact the feasibility of achieving net-zero energy use.
Shawna henderson_nshba_trc_oct2010
- 1. Deep Energy Retrofits Energy Efficiency programs aim for a 20 to 30% " water heating needs." reduction in space and A deep energy reduction aims for 50 to 90%." Shawna Henderson, CEO" Bfreehomes Design Ltd."
- 2. Approaching Net Zero Energy in Existing Houses" 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?"
- 3. 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"
- 4. 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?" 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 "
- 5. 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 Ceiling Main Walls Exposed Floors Below Grade Walls Slab Vancouver 10.6 (60) 7.0 (40) 7.0 (40) 7.0 (40) 1.8 (10) Calgary Toronto 14.4 (80) 10.6 (60) 10.6 (60) 7.0 (40) 10.6 (60) 7.0 (40) 7.0 (40) 1.8(10) 7.0 (40) 1.8 (10) Montreal 14.4 (80) 10.6 (60) 10.6 (60) 7.0 (40) 1.8 (10) Halifax Whitehorse 10.6 (60) 14.4 (80) 7.0 (40) 10.6 (60) 7.0 (40) 10.6 (60) 7.0 (40) 1.8 (10) 7.0 (40) 1.8 (10)
- 6. Assumptions we can challenge" Canadian houses need full-size, central heating systems" The diminishing returns on insulation limit thermal envelope improvements" " Windows have crappy performance" Energy availability and low prices will remain stable, so it’s business as usual"
- 8. The Envelope, Please!" Focus on draftproofing, then insulation" "foundation up" Doors, windows replace/repair/retrofit" " Lower envelope requirements = " Lower energy needs = " smaller space conditioning requirements"
- 9. Ligh4ng 5% Shift the relationships between purposes and energy use" " As Is Appliances 13% Water 17% DER with Solar Thermal Space 65% Ligh4ng 13% Space 33% Conven*onal Ligh4ng 6% Appliances 46% Appliances 16% Water 21% Space 57% Water 8%
- 10. Meeting DHW load becomes becomes bigger challenge than space heating as envelope improves" Energy Use Comparison 400 350 300 250 50% reduc4on Ligh4ng 200 Appliances Water 150 80% reduc4on Space 100 50 0 As Is Conven4onal DER with solar
- 11. #1: get rid of water problems"
- 12. #2: don’t invite them back" 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"
- 13. Above-Grade Insulation " ‘flash and batt’ interior strap-out or standoff " Min. 2” layer of 2lb foam for air barrier " !!! HEADER ALERT!!! " "
- 14. 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
- 15. OMG!!! BFFL!!! The Whole House Drainage Plane "
- 16. Outies Rule!" Extended ½” ply window bucks flush with 3 to 4 inches of exterior foam" Illustra4on from www.buildingscience.com Another Bestie:" Pan Flashings" Innies:" Window is in same plane as original wall" Pictures from BSI presentation at ACI New England 2010: Windows: i.e., The Holes in Your Wall • Simpler drainage plane connections and geometry" • Lower cost (extra trim is interior material – we use drywall)" • Similar appearance to original, tie in w/neighbourhood" • 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?"
- 17. Comfort Envelope = Thermal Envelope " 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"
- 18. Window Comfort 1 " 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?"
- 19. Window Comfort 2 " 4 factors:" Air Temperature" Mean Radiant Temperature" Relative Humidity" Air Movement" 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!" Air Movement/" Relative Humidity" Mean Radiant Temp/" Air Temperature"
- 20. Thermal/Comfort Envelope " 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."
- 21. Oh, ya, mechanicals… " Two of each:" " 60% efficient, 120k Btu oil boiler" " 80 gal. electric water heaters + indirect tank, uninsulated in unconditioned space" … to this" (reasonable facsimile of system) " From this … " 97% efficient, 50k Btu natural gas condensing boiler augmenting solar thermal system " DHW and space heating delivered via dual-coil, 120 gallon storage tank"
- 22. From monster cast iron rads EVERYWHERE to infloor radiant at 12 and 16 inch o/c"
- 23. From high-temp hydronic baseboards EVERYWHERE to a few wall-hung low-temp rads"
- 24. 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?"
- 25. 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"
- 26. Value of Non-Energy Benefits…" …to utility Transmission /distribution savings Peak load restrictions Reductions in arrears and late payments/write offs/bad debt Reduced regulatory costs and discount payments Reduced emergency service calls" …to society Economic impacts (job creation/tax revenue) Improved housing stock/preservation Emission/environmental impacts Health and safety benefits Water and wastewater savings" " What do all of these benefits have in common? " They can be quantified. "
- 27. 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."
- 28. 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"
- 29. EE Investment/Energy Costs " Conventional: $22k" Oil " "$8,100" Electricity "$7,300" Nat Gas "$4,000" Oil " "$5,100" Electricity "$4,600" Nat Gas "$2,600" Deep Energy Retrofit: $37k" DER w/solar combi: $52k" Oil " "$2,100" Electricity "$1,900" Nat Gas "$1,000"
- 30. 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" "
- 31. Phases and Roadmaps " If this, then… Where you’re going If this, then… Where you are If this, then…
- 32. Building Critical Mass: If this, then… increased demand + stable, qualified work force " If this, then…