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Demystifying Home Energy Use
May 21, 2015Central Brevard Library
Cocoa, Florida
Janet McIlvaine and David BealBuildings Research Division
Research [email protected] [email protected]
(Please include “home energy” in your subject line.)
FSEC established in 1975 by Florida Legislature 30 years of energy efficiency research for Homes
and Buildings for Florida Certifications, Training, & K-12 STEM Teachers
Florida Solar Energy Center
(FSEC)
1679 Clearlake Rd Cocoa, FL 32922Corner of Michigan & Clearlake on the UCF Cocoa
Campus
Measured building energy use savings Develop guidelines for contractors Does it work in the real world?
Real houses and full scale residential & commercial labs
Florida Solar Energy Center
Buildings Research Scope
Florida Solar Energy CenterBuildings Research Scope
Investigate How Houses Use Energy Goal: Minimize Energy Use Without
Sacrificing Health, Safety, Durability, or Comfort
Do no harm Combustion safety caution
Researchers Conclude: It’s Complicated!Use free resources at www.fpl.com and consult a RESNET certified home energy rater and/or an Energy Star certified heating & cooling contractor
$1,885Annually
$0Annually
Florida Solar Energy Center
Buildings Research Basics
Department of Energy Goal: zero energy homes Produced power ≥ Needed power - annually Maintain or improve occupant safety and
comfort, indoor air quality, & building durability
Florida Solar Energy Center
Zero Energy Home Basics
Off-the-grid or grid-tied (above) zero energy houses offset power use with power produced by solar electric panels. Excess sold to the utility.
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Is Zero Energy practical for new homes? Yes - see case studies Engineered set of improvements & detailing to prevent failures
Zero Energy by design: HERS Index score ≤ 0 (with Solar) HERS Index score = ~55 (w/o Solar)
Florida Solar Energy Center
Zero Energy New Homes
This Home Without Solar 55
Typicalnew FLhome
Is Zero Energy practical for existing homes? In research realm Carefully selected measures Time line complications Comprehensive plan to prevent failures
Florida Solar Energy Center
Zero Energy Existing Homes
Private Residence, 1959
Cocoa Beach, FL
Pre $754 Post $557 $377 v $278$377 v $278$377 v $278
Florida Solar Energy Center
Typical Projected Annual Energy Use for 70 Florida Homes
Retrofit Status
CondArea Ft2
Average
Day kWh
Average Day $
Average
Month $
Average
Year $
Average
Year $/Ft2
Before 1,365 ft2
40 kWh $ 5.16 $ 157 $ 1,885 $1.42
After 1,365 ft2
29 kWh $ 3.82 $ 116 $ 1,394 $1.05
Daily Average Use = 43 kWh, $5.16 = $154 Monthly
= $1,883 Annually = $1.79 per square foot/year
1050 ft2 , 3 BR, slab on grade, concrete block, ~1993 construction
Typical Residential Energy Use in Florida
Heating & Cooling 40.7%
Other 19.6%
Refrigerator 7.9%
Dryer 8.6%
Range 4.4% Water Heating 18.7%
Typical Residential Energy Use in Florida
Daily Average Use = 39.1 kWh, $4.69 = $141 Monthly
= $1,712 Annually = $1.05 per square foot/year
1627 ft2 , 3 BR, slab on grade, concrete block, 2003 construction
Typical Residential Measured Energy Use
Year Cond
Area
Ft2
AvgDay kWh
AvgDay
$
AvgMont
h$
AvgYear
$
AvgYear/Ft2
$
1993 1,050
43 $5.16 $154 $1,883
$1.79
2003 1,627
39.1 $4.69 $141 $1,712
$1.05
Building America Partnership for Improved Residential Construction
Decade Average Pre-retrofit HERS Index Scores
1970’s 132
1990’s 112
2000’s 107
1960’s 150 1980’s 125
15
ZeroEnergy
New HomeBefore Solar
Building America Partnership for Improved Residential Construction
HERS Index Examples
2000’s = 107
16
1960’s = 150
Solar Ready = 55Zero Energy = -6
How Low Can Existing Homes Go? Cost Effectively!
70 House Field Study of “Deep Energy Retrofits”30% HERS Index Improvement Goal
Nearly All Improvements Packages Predicted Positive Cash Flow
Partner map
Partnerships Map: http://goo.gl/5KnTau
Building America Partnership for Improved Residential Construction
Pre- & Post-Retrofit HERS IndicesExisting homes made as good as new!
18
TypicalNew FloridaHomes
Building America Partnership for Improved Residential Construction
Wide Variation in HERS Index Score Among Houses of Similar Age
TypicalNew FloridaHomes
Building America Partnership for Improved Residential Construction
• Existing Unoccupied Homes in Palm Bay, Florida• Pre-retrofit HERS Index score = 121• HERS Index score = 65 (46% improvement)
Florida Solar Energy CenterComprehensive Renovation
Foreclosed Home Rehab, 1973Palm Bay, FL
Building America Partnership for Improved Residential Construction
• Energy Retrofit Package– Replacement HVAC equipment – SEER 15, HSPF 8.5– Increase ceiling insulation to R38– Air sealing – ACH50 = 7.44 (average new 6)– Duct replacement & sealing – Qn = 0.07– Replacement Windows (U = 0.32, SHGC = 0.28)– Energy Star refrigerator– Replacement Water heater EF = 0.92– 90% CFL or Fluorescent Tube Lighting – Replacement Lighter shingle color– Efficient ceiling fans – 130W at medium speed
Florida Solar Energy CenterComprehensive Renovation
Building America Partnership for Improved Residential Construction
• Energy Retrofit Package– Total cost for energy related improvements = ~$24,000– INCREMENTAL cost =~$5,000 (out of $24,000)
Florida Solar Energy CenterComprehensive Renovation
% HERS Index Improvement 46%
Incremental Improvement Costs $5,013Additional Monthly Mortgage +$34
Monthly Energy Savings -$49Monthly Cash Flow +$15
Simple Payback (years) 8
Building America Partnership for Improved Residential Construction
70 House Deep Retrofit Field Study 13 Most Prevalent Key Strategies
13 Key Efficiency Strategies in Order of Prevalence
Deep Retrofits (n = 46)
Non-Deep Retrofits (n
= 24)
All Houses(n = 70)
1. At Replacement, Higher HVAC efficiency 96% 71% 87%
2. Additional ceiling insulation 93% 63% 83%
3. Whole-house air sealing (Reduced ACH50) 92% 77% 88%
4. Air distribution system sealing (reduced Qn,out) 86% 68% 80%5. At Replacement, Low-e windows or 6. Apply high perf. film
80% 46% 67%
7. At Replacement, ENERGY STAR® refrigerator 76% 71% 74%
8. At Replacement, Highest efficiency tank type water heater 70% 38% 59%
9. At Replacement, 30% more fluorescent fixtures/bulbs 52% 42% 49%
10. Programmable thermostat 48% 42% 46%
11. At Replacement, R-6 ducts 39% 13% 30%
12. At Replacement, Higher reflectivity exterior wall color 30% 8% 23%
13. At Replacement, Higher reflectivity roof shingles 30% 13% 24%
14. At Replacement, Higher efficiency ceiling fan(s) 15% 13% 14%
Building America Partnership for Improved Residential Construction
Cost Effective Efficiency Enhancements and Replacements
• Anytime, low-cost measures: • Behavior Modification• House sealing* (92% of the deep retrofits) • Duct sealing* (86%)• CFLs (52% increased CFL count by 30%+)• Programmable thermostat (48%)• New: Insulate hot water heater* & accessible hot water pipes
• Anytime, moderate-cost measures• Insulate ceiling to R-38 (93% insulated to R-30+)
*Heed combustion safety cautions. Contact Janet McIlvaine, 321-638-1434
24
Building America Partnership for Improved Residential Construction
• At replacement, no/low cost measures: (Higher efficiency choices at change-out)
• ENERGY STAR® appliances (76% of the deep retrofits)• Higher efficiency water heater (EF ≥ 0.92) (70%)
– Consider much bigger savings with heat pump water heater or solar or instantaneous gas
• Choose higher insulated (R-6) duct work (39%)• Choose lighter exterior colors when time to reroof (30%)• ...or paint exterior (30%)• ENERGY STAR® fans (15%)
25
Cost Effective Efficiency Enhancements and Replacements
Building America Partnership for Improved Residential Construction
• At replacement, moderate/high cost measures: (Higher efficiency choices at change-out)
• ≥15 SEER AC; Heat pump in Central FL (96% of the deep retrofits replaced ACs, 95% of those SEER ≥ 15)
• ENERGY STAR® windows or apply low SHGC film (80%)(SHGC ≤ 0.27; U-value ≤ 0.60)
26
Cost Effective Efficiency Enhancements and Replacements
Building America Partnership for Improved Residential Construction
• Behavior Modification– Maintain your central air conditioner
• Keep filter clean• Set fan to “auto” instead of “on”
– Set thermostat as high as you are comfortable and maintain ~5° higher when not at home
• Every 1° cooler = Approx 6% cooling energy
– Turn off ceiling fans when occupants are not present • (1 fan continuous oper. = approx $7/month)
– When washing in hot water, adjust the load selector to match the actual size of the load.
– Keep the lint filter in your dryer clean
Cost Effective Efficiency Enhancements and Replacements