Indoor heat exposure is a major risk to public health, learning, and worker productivity, and the climate crisis is exacerbating these risks. Tom Phillips (Health Building Research) and Emily Higbee (Redwood Energy) summarize why indoor exposure is important, what climate and building models predict, current indoor overheating guidelines and standards, and examples of new existing buildings designed for future climates. A modeling case study is also presented to examine the energy, cost and overheating impacts of heat waves, future climate, power outages, and an optimized building design of a new single family home in California. Spoiler alert: overheating risks were substantial is all scenarios, but optimized energy-cost design alone can increase overheating problems does not necessarily ensure thermal health. Recommendations to achieve a building stock that is future proof, healthy, and resilient are included.

1. Tom Phillips and Emily Higbee
Adjusting for New ABNORMALS:
Adjusting for Extreme Heat and Outages

2. TOPICS
• Introduction and
Background
• Modeling Study Methods
& Results
• Q & A
• Overheating and Passive
Survivability Standards
and Guidelines
• Climate Adapted &
Resilient Buildings:
Examples
• Conclusions and
Recommendations
• Q & A
2
How can we adapt to extreme heat?
OR
Air Conditioning Death Spiral
Top Image: Albert, Righter & Tittman Architects

3. The New ABNORMALS (2014):
Major Shift to Extreme Temperatures
(& More Variance and Skew) is Already Occurring
3
Adapted from Wx Shift, Jan. 2020. Extreme Heat. See Also: local time series chart of temperature anomalies.
https://wxshift.com/climate-change/climate-indicators/extreme-heat.
Extreme Heat

4. Heat + Humidity
Can Kill
4
✔ #1 weather-related
killer in the U.S.
✔ Deadly Wet Bulb
temperatures are
already occurring
around the world
-- Earlier than
expected 1
✔ Radiant
temperature can
also be important
in buildings
1. NOAA, 2020
Dangerous humid heat extremes occurring decades before expected.
doi/10.1126/sciadv.aaw1838.

5. 5
Adapted from O'Lenick, et al. 2019. Urban heat and air pollution: A framework for integrating population vulnerability
and indoor exposure in health risk analyses. https://doi.org/10.1016/j.scitotenv.2019.01.002.
Framework for assessing population health risks to
climate change, extreme heat, and air pollution
Waste heat and urban heat

6. Heat Wave Exposure is Increasing in U.S.
6
Washington Post, Sept. 4. 2021.
Nearly 1 in 3 Americans experienced a weather disaster this summer.

7. WHERE
are people exposed to extreme heat ?
7
• Areas with low rates of central AC 1
– Older homes; less efficient
– Low income neighborhoods
1. Chester et al., Sept. 9, 2015
Pioritizing Cooling Infrastructure Investments for Vulnerable Southwest Populations. Study of AC status based
on property tax records regarding central air systems, etc. See also: Reyna & Chester, 2017 re: projected
electricity demand in L.A. County. https://www.nature.com/articles/ncomms14916.

8. 8
2006 California Heat Wave Mortality: Climate Zones
Adapted from: Joe et al. 2016. Mortality During a large-scale heat wave by place, demographic group, internal and external causes
of death, and building standards climate zone. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4808962/.
Total Mortality,
Relative Risk
At-Home Mortality,
Relative Risk
(66% of Deaths)

9. 9
Leahy, S., 7/6/2019. ‘Off-the-charts’ heat to affect millions in U.S. in coming decades
Within 60 years, hot days in the U.S. could be so intense that the current heat index can’t measure them.
National Geo., https://www.nationalgeographic.com/environment/2019/07/extreme-heat-to-affect-millions-of-americans/.
Interactive mapping tool: https://ucsusa.maps.arcgis.com/apps/MapSeries/index.html?appid=e4e9082a1ec343c794d27f3e12dd006d.
Dahl et al. 2019. https://iopscience.iop.org/article/10.1088/2515-7620/ab27cf.
Dangerous Heat Day Increases, 2019-2050

10. Climate Change Impacts: Cooling Demand and
Vulnerable Populations
• Increased cooling demand
(Cooling Degree Days/year) 1
– Mid-century: + > 1,000 - 1600
CDD in many regions
– Late century: + > 2,000 CDD in
many areas 2
• Energy poverty and/or
AC lacking in many areas
(blue boxes)
• Major impacts
– Health
– Energy costs
– Peak grid demand
– Grid outages
– Building design and operation
10
1. USGCRP, 2018. Fourth National Climate Assessment, Vol. 2. Fig. 14 and 19.
https://nca2018.globalchange.gov/chapter/front-matter-about/.
2. Petri & Caldeira, 2015. https://www.nature.com/articles/srep12427.
CDD Increase by Mid-Century, RCP 8.5 1

11. 11
Hundreds of thousands In Midwest facing
the prospect of boiling temperatures and
stifling humidity without electricity and AC
after thunderstorms. Aug. 2021
Climate Change, Cascading Impacts, and IEQ 1
1 Million without power for weeks
in 3 southern states after Hurricane Ida;
Heat Index over 105 F. Aug. 2021
Over 800 thousand homes in planned power
outage in California; red flag days. Oct. 2019
12 dead in Florida nursing home without
power after Hurricane Irma; 99 F inside.
Dec. 2017
11
Over 1,100 deaths and thousands
hospitalized in Pacific NW from record heat
wave. June 2021. 2,3
1. More info on cascading impacts of heat, wildfire and drought: Wilson, Aug. 5, 2021.
The Cascading Impacts of Drought and the Role Resilience Must Play. Resilient Design Institute.
2. KUOW, July 12, 2021. Nearly 800 people believed to have died in Northwest heat wave.
3. NY Times, Aug. 11, 2021. Hidden Toll of the Northwest Heat Wave: Hundreds of Extra Deaths.

12. Summary: Climate Emergency
• The Future is Now
– Extreme heat and storms
– Megadrought in Southwest is in progress
– Wildfires
– Marine heat waves
– Global climate tipping points are approaching quickly
• The Future is coming early,
and it is not distributed evenly
• Effective, large scale actions are needed immediately
12

13. Climate Adaptation Study: Objectives
• Design new single family
Zero Net Energy home in Bakersfield,
CA (2019 Title 24 baseline)
• Examine impacts of heat waves,
future climates, and power outages
on overheating and energy use
• Optimize building design
ü Energy cost (TDV and life cycle)
ü Overheating risk
ü Carbon emissions (ultimately)
13

14. Study Methods
14
Zero Carbon Hub, 2013.
Overheating in Homes: Where to Start.
• Overheating Metrics (Thermal Health)
– Discomfort Index (DI)
– Wet Bulb Globe Temperature (WBGT)
9 Foundations For Health.
Healthy Buildings Program,
Harvard School of Public Health.
https://9foundations.forhealth.org/.
Thermal Health is part of
Indoor Environmental Quality (IEQ)

15. Methods
• Time Dependent Value Energy (TDV) and Site
Energy Use
– TDV driven by peak cooling demand in California.
Current Time of Use rates were assumed.
– Site Energy per year
15
TDV image: Time of Use utility rates. GE, in CPUC, Residential Rate Reform Through 2019.
Time of Use Rates

16. Methods
§ Building Optimization
ü BeOpt 2.8.0 model in
California Title 24 mode
(NREL, free tool)
ü Optimize for TDV
ü Assess Site Energy
§ Energy and Overheating
ü CBECC Title 24 Model
16
TDV image: Time of Use utility rates. GE, in CPUC, Residential Rate Reform Through 2019.
U Curve image: Donald Peterson at Fabok, 2013. https://zsoltfabok.com/blog/2013/03/the-optimal-batch-size/.

17. Determining the Future Climate:
Looked at Heating and Cooling Demand: BFL Historical1 vs.
Cal Adapt 2 vs. Climate Analogue Cities 1
2259
3587
3894
4407 4608
2173
1337
1041
854
935
0
1000
2000
3000
4000
5000
6000
BFL 1980 - 2010 BFL 2050s Yuma AZ BFL 2090s Phoenix AZ
Heating Degree Days 65
Cooling Degree Days 65
2.0 X
17
1. NCDC, 1981-2010 Climate Normals. https://www.ncdc.noaa.gov/cdo-web/datatools/normals.
2. Cal-Adapt, 2018. Tools. Cooling and Heating Degree Days. East Bakersfield, RCP 8.5, 10 year average. https://cal-adapt.org/tools/.
1.6 X
0.4 X
0.6 X

18. Weather Station Locations for
Modeling Scenarios (T, RH, CDD)
18
Fresno (FAT),
Climate Zone 13
Bakersfield
(BFL)
Yuma:
Mid-Century
Analogue
Phoenix:
Late-Century
Analogue

19. Methods: Modeled Scenarios in CBECC
• CA Climate Zone 13, Fresno (CZ13)
– Typical historical weather,
used in building standards
• Bakersfield 2006 Heat Wave (BFL)
– Extreme historical case
– Record night and daytime
temperatures, Dry Tropical System
19
CIBSE Journal, March 2016.
• Future Climate: BFL Analogue cities
(Yuma and Phoenix, Arizona)
– Reasonable worst case (T and RH)
– Wind and solar angle don’t match BFL
• Power Outages for current and future
climates
– Near-Worst cases (no heat wave)
• Optimized Design: all scenarios

20. BeOpt Model: Optimizing Multiple Measures
20
Optimization Categories
1. Building Site
2. Walls
3. Ceilings/Roofs
4. Foundation/Floor
5. Thermal Mass
6. Windows/Doors/
Shading
7. Air Flow
8. Space Conditioning
9. Water Heating
10. Lighting
11. Appliances & Fixtures &
Schedules
12. MISC: plug loads & other
appliances
13. PV
SCREEN related categories:
Small groups, several options;
Select top 2-3 per group.
ADD PV for Site Energy need:
Test a range of sizes,
orientation, & tilt.
OPTIMIZE for TDV and
Cooling Site Energy:
No PV.

21. Examine Sensitivity and Interactions:
Window Area & TDV
21
Crossover at
lower TDV
T24 Reference
(Baseline)

22. BeOpt Example: Energy Costs vs. TDV
Title 24 Single Family box prototype, 2100 ft2, 3 BR, no PV
Energy Related Cost
($/y, Annualized)
ENERGY
COST
TDV Energy (MMBTU/y)
Minimum
Cost
22
Minimum
TDV
T24 Reference
(Baseline)

23. BeOpt Results: Select Low TDV Points
Energy Related Cost
($/y, Annualized)
TDV Energy (MMBTU/y)
23
1. Zoom In to Lowest TDV Iteration Points
(change display scales)
2. Select a Cluster of Points (up to 13)
3. Examine Measure Options of Interest

24. BeOpt Results: Low TDV Case
Example: Title 24, HPWH, No PV, plus Roof, Thermal Mass, and HVAC Options:
• Substantial reductions in TDV Energy: ~ 21 MMBTU/yr (17 %/yr)
• Annual Energy Related Cost Saving: up to ~ $140/yr (11%)
Energy Related Cost
($/yr, Annualized)
TDV Energy (MMBTU/y) 24
Low TDV
Optimum Points T24 Reference

25. BeOpt Site Energy Results:
T24 2019 Reference vs. Selected Low TDV Point
25
Site Energy
(kWh/yr)
Cooling E
Heating E
Add PV to
Match Need
• Delta, Cooling and Fan/Pump E: 618 kWh/yr (77%)
• Delta, Heating and Fan/Pump E: 756 kWh/yr (52%)
• Delta, Total Site E: 1,378 kWh/yr (16%)
Fan &
Pump E

26. Energy and Overheating Results (CBECC)
26

27. T24 Standard - Baseline
Optimized Model in
BeOpt V2.8.0.0
Window U-Value 0.3 0.17
Window SHGC 0.23 0.27
Exterior Insul. R5 R15 XPS
Attic Insul. R19 R25
Slab Insul. None 4ft, R20 exterior XPS
Overhangs None 3 ft
Vented Attic Yes No
HVAC Eff, SEER 14 22
HVAC Eff, HSPF 8.2 10
White Roof No Yes
Carpet
80% Carpet, 20%
Exposed
Exposed
Results of Energy Use Optimization for Climate Zone
13 Using BeOpt
27

28. Discomfort Index (DI)
DI = (0.5 * T dry bulb) + (0.5 * T wet bulb) 1,2
Target: > 22 °C (71.6 °F) Mild2
> 24 °C (75.2 °F) Moderate
> 28 °C (82.4 °F) Severe
Wet-Bulb Globe Temperature (WBGT)
WBGT = (0.1 T dry bulb) + (0.7 * T wet bulb) + (0.2 * T black globe) 3
Target: > 18 °C (64.4 °F) Moderate
> 23 °C (73.4 °F) Strong
> 28 °C (82.4 °F) Very Strong
Operative Temperature (OT)
OT = (T dry bulb + T radiant ) / 2
Target: > 28 °C (82.4 °F) 3
Overheating: Metrics for Public Health
28
1. Baniassadi, A. and Sailor, D. (2018)
2. Epstein, Y. and Moran, D. (2006)
3. Holmes, S., Phillips, T. and Wilson, A. (2016)

29. The importance of weather files:
TMY file vs. Historical year
29
0
20
40
60
80
100
120
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31
Outside Temperature (F)
Day
Max CZ13 Max BFL 2006
Min CZ13 Min BFL 2006
BFL Heat Wave
BFL Heat Wave
Max
Min
Max temperatures are high,
but minimum temperatures are
also high in 2006 heat wave

30. Optimized vs. Baseline Energy Use
30
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
Baseline
CZ13
Optimized
CZ13
Baseline
Bake06
Optimized
Bake06
Baseline
Yuma
Optimized
Yuma
Energy Use (kBTU)
Cooling Energy
Heating Energy
• Optimized home reduced overall energy:
• reduced cooling load for each scenario
• reduced heating load – some reduction attributed to weather file change

31. -108
426
-29
258
164
861
72
523
0 0
-5
-43
-7 -6
-200
0
200
400
600
800
1000
Year Deg. Hrs
Year
Year Deg. Hrs
Year
Year Deg. Hrs
Year
Year Deg. Hrs
Year
CZ13 Bakersfield 2006 Yuma Phoenix
Change in WBGT
Moderate
Strong
31
Optimized minus Baseline:
WBGT Hours and Degree Hours Per Year

32. Optimized minus Baseline:
WBGT Hours and
Degree Hours Per Cooling Season (May-Sep)
-77
453
-62
150
-9
507
39
408
-1 -34 -7 -6
-200
0
200
400
600
800
1000
Cooling
Season
Deg. Hrs
Cooling
Season
Cooling
Season
Deg. Hrs
Cooling
Season
Cooling
Season
Deg. Hrs
Cooling
Season
Cooling
Season
Deg. Hrs
Cooling
Season
Change in WBGT
Moderate
Strong

33. Optimized minus Baseline:
DI Hours and Degree Hours Per Year
33
-11
-34
-46
145
233
24
34
-31
-70
-17 -12
-100
-50
0
50
100
150
200
250
Year Deg. Hrs
Year
Year Deg. Hrs
Year
Year Deg. Hrs
Year
Year Deg. Hrs
Year
CZ13 Bakersfield 2006 Yuma Phoenix
Change in DI
Mild
Moderate

34. Optimized minus Baseline:
DI Hours and Degree Hours Per Cooling Season
(May-Sep)
33
-11
-34
-46
124
184
15 23
-23
-59
-17 -12
-100
-50
0
50
100
150
200
250
Cooling
Season
Deg. Hrs
Cooling
Season
Cooling
Season
Deg. Hrs
Cooling
Season
Cooling
Season
Deg. Hrs
Cooling
Season
Cooling
Season
Deg. Hrs
Cooling
Season
Change in DI
Mild
Moderate

35. Bakersfield 2006 heat wave during a power outage
Baseline vs. Optimized: DI
40
50
60
70
80
90
100
7/11 7/12 7/13 7/14 7/15 7/16 7/17 7/18 7/19 7/20 7/21 7/22 7/23 7/24 7/25 7/26 7/27 7/28 7/29
Temperature or Discomfort Index (F)
Baseline
Discomfort
Index
Opt Discomfort
Index
Simulated power outage
Mild
Moderate
Severe

36. 40
50
60
70
80
90
100
7/11 7/12 7/13 7/14 7/15 7/16 7/17 7/18 7/19 7/20 7/21 7/22 7/23 7/24 7/25 7/26 7/27 7/28 7/29
Temperature or Discomfort Index (F)
Baseline Zone
Dry Bulb (F)
Opt Zone Dry
Bulb (F)
Baseline
Discomfort
Index
Opt
Discomfort
Index
Bakersfield 2006 heat wave during a power outage
Baseline vs. Optimized: DI and zone temperature
Mild
Moderate
Severe
Simulated power outage

37. 40
50
60
70
80
90
100
7/11 7/12 7/13 7/14 7/15 7/16 7/17 7/18 7/19 7/20 7/21 7/22 7/23 7/24 7/25 7/26 7/27 7/28 7/29
Temperature or Discomfort Index (F)
Baseline
Discomfort
Index
Opt
Discomfort
Index
Phoenix during a power outage
Baseline vs. Optimized: DI
Simulated power outage
Mild
Moderate
Severe

38. 40
50
60
70
80
90
100
7/11 7/12 7/13 7/14 7/15 7/16 7/17 7/18 7/19 7/20 7/21 7/22 7/23 7/24 7/25 7/26 7/27 7/28 7/29
Temperature or Discomfort Index (F)
Baseline Zone
Dry Bulb (F)
Opt Zone Dry
Bulb (F)
Baseline
Discomfort
Index
Opt
Discomfort
Index
Phoenix during a power outage
Baseline vs. Optimized: DI and zone temperature
Simulated power outage
Mild
Moderate
Severe

39. In summary…
• Overheating:
– Reduced by TDV optimized design: for the current weather files
(TMY and Historical year), DI and WBGT were reduced
– But Increased for the Yuma model (mid century analogue)
• Optimizing for today’s weather is not optimizing for the future
weather
• Optimizing for just energy use can increase overheating. The
metric matters – including radiant temperature vs just humidity
and air temperature
• How you weight variables in your heat metric matters (radiant temp
vs wet bulb vs dry bulb)
– WBGT – overall more overheating hours, but less “very strong”
hours
– DI – overall less overheating hours, but some in the “severe”
category in power outage scenario
• Using historical weather files can give you a picture of more extreme
temperatures – but a TMY file will give you a picture of yearly energy
use.

40. Hours of Safety in Cold Climates
(Rocky Mountain Institute and Redwood Energy 2020)
Download the report here: https://rmi.org/insight/hours-of-safety-in-cold-weather/
Around two days to reach severe cold stress
temperatures for a 2009 and NZER home

41. 41
QUESTIONS OR COMMENTS ?

42. • World Health Organization (1987 and 2018):
< 24 C and > 18 C (vulnerable populations). 1
• Passive House Program:
> 25 C for < 10% (h/y), and moisture limit. 2
• CIBSE TM 59 Overheating Design Guide (UK):
– Mechanical ventilation: Operative Temperature
< 26 C for < 3% of occupied hours
– Natural Ventilation: temperature (summer occupied hours) and
annual delta T limits for bedrooms.
– Future climate scenarios recommended:, high emissions
scenarios recommended, Mid & late century. 3,4
• CIBSE TM 49 Urban Heat Island Design Guide
(UK and London Plan): 5
– Overheating risk assessment for urban heat zones.
– Design Summer Year weather file
– Hierarchy of efficiency measures, before
mechanical cooling is allowed
Overheating Standards and Guidelines:
International
42
1. WHO, 2018. Housing and Health Guidelines.
2. Passive House Institute, 2016.
Criteria for the Passive House, EnerPHit and PHI Low Energy Building Standard.
3. CIBSE, 2017: TM 59, Design methodology for the assessment of overheating in homes.
4. Diamond, S., May 22, 2017. TM 59 webinar. Inking Associates.
5. CIBSE, 2014. TM49 Design Summer Years for London. See also: ARCC Network, 2017.
Designing for Future Climate.

43. Overheating Standards and Guidelines:
International
43
1. UK Future Homes Standards, 2021. Draft standards and consultations. News:
https://www.architecture.com/knowledge-and-resources/knowledge-landing-
page/the-future-homes-standard-explained.
2. B. Cruise., March 2018. AIVC Workshop. Guideline: NZ Ministry of Education, 2017.
Designing Quality Learning Spaces – Indoor Air Quality and Thermal Comfort.
3. Top image: RIBA Journal;
• UK Draft Future Homes Standard and
Building Regulations (2021) 1
– Overheating assessment, low carbon,
and ventilation requirements
– Over 1 million homes could still suffer
from overheating (reviewers comments)
• New Zealand School Design
Guidelines: Overheating (2017) 2
– Varies by region
– < 26 C: 20 – 250 hours, < 28 C: 10 – 60
hours, 32 C max
– Design Summer Year (DSY) weather file
– Life cycle analysis, efficiency measures,
etc.

44. § LEED (2018 update) Pilot Credit: Resilient Design 2.0 2
§ Build It Green (2019): GreenPoint Rated 7.0 for CA Homes 1
§ Collaborative for High Performance National Criteria,
Climate Adaptation and Resilience credits for schools
(2019).
ü California version (2020); other states in progress (2020) 3
§ New York City (2020): Resilient Design Guidelines for city
buildings and other projects 4
§ California Dept. of General Services: climate resilience
guidelines for state buildings; Under development 5
Overheating and Adaptation Guidelines and Standards:
U.S
44
1. Wilson, A., 2018. The LEED credits are back up. Resilient Design Institute.
2. Build It Green, 2019. Version 7.0 Update, Executive Summary. Vulnerability risk assessment and reduction; passive survivability.
3. CHPS, 2020. Criteria update and webinar.
4. NY City, 2020. Reduce urban heat island; heat resilient facility; protect occupant safety (under future climates).
5. D. Burgoyne, DGS, 2021. Personal communication.

45. Overheating and Adaptation Guidelines and
Standards: Canada
§ British Columbia Housing (2019): Energy Step Code,
Overheating and External Air Quality Supplement 1
§ Langley, BC (2021): Draft GHG, thermal resiliency
(overheating), and energy equity policy) 2
ü Based on BC Guidelines
ü Modeling and Draft report planned
§ National Research Council Canada, Construction Innovation
(2021): 3
ü Overheating Risk Management Guideline and modeling results
ü Risk evaluation methodology
ü Extreme weather files
ü Heat and cold stress metric and models
45
1. BC Housing, 2019. Design Guide Supplement on Overheating and Air Quality.
2. K. Ramlu, 2021. Personal communication. More info: Langley Builder Forum Series: Passive Cooling and Step Code (June 1, 2021)
3. NRC Canada. Various reports by Laouadi et al.

46. Examples of Overheating RD&D
46

47. Improvements in Passive Survivability (Degree Hours > DI 28 C)
and Heating & Cooling ($): Phoenix, Older Building
47
Adapted from Baniassadi and Sailor, 2018.
https://doi.org/10.1016/j.buildenv.2018.01.037.
▪ Substantial improvements,
especially Passive Survivability
▪ Phoenix and Houston had similar results
▪ Cooling Energy dominated overall cost savings
% Improvement

48. Climate Adapted, Low Income Housing
in Australia
48
• Pathway to Climate Adapted and Healthy
Low Income Housing
– 10 housing typologies: single & multifamily, high and low rise
– Literature review of intervention methods for heat stress
– Heat Risk Vulnerability and Energy assessment:
baseline and interventions modeled using 2009 heat wave weather
Barnett et al., 2013. Pathway to Climate Adapted and Health Low Income Housing. CSIRO and NCCARF.

49. Climate Ready Housing in Australia
49
Outdoor and indoor Discomfort Index (DI)
values for each house type,
showing simulated performance during the
2009 heat wave event in M
Melbourne.
✔ ‘Worst case’ scenario resulted in severe heat-related health risk for 30% of the
duration of the 5-day heat wave, on average.
✔ Risk could be reduced to 17% and 13% with the cheap retrofit and expensive
retrofit, respectively.
Barnett et al., 2013. Pathway to Climate Adapted and Healthy Low Income Housing. CSIRO and NCCARF.
SFam, Post 2005, Slab,
Brick/Block walls, 3-4 BR
Multifamily
SFam, Pre 2005, Slab, Brick/
Block walls, 3-4 BR

50. Climate Ready Housing in the UK
50
• Bicester NW Eco Development
example
– 5,000 homes over next 25 years;
first in UK.
– Various cooling and heating
measures evaluated in 30 year
intervals with UKCIP future
weather data
– CIBSE and BS EN 15251
Overheating guides were used
as evaluation metric

51. Climate Ready Housing in the UK 1
51
• Suburban Neighbourhood Adaptation for a Changing
Climate (SNACC) 2
– Demonstration of climate adaptation assessment and
opportunities in built environment at neighborhood scale
– Case studies in 3 cities, 6 neighborhoods
– Modeling and monitoring for current, 2030 and 2050
scenarios
– Overheating reduced from very high levels to minimal
levels
– Cost estimates produced
– Useful community and stakeholder feedback
1. ARCC, 2017a. Design for Future Climate (D4FC).
2. ARCC, 2017b. Suburban Neighbourhood Adaptation for a Changing Climate (SNACC).

52. 52
SNACC: Example of Overheating Risk Reduction

53. Multifamily Passive House Retrofit:
Ken Soble Tower, Hamilton, Ontario 1
53
§ Designed for a changing
climate: Using 2050
temperature projections to
test thermal comfort in all
seasons.
§ Ultra-low energy use: 94%
reduction of greenhouse
gas emissions compared to
the existing building.
§ Passive resilience in case
active systems fail:
ü Stays warm in winter for up
to two days
(vs. 2 hours in a typical
building)
ü Safe heat levels in summer
for up to four days (vs. half
a day in a typical building).
1. ERA Architects. Ken Soble Tower. Completion 2020. See
also: Presentation. June 10, 2 020 .
Passive House Accelerator Happy Hour webinar.

54. • Few studies have looked at both indoor and outdoor heat mitigation vs. personal exposure and risk.
• Berlin apartment study: urban greening is not necessarily effective in reducing indoor heat hazard
– External shades were the most effective passive measure
– But several building and neighborhood measures were needed to prevent overheating (including mechanical cooling)
– Passive cooling measures did not have negative effects on outdoor hazard
• New U.S. studies: Mallen et al.., GA Tech.; Baniassadi et al., Harvard
54
Buchin et al. 2015.
doi.org/10.1016/j.enbuild.
2015.06.038
What About:
Urban Greening and Indoor Heat Exposure?

55. Designing Climate Resilient
Multifamily Buildings: British Columbia 1
§ Low and High Rise Multifamily:
New and Existing archetypes modeled
§ Thermal comfort assessed and mitigated
ü ASHRAE 55 Thermal Comfort metrics,
< 200-hours above the 80% acceptability limit
< 20 hours for vulnerable populations
ü (RCP) 8.5 scenarios for 2020s, 2050s, and 2080s
ü Heating, cooling, and GHG metrics
§ Power outages modeled
§ Incremental costs calculated: single measures & bundles
§ Design strategies recommended for each building type
55
1. RDH, 2020. Report to University of British Columbia.

56. 56
Incremental Cost and
Overheating Hours:
Existing Low Rise,
2050s RCP 8.5

57. CONCLUSIONS
57
• Modeling and measurement tools
are available to
ü assess and mitigate overheating and energy
impacts of climate change
ü to keep buildings healthy and resilient
(survivable).
• Momentum to address this problem is
growing in N. America
ü Market advantage (health & comfort)
ü Reduced liability (due diligence)
ü Grid benefits (peak and average demand)
ü Reduced energy cost
ü Reduced GHGs, air pollution, waste heat
ü Improved equity, human productivity, and
mental health
• Some data and research needs exist
IR camera finds thermal leaks
McDonald and McCormack, 2021

58. RECOMMENDATIONS
Provide and promote future proof, healthy, and resilient
buildings that adapt to and mitigate climate change,
especially for extreme heat – at local, state & national levels
✔ Assess climate vulnerability to extreme heat using future weather
files, and design for full life cycle optimization and phasing.
✔ Include passive cooling measures in retrofit and new construction
programs, targeting heat vulnerable populations.
✔ Update building standards and design guidelines now.
✔ Educate, integrate, and train building, planning, & health
professionals (Health in All Policies).
✔ Accelerate market demand through improved financing, incentives,
demonstrations, and marketing for future proof, resilient buildings.
58

59. Contact Information
Tom Phillips, Healthy Building Research
tjp835@gmail.com
Emily Higbee, Redwood Energy,
higbee.emily@gmail.com 59
Thought For the Day:
BE PREPARED
for Extreme
Conditions
QUESTIONS OR COMMENTS ?

60. THANK
YOU!
Join the conversation:
#2021EEBASummit #eeba #goeeba

61. BONUS SLIDES

62. Emerging Trends
• Assessment & mitigation of overheating for current and future
climate are gaining steam, especially in Canada. Standards and
guidelines are growing slowly.
• Multi-objective modeling: used in some commercial buildings
• Climate resilience plus low income weatherization is a great
opportunity. Study underway by Boston University.
• Research studies of overheating and passive survivability are
growing rapidly around the world
• Future weather files: good resources, including urban heat
• Extreme weather files: growing body of R&D; no consensus yet
• Building stock data: spotty growth. ORNL data base for US may be
useful.
• Assessment of waste heat effects on indoor and outdoor
environment is growing
• HVAC and other equipment not designed for extreme heat
• Unintended consequences: Overheating risk from added insulation or
thermal mass
62

63. ✴ PG&E considering the development of future weather files. 1
✴ CALMAC published typical 10-year weather files and annual weather
files up to 2018 for all major cities are now available. 2
✴ CEC Cal-Adapt climate tools update is proposing to include hourly
weather data & projections. 3
✴ CEC is planning research for updating the scenarios and analyses for
California's Fifth Climate Change Assessment. 4
✴ California PUC will address strategies and guidance for
climate adaptation for electric and natural gas utilities. 4
Overheating and Adaptation Guidelines and Standards:
California (Jan. 2020)
63
1. J. Huang, White Box Technologies. Personal communication, October 17, 2019.
2. CALMAC, 2019. California Weather Files . 13 climate zones of California. http://www.calmac.org/weather.asp.
3. CEC, Dec. 18, 2019. Staff Workshop - Hourly Temperature Data on Cal-Adapt. See Docket Log for presentations and comments.
4. CEC, Dec. 16, 2019. Forthcoming Solicitation Regarding Climate Scenarios and Analyses to Support Electricity Sector Vulnerability
Assessment and Resilient Planning.
https://www.energy.ca.gov/event/workshop/2019-12/staff-workshop-forthcoming-solicitation-regarding-climate-scenarios-and.
5. CPUC, Sep. 16, 2019. Rulemaking R.18-04-019. Order and updates at https://apps.cpuc.ca.gov/apex/f?p=401:59:0::. News article:
www.cpuc.ca.gov/.../CPUC_Website/.../Filings%20newsletter%202018-05.pdf.

64. Bakersfield Future Climate, 2080s: Yuma AZ region
(From 1960-90 to 2080s, RCP 8.5, 4 seasons)
64
Phys.org, 2/12/19. Climate of North American cities will shift hundreds of miles in one generation.
Based on projections for 12 climate parameters across 4 seasons. Interactive map at http://www.umces.edu/futureurbanclimates.
Fitzpatrick et al., 2019. https://doi.org/10.1038/s41467-019-08540-3

65. Site Design: T24 vs. BeOpt Low TDV Example
T24 Reference Point:
Windows 105 SF/side, 20% CFA
HPWH, etc.
65
BeOpt Upgrades:
Windows 50 SF/side, triple glazing,
Eaves, overhangs, cool roof,
Insulation, air leakage, etc.

66. Building Parameters: Screen Various Options
Example: Exterior Slab Insulation
66

67. Screening Small Groups of Similar Measures Together:
e.g., Interactions Among Windows, Airflow, Building Orientation
67

68. Indoor Heat Stress: WBGT vs. Thermal Comfort Standards
68
• Healthy, acclimatized adult workers.
• 25 % chance of exceeding WBGT targets: 28 C target for light activity (200 kcal/h, Blue lines)
and 31 C for resting (100 kcal/h, Red lines)
• Wind speed (v): Baseline = 0.3 m/s. Adjusted = 3.5 m/s.+
• Radiant temperature (Tg): Baseline = outdoor dry bulb temperature. Adjusted: add 5 C.
Indoor Dry Bulb Air Temperature (C)
Holmes et al., 2016.
Overheating and passive
habitability: indoor health
and heat indices.

69. BeOpt Results: Examine Points for
Cooling and Total Site Energy Use
69
Zoom In to Low TDV Iteration Points
(change display scales)
Select a Cluster of Points (up to 13)
Total Site Energy
(kWh/yr)
Cooling
Energy
(kWh/yr)
Iteration Number

70. Examine Interactions via Sensitivity Display:
Slab Insulation & Site Energy
70
Crossover at
higher Site E

71. • 114 U.S. cities (5 shown), elderly Medicare patients
– Apparent Temperature (T & RH), 1992 - 2006 warm seasons
• Hospitalization for 3 major health effect types
– Adjusted for outdoor ozone
– Lag effects observed up to 8 days
• Non-linear effects
– Varies among cities (L.A. is yellow line)
– Biggest increase is 30% increase in Renal cases in L.A. (kidney disease)
– Additional effect of heat wave observed (6+ days over 95 %ile)
Heat and Health: Hospitalization (% Increase)
71
Gronlund et al., 2014.
Heat, heat waves, and hospital admissions among the elderly in the United States, 1992-2006.
L.A.

72. Heat Mortality & Morbidity: Maricopa Co., AZ
72
Daily Maximum OUTDOOR Temperature (deg C)
Petitti et al. 2016. Multiple Trigger Points for Quantifying Heat-Health Impacts:
New Evidence from a Hot Climate. https://doi.org/10.1289/ehp.1409119.
IRT: lowest temperature at which there is a
larger impact on the health event than what is
expected under optimal weather conditions.

73. Heat Mortality Effects: Indoor, Non-Linear
Model Performs Better 1
73
OUTDOOR, BERLIN MFAM
INDOOR, BERLIN MFAM
Buchin et al., 2014. Proceedings, 3rd IC2UHI. Venice.

74. • Increases at Lag 0 - 7 days: (delayed and/or cumulative effect)
– Renal (G): 50 - 90 % increase in some cities
– Respiratory (H): 30 - 40 % increase in some cities
• Increases start at ~ 22 C (72 F) Apparent Temperature
– Even at Lag 0 day (L.A. is yellow line)
Heat and Health: Hospitalizations (Pt. 2)
74

75. Discomfort Index (DI, °C) in SFam Archetype
New
75
Adapted from: Baniassadi and Sailor, 2018.
Synergies and trade-offs between energy efficiency
and resiliency to extreme heat – A case study.
https://doi.org/10.1016/j.buildenv.2018.01.037.
▪ Heat Wave (95 %ile DBT,
TMY-3 weather file)
▪ 3-Day Power Outage
▪ Houston vs. Phoenix
(Low T, hi RH vs.
High T, low RH)
▪ Old vs. New Construction:
modeled in EnergyPLus
▪ Old Construction:
56 & 78 degree-hours
Severe DI >°28 C
(HOU & PHX)
▪ New Construction cooler:
barely > 28 C
▪ Maximum DI’s of cities were
similar, but Minimum DI’s
lower in Phoenix

76. New and Existing Buildings:
Already Overheating
• New CA Single
Family homes:
19% “too hot”
(Offermann, 2005)
• NYC apartments:
24/7 Heat Waves in
• U.S. schools closing
during heat waves
• Arizona indoor heat
deaths
76
Harlem Heat Study
Maricopa Co. AZ,
2016-2018.
Over 100 Indoor
Heat Deaths;
over 100 F in half
of homes

77. Hotter, Longer, and More Frequent Heat Waves:
Sacramento, > 103.9 F (98% ile Max Temperature)
77
CEC, 2017. Cal-Adapt 2.0 Beta, Extreme Heat Tool. RCP 8.5, Sacramento.
> 107.3 & 110
F
Longest Heat Wave (avg.):
1961-1990, 2 days
2070-2099, 10 days

78. WHERE?
Extreme Heat Increases Everywhere –
Even with a 1.5 C increase 1
78
Mean
Temperature
Minimum
Nighttime
Temperature
Max
Daily
Temperature
25th %ile 75th %ile
1. Seneviratne et al., 2018.
Modeling with RCP 8.5.
CHANGE BY
2100

79. Heat Index > 100 F in Bakersfield: 1971-2099
(Days per Year)
79
Climate Toolbox, 2020. Boxplots. Results of 20 models in CMIP5 2.5 mi2 future climate results, Bakersfield, CA.
https://climatetoolbox.org/tool/future-boxplots.

80. Increasing Minimum Temperature in
Bakersfield: Summers, 1971-2099
80
Climate Toolbox, 2020. Boxplots. Results of 20 models in CMIP5 2.5 mi2 future climate results, Bakersfield, CA.
https://climatetoolbox.org/tool/future-boxplots.

81. WHY
Climate Adaptation and Resilience for Buildings ?
81

82. • Current and projected prevalence in the U.S., e.g.: 1
– Elderly: 8% in 2010, 20% in 2050.
Many in nursing homes, assisted living
– Obesity in adults: 36%, regional hot spots
– Diabetic adults: 8%, up to 28% by 2050
– Hypertensive adults: 33%; 71% in elderly
– Social isolation, adults: 17% in women, 21% in men
– Low income: 15%
– Little / no home insulation: 21%
• Many people have co-morbidities
• Demographics + Health Risks + Climate Change =
Perfect storm is brewing for public health and housing
Vulnerable Populations: Growing Rapidly
82
1. Holmes, Phillips, and Wilson, 2016. Overheating and passive habitability: indoor health and heat indices.
https://www.tandfonline.com/doi/abs/10.1080/09613218.2015.1033875?journalCode=rbri20.
See CDC for updates on chronic diseases.

83. Time to Reach 90 °F (modeled hours): Los Angeles
83
Day: 0 1 2 3 4
Building Type & Vintage
Mostly
MFam,
pre 90s, &
pre 60s.
Mobile
homes
not
included.

84. U.S. Climate Shift Southward
(From 1960-90 to 2080s, RCP 8.5, 4 seasons)
84
Phys.org, 2/12/19. Climate of North American cities will shift hundreds of miles in one generation.
Based on projections for 12 climate parameters across 4 seasons. Interactive map at http://www.umces.edu/futureurbanclimates.
Fitzpatrick et al., 2019. https://doi.org/10.1038/s41467-019-08540-3