SolarSmart

1
Introducing
SolarSmart
The intelligent approach to energy-saving roof
systems
2
What is SolarSmart?
An approach to energy-savings that

• Uses Cool Roof Calculator developed by U.S.
  Department of Energy / Oak Ridge National
  Laboratory
• Determines energy-savings options based on local
  climate and current energy costs
• Compares the contribution of roof reflectivity
  and insulation to energy-savings
• Answers the question, What roof will save me the
  most energy dollars?

3
The Basics of SolarSmart
Roofs save (or lose) energy two ways
1. The roof surface will either reflect or absorb
heat from the suns rays
2. Roof insulation will retard transfer of heat
to / from the building interior
4
The Basics of SolarSmart
The reflectivity / insulation trade-off
Because the roof surface will either reflect or
absorb heat from the suns rays .
a highly reflective roof that reduces cooling
costs in the summer will also raise heating costs
in the winter.
5
The Basics of SolarSmart
The reflectivity / insulation trade-off
Cool (reflective) coatings and insulation may
reduce a buildings heat gain by the same amount
during the summer, but their effects in winter
are very different. Cool coatings reflect away
the warming rays of the sun in both summer and
winter, making the building slightly colder in
winter. Insulating a roof reduces the heat flow
through the roof all year, keeping a building
cooler in summer and warmer in winter.
Dr. Lisa Gartland, Lawrence Berkley National
Laboratory From Truths and Myths About Cool
Roof Coating Systems (Italics Added)
6
The Basics of SolarSmart
The SolarSmart answer
Select the optimal balance of insulation and roof
surface right for your climate!
7
SolarSmart helps you.
SolarSmart

• Choose the type of roofing system you prefer
• Determine your SolarSmart climate zone
• Adjust the roofing system for optimal
  energy-savings

8
Step 1 Choose your roofing system.
Low-Reflective (5)
Semi-Reflective (20)
High-Reflective (50)

• Black Single-Ply
• Smooth Surface Asphalt

• Ballasted Single-Ply
• Gravel-Surfaced Asphalt
• Mineral-Surfaced Asphalt
• Grey or Tan Single-Ply

• White Single-Ply
• Reflective Coating over
• Other Single-Ply
• Smooth Asphalt
• Mineral-Surfaced Asphalt

9
Step 2 Determine long-term roof reflectivity
90 80 70 60 50 40 30 20 10 0
White single-ply membranes
High-Reflective (50)
Reflectivity ()
Non-white2, mineral surfaced, ballasted membranes
Semi-Reflective (20)
Black single-ply and asphalt membranes
Low-Reflective (5)
Exposure (Years)
Roof Reflectance After Field Exposure1 Exposure
on Oak Ridge Laboratories Envelope Systems
Research Apparatus (ESRA)

• NOTES
• Measurements taken prior to cleaning. In most
  cases, membranes can be restored to within 10 of
  original reflectivity with cleaning.
• Grey or tan.

10
Step 3 Determine your SolarSmart Climate Zone
Zone 1
Zone 3
Zone 2
Seattle
Albany
Portland
Portland
Minneapolis
Boise
Buffalo
Detroit
Milwaukee
Boston
San Francisco
Cheyenne
Reno
Omaha
Salt Lake City
NYC
Pittsburgh
Cleveland
Chicago
Indianapolis
Baltimore
Las Vegas
Denver
Richmond
Los Angeles
Kansas City
Louisville
St. Louis
Charlotte
Albuquerque
Ok. City
Zone 4
Nashville
Little Rock
Atlanta
Phoenix
Dallas
Birmingham
Jacksonville
Zone 6
Tampa
New Orleans
Houston
San Antonio
Miami
Zone 5
Zones based on similar combined heating
cooling loads using DOE Cool Roof Calculator and
assuming 0.075 / Kwh electricity cost, 2.5 air
conditioning COP, 0.85 / Therm natural gas
pricing, and 85 heating system efficiency.
Calculations assume that the building will be
heated in winter and cooled in summer in
accordance with ASHRAE 90.1 guidelines.
11
SolarSmart Climate Zones
Minimum Insulation Value
Insulation / Reflectivity Trade-Off
Highly reflective roofs used in this zone may
actually increase energy costs. Increased heating
costs due to solar heat loss in the winter may
exceed cooling cost savings in the
summer. Increasing insulation for a
non-reflective or semi-reflective roof in these
zones may offer a cost-effective alternative to a
reflective roof. Increased insulation in this
zone on a non-reflective roof will likely be more
costly than a semi-reflective or reflective roof.
ASHRAE 90.1 guidelines typically recommend roof
insulation between R-20 and R-25. ASHRAE 90.1
guidelines typically recommend roof insulation
between R-17 and R-20. ASHRAE 90.1 guidelines
typically recommend roof insulation between R-15
and R-17.
Zone 1
Zone 2
Zone 3
Zone 4
Zone 5
Zone 6
Zones based on similar combined heating
cooling loads using DOE Cool Roof Calculator and
assuming 0.075 / Kwh electricity cost, 2.5 air
conditioning COP, 0.85 / Therm natural gas
pricing, and 85 heating system efficiency.
Calculations assume that the building will be
heated in winter and cooled in summer in
accordance with ASHRAE 90.1 guidelines.
12
Step 4 Select SolarSmart Adjusted Insulation
Values
All systems shown for each zone generate the same
energy savings.
Roof Surface
SolarSmart Climate Zone
Low-Reflective (5)
Semi-Reflective (20)
High-Reflective (50)
Zone 1
Use R-25 Insulation
Use R-25 Insulation
Not Recommended
Zone 2
Use R-22.5 Insulation
Use R-22.5 Insulation
Use R-20 Insulation
Zone 3
Use R-25 Insulation
Use R-22.5 Insulation
Use R-20 Insulation
Zone 4
Use R-27.5 Insulation
Use R-25 Insulation
Use R-20 Insulation
Zone 5
Use R-30 Insulation
Use R-27.5 Insulation
Use R-20 Insulation
Zone 6
Use R-22.5 Insulation
Use R-15 Insulation
Use R-25 Insulation
Source DOE Cool Roof Calculator, using 0.075 /
Kwh electricity cost, 2.5 air conditioning COP,
0.85 / Therm natural gas pricing, 85 heating
system efficiency, R20 roof insulation.
Comparison of EnergyStar-approved reflective roof
cover (50 3-year reflectivity) and and a typical
semi-reflective roof (20 reflectivity) versus a
non-reflective roof (5 reflectivity).
Calculation assumes that the building will be
heated in winter and cooled in summer in
accordance with ASHRAE 90. 1 guidelines.
13
R-Value Needed To Obtain The Same Energy
Savings (Heated Cooled Buildings)
High-Reflective Roof
Low-Reflective Roof
Semi-Reflective Roof
City
Phoenix Dallas Atlanta Nashville Baltimore Chicago
Minneapolis Seattle
R15 R20 R20 R20 R20 R20 R25 R20
R24 R29 R27 R25 R22 R21 R23 R18
R20 R25 R24 R23 R21 R20 R24 R19
Equivalent energy savings calculated using DOE
Cool Roof Calculator and assuming 0.075 / Kwh
electricity cost, 2.5 air conditioning COP, 0.85
/ Therm natural gas pricing, and 85 heating
system efficiency. Insulation values rounded to
nearest 2.5 R. Minimum insulation values for each
city derived from ASHRAE 90.1. Building assumed
to be heated in winter and cooled in summer.
14
What about buildings that are heated only?
R-Value Needed To Obtain The Same Energy
Savings (Heated-Only Buildings)
High-Reflective Roof
Low-Reflective Roof
Semi-Reflective Roof
City
Phoenix Dallas Atlanta Nashville Baltimore Chicago
Minneapolis Seattle
R16 R21 R21 R21 R22 R22 R23 R23
R15 R20 R20 R20 R20 R20 R20 R20
R15 R20 R20 R20 R21 R21 R21 R21
Equivalent energy savings calculated using DOE
Cool Roof Calculator and assuming 0.075 / Kwh
electricity cost, 2.5 air conditioning COP, 0.85
/ Therm natural gas pricing, and 85 heating
system efficiency. Insulation values rounded to
nearest 2.5 R. Minimum insulation values for each
city derived from ASHRAE 90.1.
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SolarSmart Check it out for yourself
Step 1 Go to www.ornl.gov/roofswalls/facts/CoolR
oofCalc1_1.htm
2. Select the state nearest city. 3. Select the
R-Value of the roof. (ASHRAE recommends R15 to
R20) 4. Enter solar reflectance . For a
high-reflective roof, use 50 (EnergyStar 3-year
aged criterion) 5. Enter Infrared Emittance. Use
90 for single-ply and asphalt roofs. 6. Enter
local cost of electricity. (Current US average is
0.075 / KWh for commercial / industrial
customers) 7. Enter A/C Coefficient of
Performance (Typically between 2.0 and 3.0 for
older equipment) 8. Enter local cost of heating
fuel. (Current US average per Therm is 0.75 for
natural gas, 0.85 for heating oil) 9. Enter
heating system efficiency. (Typically around 0.80
for gas-fired furnaces)
My State


My City


My Proposed Roof

R
-
Value


50
Solar reflectance, SR



90
Infrared emittance, IE


My Energy Costs and Equipment Efficiencies
Summertime cost of electricity /KWh
0.075


2.5
Air conditioner efficiency (COP)


.75
Heating fuel cost /Therm
.80
Heating system efficiency fraction


Net Savings /ft2 per year
Cooling Savings /ft2 per year

The Calculator will then automatically determine
a) The net energy savings for a reflective
roof (as compared to a non-reflective roof) b)
the adjusted R-value for a non-reflective roof.

Heating Savings (Penalty) /ft2 per year

Insulation in Black Roof to Yield Same Annual
Savings
Upgrade from R- to R-
16
What SolarSmart says about roofs energy savings

• Using reflective roofs in the Northern U.S. and
  Canada may increase overall energy costs,
  especially for buildings that are heated only, by
  reducing solar heat gain in the winter.
• A non-reflective or semi-reflective roof can be
  just as energy-efficient as a reflective roof
  simply by adding roof insulation. And, in many
  areas of North America, the amount of insulation
  needed to offset a heat reflective coating is
  relatively small.
• Even in warm climates, insulation can offer a
  energy trade-off that always should be
  investigated.

Notes

• The calculated energy savings for reflective
  roofs is based on the assumption that the
  reflective roof will be cleaned periodically in
  order to maintain solar reflectivity. Lack or
  periodic cleaning may significantly reduce energy
  savings for reflective roofs.
• Reflective roofs can generate additional savings
  in warm climates by reducing the overall size
  (and initial cost) of cooling equipment and
  reducing peak load requirements.
• For some buildings, the solar heat gain lost in
  winter by a reflective roof may be offset in part
  by internal sources of heat such as occupants and
  equipment.
• Energy-savings will vary with local energy costs.
  Calculations in this presentation are based on
  2001 full year national averages for commercial
  electricity (0.075 per kwh) and natural gas
  (0.75 per Therm).

17
SolarSmart
If I want a reflective roof, which should I
choose?
Step 1 Step 2
Choose an Energy Star Rated Roof Decide between
a membrane or a coating
18
SolarSmart
If I select a reflective roof, which should I
choose?
Step One Choose an EnergyStar Rated Roof
EnergyStar roofs have been certified by the
manufacturer to

• Provide 65 initial solar reflectivity
• Provide 50 solar reflectivity after 3 years

19
SolarSmart
If I want a reflective roof, which should I
choose?
Step Two Decide between. a high-quality
membrane or coating
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SolarSmart
Membrane Advantages / Disadvantages
After 3 years, membrane will loose 30 to 50 of
reflectivity due to dirt collection and
biological growth.

• Reflectivity integrated into membrane
• 10 to 20 year service life, depending on warranty
  
• Tend to discolor due to dirt accumulation and
  microbial growth
• Require frequent cleaning to maintain
  reflectivity

Actual roof test panels at Oak Ridge National
Laboratories
However, proper cleaning procedures can restore
up to 90 of reflectivity.
21
SolarSmart
Coating Advantages / Disadvantages

• Tend to self-clean with sun, rain and proper
  drainage
• Extend service life of underlying roof membrane
• Require re-coating approximately every 5 to 10
  years, depending on warranty