How To Look At A House

McGarry and Madsen's home inspection blog for buyers of  

site-built, mobile/manufactured and modular homes

What is a cool roof?

Tuesday, August 14, 2018

“Cool roof” is a designation for roofing material that significantly reduces the amount of heat transferred through the roof and into the home in two ways:

  1.  Solar reflectance - Bouncing the sun’s heat back off the roof.

  2.  Thermal emittance - The ability of the roofing material to radiate absorbed heat back into the atmosphere.

    Both reflectance and emittance are rated on a scale ranging from zero to one, with one being the highest rating. The EPA’s Energy Star program, which rates cool roof materials as a basis for a rebate plan, requires that cool roof products have a reflectance of 0.65 at installation and not less than 0.50 after three years of weather exposure. Standard asphalt shingle roofs, by comparison, have a reflectivity of between 0.06 and 0.26, which results in transfer of large amounts of solar heat into the home.

   Cool roof materials can be manufactured panels or flexible sheets, such as metal coated with a high-white finish or white TPO (Thermoplastic PolyOlefin -rubber-like, single-ply roofing, shown in photo at top of the page), an asphalt shingle roof with reflective granules, or a coating applied over an existing roof. The graphic below is from a catalog for Gulf Coast Supply and Manufacturing’s metal roofing color selections, with the reflectance and emittance ratings below two of their  whites. You will also see a “Solar Reflectance Index,” which is a summary rating of performance.

   To learn more about cool roofs, click on the link below to download a report by the Cool Roof Rating Council (CRRC). 


• • • • • • • • • • • • • • • • • • • • • • • • • • • •  

  To learn more about roofs and attics, see these other blog posts:

Why is my roof sheathing sagging between the trusses?

Why is granule loss a problem for an asphalt shingle roof? 

What are the mistakes to avoid when doing attic improvements?

What causes roof shingles to curl up at corners?  

What causes shingles to buckle along a line on the roof?

What causes leaks at a fake roof dormer? 

What causes a sagging roof ridge line?

What causes bubble-like blisters in a built-up and gravel roof?  

Why does it cost so much more to replace a steep roof than a low slope roof? 

What is "ponding" on a flat roof?

Is an attic required to have a light by the building code? 

How can I inspect my roof for hurricane damage?

Why is premature curl of roof shingles a problem?

How can I tell if a roof has more than one layer of shingles? 

What are the common problems with attic insulation? 

What is the life expectancy of an asbestos cement shingle roof? 

What's the average lifespan of a roof?

Why is it a mistake to replace a roof and not replace its flashings? 

Why is there no attic access hatch in the house?

What is the building code requirement for an attic access hatch, scuttle, or door? 

     Visit our ROOF AND ATTIC page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

Graphic - Cool Roof Rating Council

Water Heaters

Water Heater Age

"What Are The

Signs Of..."

Septic Tank Systems

Structure and Rooms

Plumbing Pipes

Termites, Wood Rot

& Pests



When It First

Became Code

"Should I Buy A..."

Park Model Homes


Shingle Roofs




Wind Mitigation

Roof and Attic

"Does A Home


Pool and Spa

"What Is The Difference Between..."




Concrete and

Concrete Block

Metal Roofs


Modular Homes

Rain Gutters

Mold, Lead & Other Contaminants


Older and

Historic Houses

Crawl Spaces

Mobile-Manufactured Homes

Building Permits

Life Expectancy

Clay Soil





Exterior Walls

& Structures


Common Problems

HUD-Code for

Mobile Homes

Garages and Carports

Flat (Low Slope) Roofs

Electrical Panels

Sprinkler Systems

Electrical Receptacle Outlets

4-Point Inspections

Hurricane Resistance

Frequently Asked Questions (FAQ)

Home Inspection

Heating and Air Conditioning

Building Codes

Fireplaces and Chimneys

Inspector Licensing

& Standards

Energy Efficiency

Washers and Dryers



Doors and Windows



Electrical Wiring

Click Below  

for Links

to Collections

of Blog Posts

by Subject

Plumbing Drains

and Traps


Smoke & CO Alarms

Aging in Place

Top 5 results given instantly.

Click on magnifying glass

for all search results.






Air Conditioner & Furnace Age/Size


Electrical Switches





Water Intrusion

Electrical - Old

and Obsolete


Foundation Certifications

Tiny Houses

About McGarry and Madsen



Buying a home in North/Central Florida? Check our price for a  team inspection by two FL-licensed contractors and inspectors. Over 8,500 inspections completed in 20+ years. In a hurry? We will get it done for you.

Moisture Problems

Crawl Spaces