In this era of continued rising energy costs and concerns about the environment, choosing the right roofing system is often a complex problem that contractors, architects, and building owners face. The old rule of thumb when choosing between black and white roofing was “white is always right”, but now, empirical data is causing many authoritative roofing experts to avoid jumping to conclusions. So which is better: black or white roofing? Let’s compare the pros and cons of both.
Which is Better: Black or White Roofing?
Initially, the white roofing bandwagon gained so much steam that some cities suggested that slapping white paint on black roofing would solve a full range of problems, from saving energy to eliminating the heat islands that are melting the ice caps. But white roofing is now getting a long second look. Tom Hutchinson, a nationally recognized consultant on roofing issues, even said, “Attempting to effect change with a single component mandate is a faulty approach.” So how does one choose between black and white roofing?
Despite the complexity of the challenge, there are key questions that can help building professionals clarify their construction needs and select a suitable roofing system. These questions don’t deal directly with roof color, but they do provide important guidance about whether to use a black or white roofing membrane in specific situations.
1. “Does my property’s climate demand more heating days or cooling days?”
In other words, will you spend more money heating a building with a reflective roof than what you’ll save on air conditioning costs? This question is especially pertinent in cool Northern climates, where building owners spend up to five times more on heating their buildings than on cooling them. In these situations, common sense tells us that a reflective roof may actually increase energy costs, energy consumption, and carbon emissions.
Hard science supports the same conclusion: a landmark study from the University of Kansas in 2010 concluded that when white roofing is used in Northern climates, “Global space heating increased more than air conditioning decreased, suggesting that end-use energy costs must be considered in evaluating the benefits.”
2. “What type of insulation will be used, what is the R-value, and how many layers will be installed?”
State-of-the-art research is revealing that insulation levels are either equal to or more important than roof color in affecting energy efficiency. Additionally, appropriate levels of insulation can mitigate the condensation problems that have been associated with white roofing in cooler climates.
Mike DuCharme, Director of Product Marketing at Carlisle SynTec Systems, said, “It’s important to look at all of the factors involved when you are choosing a roof. Assess all of your costs – insulation, roof membrane, projected energy use – and then make your decision. For instance, EPDM roofing membranes are available in both black and reflective white. But it’s important for the designer to work with the roof membrane manufacturer to determine the best choice for your specific climate, and the best combination of roof color and insulation R-value.”
3. “How long will the roof last?”
This very simple question is often overlooked in discussions about sustainability. Common sense tells us that a roofing system that lasts a very long time makes less of a dent on the environment and the budget vs. a roof that has to be replaced frequently.
Recent studies have shown that black EPDM will last in the field for more than 30 years, and in laboratory tests for 50 years. “The bottom line is that the durability of EPDM makes it a smart long-term option one can’t afford not to consider,” said Jennifer Ford-Smith, Director of Marketing and Single Ply Product Management at Johns Manville.
Choosing Between Black and White Roofing
Building owners have more choices than ever, and with an EPDM roof available for every climate, white roofing is not automatically the best choice. While the most economical approach is to always care for the roof you have, when it’s time to choose between black and white roofing, be sure to consider:
- Your energy use in both winter and summer
- Your insulation materials and levels
- Your roof membrane
- Your local climate
Get Advice on Black and White Roofing From NIR
If you need help deciding whether black or white roofing is better for your building, the Roof Care Specialist®s at NIR can help. We’re available 24/7 via our mobile app, but you can also contact us for additional assistance. We’re here to answer all your questions and help you make an informed decision!