Toys For Tots

There is still one more day to bring in toys! Tomorrow, Friday, December 16th, we will be taking the toys to one of the Toys for Tots warehouses just after lunch. If you have anything you want to drop off in the morning, please feel free to come by and say hello!

Lower Energy Bills with Cool Roofs

Managers specifying a cool roof only a few years ago found a limited number of product options. Now, based on the growing demand in part by institutional and commercial facilities, managers can choose from among hundreds of cool products.

By reducing the amount of heat transferred to a building’s interior, cool roofs provide a number of additional benefits. These include lower energy bills and longer performance lives for roof systems, as well as cooling equipment.

The environment also benefits from cool roofs. By lowering facilities’ energy use, cool roofs cut down on air pollution — including carbon emissions, which contribute to global warming.

Managers also need to pay attention to the return on investment — an especially important consideration in tough economic times. While some cool-roofing options cost more than standard, non-cool options, a cool roof generally will pay for itself in a relatively short time through savings in energy costs. But managers should note that exact savings depend on a number of factors that include climate zone, product type, building insulation and the type of HVAC equipment used to cool the building.

Understanding the concept behind a cool roof does not fully describe the amount of actual energy savings managers can expect. Savings obviously can vary widely, but the difference in temperature between a cool roof and a regular roof can be large.

Climate, roof performance, insulation and other aspects of the building can cause variations in the exact amount of savings, but cool roofs can yield up to 50 percent savings on cooling loads.

Average savings in the range of 10-30 percent of the cooling energy required is a reasonable expectation for a typical application of cool roofing under normal conditions. This range might equate to a drop in the total electric bill of 3-10 percent. These ranges generally apply to low-rise buildings in regions with significant cooling loads.

Cool Roofs Reject Heat, Lower Cooling Loads

The availability of viable and energy-efficient cool roofing products has expanded greatly in recent years. Building owners and managers, specifiers, and architects increasingly use these products because of their capacity for energy savings.

Managers in institutional and commercial facilities also can achieve several other benefits, such as: lower interior temperatures, greater occupant comfort, and smaller cooling loads on HVAC systems. A growing number of building codes also mandate the use of cool roofs, and more voluntary programs include them as a key element of sustainable design.

By understanding some of the science behind cool roofs and the questions to ask in specifying these systems, managers can more effectively match product options to the organizations’ needs.

How Is It Cool?
Specifying a cool roof for an institutional or commercial facility can be a smart decision, but not everyone is clear on what exactly cool entails. Cool roofs have been around for quite some time and are increasingly popular options in many areas of the United States. Still, managers often do not understand the performance details of cool roofs.

A cool roof is highly reflective and can easily emit the small amounts of heat it absorbs, allowing the surface of the roof to remain cooler, and transferring less heat into the building.

Two radiative properties define a cool roof. Solar reflectance describes the fraction of solar energy the roof reflects. Thermal emittance describes the relative ability of the roof’s surface to radiate absorbed heat. Both of these properties are measured from 0 to 1, and the higher the number, the cooler the roof.

Here is where part of managers’ confusion comes in. Many elements of a roof’s structure, such as insulation, can affect a building’s interior temperature and its performance. These elements are obviously important, but “cool roof” refers specifically to the roof’s radiative surface properties.

It stands to reason that light-colored surfaces have high reflectance, and many early rebate programs for cool roofs used this characteristic as the only requirement. Uncoated shiny metal surfaces reflect the sun’s energy efficiently, but they have very low emittance and, as a result, become very hot during the day. A roof that demonstrates both high solar reflectance and high thermal emittance is essential for managers seeking to improve a facility’s energy performance.