Summer cooling can significantly add to the running costs of your home and contribute to harmful greenhouse gas emissions. You can reduce both costs and emissions through the installation of radiant barrier sheathing. NASA has utilized radiant barriers on its astronaut suits and equipment since the Apollo mission as they are very effective at keeping out radiant heat. Radiant barriers are extremely effective at reducing summer heat gain in attic spaces.
Summer heating can have a huge impact on your attic temperatures. This heat is transferred through to your living space and makes your home much warmer. Radiant barrier sheathing can significantly reduce attic temperatures and can save you up to 17% on your summer cooling costs.
How radiant barriers work
Heat is transferred through conduction, convection and radiation. Heat is conducted through materials and is transferred through air by convection. In the hot summer months, solar energy heats the shingles and roof sheathing by conduction which causes the underside of the roof to radiate heat down into the attic space. A radiant barrier prevents the sun’s heat from being radiated into the attic space which reduces the amount of heat that moves down into your living spaces below.
Types of radiant barriers
There are a number of different types of radiant barriers including thin radiant barrier foils, foil-faced bubble wrap or roof sheathing panels. It’s important to remember that the reflectivity of the surface is not an indication of its efficiency and that radiant barriers need to have an emissivity of 0.1 or less in order to effectively reflect heat. Radiant barriers which record the highest efficacy are those which consist of a roof sheathing panel with heat-reflective film laminated to one side, but these are a more expensive option.
In order for radiant barriers to work, the attic needs to be properly ventilated. If radiant barriers are installed on top of other materials, they will simply conduct heat through these building materials. Install them with the reflective surface facing into the attic adjacent to ventilated air space. Keep the reflective surfaces clear of dust to ensure their efficacy.
Benefits of radiant barriers
Your attic temperatures can be reduced by up to 30°F if installed with adequate ventilation. This means that your summer cooling costs are reduced and that the lifespan of your shingles may be increased.
Lower attic temperatures also increase the efficiency of your attic ductwork and prolong the life of your HVAC system.
Radiant barriers can contribute to LEED certifications and may qualify for government energy efficient rebates.
Radiant barriers can only be installed on new roofs or when your roof is being replaced. Speak to your design professional about whether radiant barriers are right for your climate zone.