Some studies show that radiant barriers can reduce cooling costs 5% to 10% when used in a warm, sunny climate. The reduced heat gain may even allow for a smaller air conditioning system. In cool climates, however, it's usually more cost-effective to install more thermal insulation than to add a radiant barrier.
How much does radiant barrier save?
The tests to date have shown that in attics with R-19 insulation, radiant barriers can reduce summer ceiling heat gains by about 16 to 42 percent compared to an attic with the same insulation level and no radiant barrier.
Will radiant barrier keep heat in?
Radiant Barrier Insulation Benefits
Works to keep warm air in during the winter and solar radiant heat out during the summer. Prevents up to 97% of solar radiation. Improves energy efficiency and lowers utility costs, especially if HVAC and duct systems are located in the attic.