Based on our industry experience, the answer is, yes. Attic fans do have a role to play. They will help circulate air in your attic and ventilate the space to keep it closer to the outside temperature. Attics can reach extremely high temperatures during the hot summer months and collect excess moisture during the winter months. Attic fans will help with these problems.
Can they really deliver significant energy savings? The answer to this will ultimately depend on where you live, the type of fan you install and whether your attic is well sealed.
For those who live in cold or temperate climates, attic fans may not be worth the price of installation (if you are only concerned about energy savings). Passive roof vents may be sufficient, and if your goal is to gain energy savings, you may want to consider air sealing or adding insulation.
There is also the debate about electric vs solar fans. Electric fans do what they're supposed to do, but you need to take into account the average cost of powering them. Many electrically powered attic fans also only have a 1-3 year materials warranty, so you will likely need to replace them at some point. Solar powered fans will work all year round, cost you nothing and have a much longer warranty.
So, do attic fans really work? Yes! But ultimately it depends on what your goals are. If you are looking for significant energy savings, you will need to utilise the fan with other practices such as adding insulation and air sealing the attic. If you just want to add ventilation to help comfort and protect your roof, just installing an attic fan will certainly help.