Yes. A trained contractor will have experience and advanced testing tools to help find hidden leaks and seal them up quickly. Even if you are a do-it-yourselfer, in some cases you may need to call in a contractor for certain parts of the job (e.g., if you have old electrical wiring, roof damage, attic ventilation issues, or if you need to address recessed can lights in the attic floor). A professional can also perform a combustion safety test after air sealing to make sure your furnace, boiler, or water heater are venting properly after sealing. Visit the Seal and Insulate with ENERGY STAR website for more information.