Do I need a permit to install a central humidifier? In some cases 100% Get Free Quotes Today! Question: Do I need a permit to install a central humidifier? Top Answer (100% of 4 votes): In some cases. Answer: In some cases Explanation: I guess in some municipalities you would. Arizona's Best Heating & AC, Inc. Answer: In some cases Explanation: It would depend upon the mechanical codes in your area. APSCO Professional Service Company Get Free Quotes Today! Find Local Pros Free Whole House Humidifier Installation Cost Estimates Related Questions How Much Does It Cost to Replace Humidifier on Furnace? Can I install a whole house humidifier without a forced air system?Top answer: In some cases Who can install a whole house humidifier? Can I install a whole house humidifier if I have a heat pump?Top answer: In most cases What is humidity?