As the season changes and many of us start cranking up the heat in our homes and studios, it’s important to remember to protect guitars from damage due to low humidity. While this environmental issue can affect all types of stringed instruments, acoustic guitars are most susceptible to damage to tone, playability, and finish.
Expert opinions vary but most set the optimum humidity for a guitar’s well-being at around 45%. When the heat goes on, temperatures go up while relative humidity goes down. Prolonged exposure to low humidity (below about 40%) can cause cracking in both the wood and lacquer. The top can drop, lowering action to the degree that the strings will buzz, sometimes to the degree that the guitar becomes unplayable. Lacquer checks may develop along the purflings, bindings, and at glue seams. The fingerboard can shrink, leaving the fret ends protruding beyond the edge of the binding.
If you’re not able to maintain relative humidity of about 45% in your room, the best way to protect your guitar is to keep it in its case with a humidifying source such as the Guard Father. This simple, low-tech device consists of a plastic container filled with clay. Submerse it in water for 5 minutes, wipe off the excess moisture, and then store it in your case. “Recharge” the humidifier with water about twice a month.