Piano Humidifier

Creating a Healthy Environment for Your Piano

If you have an acoustic piano you'll want to take the best possible care of it, and the most important factor is the room environment. Once you have your acoustic piano placed properly in your room, away from a heater and direct sunlight, the most important factor is the humidity.

What is the proper humidity for your piano?

Modern premium pianos are very robust by design and can handle a fairly wide range of humidity levels. Ideally, your piano will be in a room with a controlled climate that avoids frequent rapid fluctuations in both temperature and humidity.

According to Steinway, 45 to 50 percent relative humidity is the optimum range for their pianos.

Another premium manufacturer, Fazioli, simply advises, “The humidity level should never be lower than 30% or higher than 70%.”

I asked Thomas Broukal, Technical and Manufacturing Director for Bösendorfer, for advice. He was a wealth of information and helped and reassured me. Here’s what he said:

• Anything between 30 and 70% is acceptable and will not harm your piano. This is the exact range that Fazioli also recommends.
• Bösendorfer’s official recommendation is 40–60%. However, Thomas Broukal told me, “Our recommendations are perhaps a bit too high actually.” He said the Bösendorfer factory in Wiener Neustadt, Austria has a relative humidity of 38% during winter.
• If your humidifier has a hygrostat that allows you to set a target humidity level, setting it to 40% in winter is perfectly fine.
• Rapid and significant changes in humidity are undesirable. If the room changes from 30% to 70% within a very short time, your piano’s tuning might be affected, although it should escape any actual damage since these levels are within the safe zone. The wood in a piano also doesn’t immediately dry out, but should the humidity drop below 30%, you should definitely turn on a humidifier right away. If the air is too dry for too long, that can cause cracks in the soundboard that can significantly damage your precious instrument.
• The danger zones are < 30% and > 70%. At these levels a humidifier or dehumidifier, respectively, will bring the room climate back into the safe zone.

Types of humidifiers

Cool mist

This type of room humidifier filters the water and sprays a mist into the air. I’ve had a Boneco 7131 for quite a number of years. It’s a very basic, small humidifier, nothing fancy. There’s no display and no way to tell the current humidity without a separate hygrometer. It still works just fine, though it quickly became clear that it would be insufficient for my Bösendorfer. One weakness is that increasing the amount of spray will only saturate your floor or carpet since the air isn’t able to absorb the humidity fast enough. There’s therefore a limit to using this type of humidifier when it gets very dry.

Warm mist

I then tried a much higher-end model also from Boneco, the U650. This model is both a cool mist and warm mist humidifier. It seemed fine for a while but turned out to be pretty problematic. For starters, it sprayed white dust all over! This was a result of hard water and a quickly used filter cartridge. A couple times a day I had to wipe off my piano when I used this humidifier.

Also, the warm mist function will drive up your electric bill. It requires a constant 120 W of electricity (compared to 3 to 8 W for the model I ended up getting).

Finally, once the filter was used the humidifier would stop working every few minutes or even seconds. I went to buy new filters, only to discover that Boneco (which until recently was branded Air-O-Swiss in the USA) no longer distributes their products in Austria for some reason, even though the company is headquartered in neighboring Switzerland.

Dampp-Chaser “Piano Life Saver”

A more sophisticated solution is a dedicated humidifier built directly inside your piano. There’s an American company, called Dampp-Chaser, that has manufactured a piano humidifier and dehumidifier system for decades. Branded the “Piano Life Saver,” it keeps your piano’s humidity at around 42%. These are a significant investment at between $500 and $800 (US), and they need to be installed by your piano technician.

I asked Bösendorfer if they recommended having this system installed for my Imperial in Vienna. They replied that while it’s definitely a quality product and they sometimes recommend it to owners, it’s really best for special circumstances. Ideally, the room humidity will match the piano’s humidity, rather than having the piano’s microclimate differ from the immediately surrounding air. Most pianos in most settings will be happiest with a room humidifier like the one recommended below. If you live in an extremely variable climate and a room humidifier does not solve your piano’s humidity issues, having the Dampp-Chaser piano humidifier system installed will surely prove to be a worthwhile investment.

Recommended humidifier

Bösendorfer highly recommended humidifiers from a German company called Venta. It turns out that these are Steinway’s recommendation as well, and Venta even has a webpage dedicated to the benefits of using their products to care for musical instruments.

Venta airwashers operate on a simple principle: A fan gently sucks in the room air, slowly turning a series of discs in water. The water captures dust particles, cleaning the air, and part of the discs are exposed to air, which then evaporates. This method has several significant advantages:

• Never over-humidifies: Venta airwashers keep the humidity to 45 to 55%. Beyond that, the air simply won’t absorb any more water, so you can leave it turned on and not worry about saturating the air.
• Cleans the air! When I got my Venta LW45, my bathroom was being renovated. There was dust all over, even though I practically barricaded the living room. The Venta captured dust bunnies and visitors commented on how clean the air was!
• Very low power consumption: Venta models use only about 3 to 8 W of power.

You might want to get the next larger model for your room size. Rather than running a smaller model at its maximum, the larger model will have no problem keeping your room at the right humidity for your piano (and lungs). I got the LW45 model, which means I can travel for a few days and not have to worry about it running out of water every day.

I’m really happy with mine, and so is my piano.

Share your experiences with humidifiers for your piano below!