How to Adjust a Humidifier on a Furnace

Setting the Humidistat

Read the humidifier instruction manual before making any adjustments. While most whole home humidifiers work similarly, there might be some differences in how to adjust them. Always check the manual before you make changes to avoid any mistakes or problems. If the instruction manual provides different instructions, then follow the manual instead. Those directions are designed for that specific product.

Locate the humidistat for your humidifier. The humidistat is the control panel for the humidifier. It’s usually a small box mounted on the wall directly above or below the humidifier. Some models also have a humidistat on the main humidifier body. If you have trouble finding the humidistat, look for a wire or cable running out of the humidifier. This should lead to the humidistat. A digital humidistat will have a screen displaying the current humidity settings and a few adjustment buttons. An analog type will have a dial.

Turn the dial to your desired humidity setting if it’s an analog type. An analog humidistat has an adjustment dial to set the humidity level. The lower numbers represent a lower humidity setting, and the higher numbers represent a higher setting. Turn the dial until you reach your desired humidity level. The dial might have numbers or percentages to represent the humidity setting. Either way, as the numbers go up, so does the humidity level.

Press the up or down arrow buttons if you have a digital humidistat. A digital humidistat should have buttons instead of a dial. The same rules apply though – raising the numbers raises the humidity, and vice versa. Press the up or down buttons until you reach your desired humidity level.

Wait 24-48 hours to see if your home is comfortable. It takes some time for the new humidity level to take effect, so wait about a day to see if the adjustment worked. If you still need more or less humidity, then adjust the humidistat again. If you see condensation on the windows or walls, then the humidity setting is too high. If the air feels dry and your lips and mouth are drying out, then it's too low.

Finding the Right Setting

Start with your humidistat set in the middle. If you don’t know where to start with your humidifier setting, then you can figure out the best setting by beginning in the middle. Set the humidifier right in the middle between its highest and lowest settings. On most humidifiers, this is about 4 or 5, but the scale depends on the model. The exact middle setting depends on your humidistat. Some might go from 1 to 10, and others might use a different scale like 1 to 7. If your humidistat uses a percentage setting, try setting it to 40% to start. This is a good middle setting that many people find comfortable.

Wait 24-48 hours to see what the humidity level feels like. Let the new humidity setting take effect for about a day. After that, you’ll be able to tell how the home’s humidity feels. After this, you can adjust it either way based on your comfort level.

Turn the humidistat down if you see condensation on your windows. This is a sign that the home’s moisture is too high. Dial the humidistat down 1 or 2 positions and check back in 24 hours. If the condensation stops and the home feels comfortable, then this is the right setting. Don’t leave your humidifier on a level that causes condensation. This can cause mold growth. You’ll probably have to readjust the setting as the seasons and temperature change. This usually leads to condensation.

Increase the humidity if you’re getting shocks or the air feels dry. If your home is too dry, the first thing you’ll probably notice is that you get shocks when you touch things. This is because dry air causes static electricity to build. Your throat or eyes might also feel dry, which is another sign that the humidity is too low. Set the humidifier up 1 or 2 positions and see if this fixes the problem. If 24 hours pass and you feel more comfortable, then this is a good setting. Some other signs that your home is too dry are bloody noses, your eyes or lips drying out, feeling thirsty, and dry skin.

Select the automatic setting if your humidifier has the option. Some newer digital humidifiers have an automatic setting, which means it adjusts itself based on the outside humidity and temperature. This can save you the trouble of having to adjust it regularly. Check the humidistat for an “automatic” button, or look in the instruction manual, and set the humidistat to adjust itself if you want to. Even if you have your humidistat set to automatically adjust, you should still be able to set it manually if you want to make any changes. Continue monitoring your home’s humidity levels even if you have the humidifier set to adjust automatically. The automatic setting isn’t always ideal.