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What is the Proper Level of Home Humidity?

Humidity in your home

Let’s face it, managing humidity levels in your home can be a challenge. In winter, it seems like one day your throat is dry and scratchy, and the next, your windows are icing over. In summer, you feel clammy one day, and the next, you’re scratching dry skin and reaching for the hand lotion. So, what is the proper level of home humidity for Minnesotans? And what can we do to keep our homes comfortable for our families and pets?

Here's everything you need to know about ideal indoor humidity.

Signs of Too Much or Too Little Humidity

Your five senses will clue you in to any humidity issues. A musty or moldy smell is a big indicator that an area of your home has too much moisture. Keith Hill, technical support manager at Minnesota Air, says that mold can grow at a 60% humidity level. That means you may be able to see mold growth in places where you’re getting too much moisture.

When it comes to the other end of the spectrum — not enough moisture in your home — you’ll be able to see it, hear it, and feel it. You may see cracks in wood flooring or furnishings. You may hear your floors and doors creak a little more — especially in the drier winter months. And you may feel some of the more uncomfortable signs of low humidity — static electric shocks, dry skin, and chapped lips.

Unfortunately, some signs of a humidity imbalance can be more than just uncomfortable. They can lead to health issues and damage to your home. With low humidity, chapped skin and lips can mean more colds and viruses or skin infections. In your home, it can mean warping doors, splitting furniture, or peeling paint. With high humidity and mold comes any number of concerns: allergy, asthma, and other respiratory problems, wood rot, and pests that eat away at it, and even structural damage to your home over the long term.

Causes of High or Low Humidity

For some families, moisture generated by normal day-to-day activities can lead to high humidity levels. Showers, cooking, laundry, and dishwashers naturally add moisture to the air. High humidity levels within your home can cause moisture to condense on windows, water to “sweat” on walls, and rust and mold to form. In winter, the outdoor air is so dry that it affects your indoor relative humidity when it enters your home. In summer, too low a temperature setting on your AC can also reduce humidity.

How to Check Your Home's Humidity Level

Besides using your senses to determine if you have a humidity problem, there are instruments and tools to help you get a more accurate sense of what your humidity levels actually are.

Keith says one of the better instruments is a hygrometer — or humidity gauge. (Many new digital thermostats have them built in.) “That makes it very convenient — we already look to the thermostat for temperature, so why not have both on the same device?” he says. “Many can be set up to display it on the main screen along with temperature. Some require you to push a button to see it. Some that are internet-linked will show you temperature and humidity on your smartphone or tablet.”

Keith notes that most of the thermostats that have built-in humidity sensors will also control a humidity appliance such as a humidifier or a dehumidifier. He recommends checking with a pro to see what options there are for your system because a whole-house humidifier/dehumidifier is one of the best solutions for remedying moisture issues. For other solutions, check out our blog on home humidity solutions.

If you need a separate device to read humidity, look for a quality digital device, Keith says. “Low priced humidity gauges are not accurate,” he says. “Spend a few extra dollars to get a precise instrument.”

Adjusting Your Home’s Humidity

If you have a whole-house humidifier/dehumidifier, it will be controlled by a humidistat, which works similarly to a thermostat. A ventilator (HRV or ERV) can also be used to control wintertime humidity and it can be controlled by your humidistat. A good rule of thumb for controlling humidity in the winter: If frost or condensation forms on your windows, the humidity is too high and you should turn down the humidistat. If your hardwood floors start to separate, the humidity is too dry and you should turn up your humidistat. Setting the humidistat may not be a one-time fix. You may need to occasionally adjust it, depending on outdoor temperature  and your comfort level.  

Sometimes, turning down your humidistat isn’t quite enough. You may have to resort to additional measures to reduce the moisture in the air, such as running your bathroom exhaust fan during baths and showers, and for an additional 30 minutes or longer after bathing or showering to remove moisture from the room. Also, operate the kitchen exhaust fan when you’re cooking.

Adding humidity to a dry house is fairly straightforward. A whole house humidifier is best but an inexpensive stand-alone, cool mist humidifiers will get the job done. Clean humidifiers regularly, especially the stand alone models, and don't let water stand in the bottom of them —humidifiers can put harmful microorganisms or bacteria into the air if not properly maintained.

The Proper Level of Home Humidity

The University of Minnesota has developed guidelines for the maximum recommended humidity levels for houses. Based on a 70ºF interior room temperature, and single-pane windows, engineering studies established the following guidelines. Above these values your windows may “sweat” or frost. Add 10 to 15%% to the humidity values for double pane or triple pane windows.

Outside Temperature

20º to 40º

10º to 20ºF

0º to 10ºF

-10º to 0ºF

-20º to –10ºF

-20ºF or below

Inside Humidity

Not over 40%

Not over 35%

Not over 30%

Not over 25%

Not over 20%

Not over 15%

Managing your home’s humidity levels will leave you feeling healthier and more comfortable while protecting your home at the same time. If you need help controlling your home’s humidity or want to learn more about a whole-home humidifier/dehumidifier system, use our convenient dealer locator to find a reliable HVAC pro near you.

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