How to (Accurately) Test Your Home’s Humidity


There are many reasons why someone might want to test their home’s air to see what its humidity is. Maybe you’ve got an endless bloody nose. Maybe a dry cough. Maybe dry and cracking skin. (All signs of low humidity.)

Or, maybe you’ve got some mold, lots of condensation, or your home just smells damp.

Perhaps you’re just curious.

Whatever your reason, here’s a list of ways that you can test your home’s humidity with ease!

The Three Best Ways to Check Your Home’s Humidity:

  1. Ice Water Test
  2. Check Windows or the Pipes Under Your Sink.
  3. Get a Hydrometer (Humidity Sensor).

Now, before we dive into things, I must say that the first two options don’t hold a candle to the third. (That means they’re nowhere near as good.) The fact that you can get a perfectly fine hydrometer for about five dollars makes it a pretty easy choice as well!

If you’d like to pick up a hydrometer right now, you can get it on Amazon here. (By the way, it’s Prime eligible too, so you can get fast shipping!)

And, if you do end up buying a humidity sensor, then you are looking for a readout between 35 and 50, as per the EPA’s guidelines. Anything higher than that is problematic as are things lower than that. And, before you freak out, trust me, it’s not too hard to keep your home in the safe zone most of the time! (Read on and I will outline the ways you can either increase or decrease humidity.)

Now, with that out of the way, I’m going to explain how you can do each method. They’re all super simple, so anyone and everyone will be able to do them!

The Ice Test

This is probably the second easiest way to test your home’s humidity, after buying a hydrometer. (I know a hydrometer sounds techy and scary, but they’re easy to use, trust me!) To conduct the ice test, get a cut–preferably one made of glass. If you don’t have a glass cup, then a ceramic bowl or a ceramic mug can work. The latter two options will require a longer time to sit, however.

To keep things simple, I’m just going to outline the steps for the ice in a glass method.

Steps:

  1. Get a glass.
  2. Put in a couple pieces of ice, pour in some water, stir a bit.
  3. Let it sit for three to five minutes.
  4. Check for condensation on the outside of the glass.

Quick note, be sure to run this test when you aren’t cooking if it’s in your kitchen. Additionally, don’t do it in your bathroom while someone is showering. Both could result in “false positives”. If you do want to test these rooms, allow a half-hour or so to pass before running the test.

With that out of the way, here’s what the results of your test will mean:

-If you see a lot of water on the outside of the glass, then you likely have higher humidity than you ought to. (You might need a dehumidifier. (Dehumidifiers pull moisture out of the air.)
-If there isn’t any moisture on the outside of the glass, then your home’s humidity is rather low and you might need a humidifier. (Humidifiers add moisture to the air. They’re also AMAZING for when you have a cold and are very congested.)
-If there is just a tiny bit of moisture forming after three to five minutes, then you probably don’t have much of a problem.

Now, this test isn’t the most accurate one out there, but it should give you a rough idea of what you’re looking at. If you want accuracy, you’ll need to buy a humidity sensor and see its readouts and go from there.

Something else of note is that your home’s humidity fluctuates through the course of the day, week, and year. While dealing with daily and weekly changes isn’t very feasible, dealing with seasonal ones is. So, pro tip, humidity is higher during the spring, summer, and fall, as temperatures outside are higher. During the winter, humidity levels will be lower.

The Window or Pipe Test

This test is potentially the hardest, since you’ll usually have to wait until wintertime to check your windows or pipes. Additionally, you need to have metal pipes under your sink for this to work, and most sinks nowadays just have PVC where you’ll need to be checking. (Mine does, so I won’t have a picture for you all!)

Now, if you are in the middle of summer and it is hot out and you still have condensation on your windows or pipes, then that is a sure indication that you have a severe humidity problem, but that would be an extreme case.

For most people, all you need to do is just walk over to your window (during a cold day) and check for condensation. If there is some, then you’ve probably got a humidity problem and possibly a leak too.

Additionally, you might want to check under your sink. When you check under your sink, you’ll need to spot the P trap. If you’re older, then you might want to enlist the help of a younger person for this.

The P trap is a spot that looks sort of like the picture I drew on the right. The point of them is to hold some water at the low point. That’s good news for us! Why? Well, that water will be cold enough to attract condensation if there is too much humidity in your home.

So, as you can see in my beautiful picture (that’s sarcasm there), the water will be sitting rather low, so check the lower part of the P trap for condensation. (And check for any leaks while you’re down there too!)

Unlike with the ice test, this test won’t really show you if there isn’t enough humidity in your home, but it’s a free test you can do without having to really do much of anything, which is why it’s on our list.

Testing For Humidity With a Hydrometer

Finally, we have the best way you can test your home’s humidity levels. Again, I bought this particular sensor for less than five dollars, so they’re uber cheap. They won’t break the bank!

This particular humidity sensor from Amazon (click here to check it out), is simple to use and, again, very cheap.

There are fancier ones out there that can do more, and even some that have smiley faces and frowny faces to tell you if the humidity level in your home is healthy. Despite that, I know a lot of people don’t want to spend money that they don’t have to, so I recommend this one.

But that isn’t to say that you can’t check out the ones that have the smiles! They’re neat! You can see one of them on Amazon here. This particular one (that I just linked to) is one of the best ones out there, as I see it, and it’s still very cheap. Plus it smiles, so that’s a selling point in itself! Hahaha

Anyways, back to the subject at hand.

When using a hydrometer, follow these steps:

  1. Place the hydrometer in the room you want to check the humidity level of.
  2. Leave the sensor in the room and walk away.
  3. Come back after at least five minutes–fifteen or so is preferred.
  4. Check out the readout.
  5. Repeat the above steps once every few days or months. (Try to check it at least once a season, more times can’t hurt though.)

Step five is optional and you don’t have to wait to do it if you think you need a humidifier or dehumidifier right now. As I said earlier, you will want to have a number between 35 and 50, which is the EPA’s recommendation.

If the readout is below that, then you will need a humidifier. If it is above it, then a dehumidifier will be your best course of action. But, as I alluded to before, you might need a dehumidifier some seasons and a humidifier others. It’s totally normal!

What is the Difference Between a Humidifier and a Dehumidifier?

Humidifiers increase humidity levels in the air by shooting water up into it (either via hot steam or a cool mist). Dehumidifiers, on the other hand, decrease humidity levels.

Here’s a little way to remember: DEhumidifiers DEcrease humidity.

(I don’t have anything clever for humidifiers.)

If your home’s air is dry, then you’ll want a humidifier. So, if your ice water test ended up with a dry cup or if your hydrometer says anything below 35, then your air is dry. Humidifiers can be super affordable, plus the cool mist ones are incredibly cool and they’re also fun to play with. (They shoot out “steam”, but it’s cold. It’s really wacky!)

If your home’s air is wet, then a dehumidifier is your best bet. If you’ve got lots of condensation on your pipes, or on your glass, then you’ve got too much humidity and you need to decrease it. Additionally, if your humidity sensor is reading anything over 50, then you’ll need a dehumidifier too. Those are really cool, but they’re not as fun to play with as I see it.

If you’d like to learn more about which option you need, you can check out this post I wrote: How Do I Know if I Need a Dehumidifier or a Humidifier? | What’s the Right Humidity for My Home?

Or, if you’d like, you can pick up a dehumidifier from Amazon here. Or, if you need a humidifier, here is one for you. Both options are units that I personally own and use. I highly recommend both.

What Can Happen if I Don’t Address My Humidity Problem?

There are two very different humidity problems that you can have in your home. On the one hand, dry air will have a host of issues for you. On the other, high humidity (wet air) will have others. Both are very different, so I think a table will best explain things.

Humidity Too Low
(Dry Air)
(Humidity Below 35%)
Humidity Too High
(Wet Air)
(Humidity Above 50%)
Can cause, or worsen congestion.
Can worsen allergies.
Can cause wood to splinter and crack.
Can cause skin to dry and crack.
Can cause eye and throat irritation.
Can cause dehydration.
Can cause or worsen chapped lips.
Can cause mold and mildew to overtake your home.
Can ruin your paint and the wood in your home.
Can worsen allergies.
Can encourage dust mites to take over.
Can encourage bed bugs to take over.
Can make your home more appealing to spiders and other bugs.

Now, I’m not guaranteeing that any of these things can happen–especially if the humidity issue is just season-related and is only extra-bad for a couple of days. Some people will be more susceptible than others, myself included.

I know of plenty of people who purchase dehumidifiers and humidifiers for use in just a few days of the year and they think it is worth it. Personally, I think it is worth it as well–hence why I have them! They’re super helpful and very neat too. I highly recommend them.

That’s all I’ve got for today, before I decide to go and share even more information! But, if you’d like to continue reading stuff I’ve written, I’ve linked some articles I think might interest all of you below.

How Do I Know if I Need a Dehumidifier or a Humidifier? | What’s the Right Humidity for My Home?

Does My Basement Need a Dehumidifier?

How to Clean My Home’s Air

Jonathon Silva

Jonathan Silva is our longtime Air Purifier Essentials author. He has been writing on air purification technologies for his entire professional career.

Recent Posts