How to measure humidity in a room

When it comes to knowing how to measure humidity indoors the most accurate method is to use a machine called a hygrometer. This is a specialist piece of equipment that measures temperature and humidity. But you don’t have to invest in a hygrometer to get a good insight into how to measure humidity in home; you can give the following methods a try instead:

Measure for optimal indoor humidity – wet and dry bulb thermometer method

You’ll need two thermometers for this method. Follow these steps:

Leave one thermometer as it is – the dry thermometer.
Wrap a wet piece of cloth (room temperature water) around the bulb of the other thermometer – the wet thermometer.
Place your thermometers in the room where you want to test the humidity level. It’s important you do all of the steps in the same room, to make sure that the mercury always starts recording the temperature in the same conditions.
Leave for around five minutes, and then note the temperatures of each thermometer.
Subtract the wet thermometer temperature from the dry thermometer temperature to find what is called the depression value.
You can then use an online calculator or chart (don’t worry, they’re easy to find!) and enter the reading to get your humidity level.

Measure for optimal humidity for house – ice cube method

Who’d have thought something as simple as a few ice cubes could help you measure and get a better idea of whether you have the recommended humidity at home? It’s a very basic test, but should give you an insight into the general levels. Here’s what to do:

Pop two to three cubes of ice in a glass with water.
Leave for four to five minutes.
Check the results – if the glass is dripping with condensation that’s an indicator that humidity levels are high. However, if there’s no condensation at all, that indicates the air is too dry.
It’s worth bearing in mind that this isn’t a very effective test in a kitchen, as cooking vapours can cause unreliable results, so try and do this test in another room, if possible.

What’s a Good Humidity Level & How to Measure | Philips Home