Does a dehumidifier work with windows open? HVAC experts agree on the answer and the best way to run them in winter

While in winter you probably won't be tempted to throw your windows open at all times – sometimes it feel necessary. Whether to help you sleep better, air out condensation or simply for some crisp, fresh air, it's unlikely that you keep your windows sealed all season long.

But, if you have and use a dehumidifier, will it still work with windows open?

To avoid any dehumidifier mistakes, we spoke to HVAC experts who all agree you shouldn't leave your windows open when running this appliance. Instead, here's what to do, and how to get the most out of yours.

Does a dehumidifier work with windows open?

Having quizzed multiple HVAC experts, it turns out that even the best dehumidifier won't work effectively with windows open during operation.

John Gabrielli, HVAC expert and owner of Air Temp Solutions, explains, 'You can use a dehumidifier with a window open, but it's not the most effective way to operate the device. Dehumidifiers are built to pull moisture out of the air in a space that's closed.

'When you open a window, you let in air from outside, which usually has different humidity levels. This forces your dehumidifier to work overtime, trying to manage moisture from both inside and outside.' That's not only less efficient, but, like any heating system mistakes, could also increase your energy bills.

All prices correct at time of publication.

How to effectively use a dehumidifier in winter

Given that opening windows in winter reduces condensation, you should aim to open your windows in winter when necessary – to release cooking odors or to help you to sleep better for example, but, importantly, turn off your dehumidifier when doing so.

As Max Veggeberg, CEO and founder of Tetra says, 'A dehumidifier is designed to work in an enclosed space. Keeping a window open would continue to bring in humid air from outside into the enclosed space. If you are looking to use a dehumidifier most effectively, close all windows and doors into the space you are looking to dehumidify.'

But, that being said, Simon Bernath, HVAC expert and founder of FurnacePrices.ca points out that, if opening your windows only briefly for a bit of fresh air, this shouldn't cause too much of a problem. 'What homeowners can do is get a humidity sensor, and monitor the relative humidity differences, so you have a better idea,' he says.

We recommend the bestselling AcuRite Indoor Digital Thermometer & Hygrometer available at Walmart for this, which provides reliable and accurate readings at an affordable price point.

You may also want to consider using your best fan instead of opening a window, suggests Steve Pacholski, brand president of Varsity Zone HVAC. 'This will keep the air moving without affecting the humidity inside,' he says.

FAQs

Will a dehumidifier clear condensation from windows?

Yes, a dehumidifier will clear condensation from windows – in fact, it's one of the best ways to stop condensation on windows overnight, particularly if you know the best place to put a dehumidifier. Put them directly next to your windows in any rooms where humidity is a problem for the best results.

When should you not use a dehumidifier?

As well as when windows are open, you shouldn't use a dehumidifier if temperatures are under 60° Fahrenheit, as this may cause removed moisture to build-up and freeze on the coils. Therefore, while a dehumidifier doesn't make a room cooler, they may be damaged irreparably by cooler conditions.

If you've got one at home, learn about the ways to reuse dehumidifier water around the home next for an eco-friendly alternative to pouring the water away.