Some professional carpet cleaners exclaim: “Heaters are for cheaters when it comes to drying carpets in the cold of winter.
These carpet cleaners explain this “theory” below:
“When you add heat to your home in winter, it can create a subtropical climate (like the Mediterranean, Noosa, Hong Kong. You know how your windows and glass sliding doors fog up when it’s super toasty inside and frigid outside? That’s because there’s moisture in the air, which in turn allows you (or the kids) to draw pictures in the condensation on the windows and glass doors.
Unfortunately, it’s not as fun for your carpet that’s trying to dry out because the water in the carpet is competing with the water in the air (humidity). The water in the carpet wants to be free! To give it the best chance of emancipation via evaporation, you need to give it an empty runway by ensuring there are fewer water molecules in the air so it’s best to turn the heater down, or even off. A bit chilly while you follow this golden carpet drying tip? Sub-blanket naps, fashion shows in all your wintry numbers (that means all your jumpers, socks and scarves at the same time), and duvet forts are delightfully cozy!”
Their hypothesis is however only half correct, the above statements reflect both a poor hypothesis and an well thought out observation. Sadly it is only half correct. True, cold air contains less moisture which according to this professionals opinion should allow your carpets to dry faster if you turn your heater off. However, if we look at the physical nature of cold air v. hot air we’ll find this hypothesis incomplete, at best.
Using Psychrometry: Debunking the cold air carpet drying hypothesis
Psychrometry is the science of study of various properties of air, methods of controlling its temperature and moisture content or humidity and its effect on various materials and human beings.
Air contains some water molecules, bouncing around as individual gas molecules. When the water molecule density is high, they bump into any little drop-like clumps more often than molecules fly off the clumps. The clumps grow into drops and fall out, sticking to surfaces. That’s what dew is.
The hypothesis postulates that “The colder the molecules, the less often they fly out of the drops, so cold air has less water in it and thereby will allow for quicker evaporation”. Where it goes wrong is cold air is dryer because it can’t hold the water. Cold air, like in a home with the heaters turned off holds a lower density of water molecules than warm air.
Simply put: the colder the air, the less moisture it can contain. That is the absolute humidity, i.e. the volume of water per volume of air.
When you warm the air in your house or office, it still won’t have many water molecules in it, because it comes from the cold outdoor air. Now warmed, that once cold dry air, can hold more water. If your HVAC unit has a humidifier it is time to turn it off. Moving this warm “dry air” along the surface wet or damp carpets will allow for maximum exposure of the warmed air in your carpeted space. This process will pull water at a faster rate from your carpeting into the warm air which we now know will hold more water. Removing the excess water from the air with a dehumidifier will capture the excess moisture allowing for quick, thorough extraction protecting your furnishings from damages from the excess moisture in the air. While simultaneously decreasing the risk of water damage to carpet’s padding or the flooring under them both.
Warning: While not always feasible, it is highly recommended to remove all furnishings from a room that is having it’s carpeting cleaned to avoid water damage from either direct contact or excess humidity created by the addition of water to the air in the cleaning and drying process. Furnishings should not be returned until the carpets are thoroughly dry and the humidity levels have returned to what is normal for your space.