In an earlier blog, we covered the effects of high relative humidity (RH%) in the home environment and the adverse effect it can have on occupant health. But what about low RH%?

When the RH% is low it can often feel a lot colder than it is, that is because the moisture is evaporating from any exposed skin faster. We have all experienced one of those days where, even though the sun may be shining bright, there is just a wicked chill in the air even though there is no real obvious wind.

While we have no control over the weather outside, we do have control over the conditions inside.

In the Home

Low RH% in the home can result in not only damage to your health but to your walls as well. When the RH% is low the dry air can draw moisture out of items in your home. Anything made out of wood is susceptible, as wood items naturally contain moisture and having that moisture removed can cause items to split and crack, causing damage which can be expensive to replace or repair.

Having a low RH% in your home can also lead to the paint on the walls and ceilings drying out and beginning to crack and peel. This can be unsightly and expensive and if you live in an older home you run the risk of exposure to older lead-based paints.

Because low RH% makes us feel colder when we experience it in our homes, we often turn on the heater to help warm ourselves and our surroundings. Depending on the heater, this can dry the air out even more. Using a wood fire heater would dry out the air whereas a free-standing combustion gas heater produces water vapor as a by-product. Running heaters to keep warm also comes with the additional strain on the wallet.

Low RH% can also increase the amount of static electricity in the air, I don’t know about you but personally, I am not a fan of getting zapped every time I touch a door handle or worse when my partner tries to give me a kiss. And don’t forget the effect static electricity has on hair, all of the frizzy-haired ladies know what I mean when you just can’t tame the mane.

Impact on Health

Spending time in a low RH% environment can have some pretty common symptoms, experiencing itchy eyes, a scratchy throat and dry skin are prevalent. However, extended periods in low RH% can result in the mucous membrane in your sinus drying out. This membrane is your bodies main defense against colds, cases of flu and viruses when this membrane is reduced your chances of becoming sick increase significantly.

Research shows that the flu virus lives longer and spreads faster in a low humidity environment, important information when we are experiencing one of the worst flu seasons recorded.

People who have eczema or psoriasis will tell you how much they suffer during the colder months. The cold dry air absorbs moisture from exposed skin and those who already have difficulties in retaining that moisture suffer terribly from sore, dry, itchy patches of skin. But it’s not just the skin that dries out.

Dry eyes are another indicator the RH% is too low, we all know the irritation of dry sandy eyes, when your eyes become dry you blink more to keep them moist, the increase in blinking can make your eyes feel tired and strained.

Increasing Humidity

If the RH% in your home is low the cure is to bring it back up, this can be done by using humidifiers. These are available for purchase online or in store, there are even varieties in which you can place essential oils to make your home smell nice. However, there are also more cost-effective methods that you can do every day with little effort.

Steam it up

Typically, the following are things I would advise against, however in a low RH% environment the ‘habits’ that would usually result in moisture and mould problems are exactly what is needed.

  • Boil a pot of water on the stove, no lid, no extractor fan.
  • Take a nice long hot shower, or bath, with the door open and exhaust fan off.
  • Have a pot of tea, let the tea steep in the hot water for a while.
  • Let your clothes air dry, rather than using the dryer, hang them indoors to dry.
  • Get a house plant, plants release moisture from their leaves and stems – as long as you take good care of them.

Creating steam is the fasted way to increase the RH% in your home, but be careful not to overdo it, having the RH% too high can cause all sorts of problems too, including surface mould growth.

If you would like more information or if you have any questions or queries, please feel free to contact us on (08) 9355 1060 or drop us an e-mail –