Many people are aware of the problems caused by high humidity during the warmer summer months when it’s easy to feel suffocated by the conditions. But, high humidity can be a problem all year round, and this is a particular issue indoors. Our HVAC systems actually work as a dehumidifier during normal operations, and they can remove some of the humidity outdoors. In this article, we will take a closer look at humidity, how it can affect our homes, and what you can do about it in your home.

Relative Humidity Concerns

When you think about the indoor humidity levels in your home, it’s the relative humidity that you need to consider carefully. This is easy to measure with an inexpensive digital hygrometer that you can find online or in your nearest hardware store. For optimal health, it’s advised that the humidity should be in the 40-60% range. This will help you to avoid many of the irritating aspects of high humidity when the indoor air becomes far too dry for comfort.

This is easy to maintain in summer when the air conditioner is running, but when the weather turns colder, the conditions change. During the winter months, it’s advisable to keep your indoor humidity at the lower end of the aforementioned 40-60% range. In fact, in some homes, it’s often a good idea to drop below 40% relative humidity to protect your home and maintain indoor comfort levels.

The Need for Lower Indoor Humidity

It’s important to understand that colder winter air is dry, and although your home may be well sealed, the change to winter conditions will cause the humidity in your home to drop naturally. If your home is not sealed well, the cold air can infiltrate the indoor spaces and cause the humidity to drop significantly. This often manifests in a physical way for the occupants with symptoms, such as dry eyes, sore throats, dried out skin, and sore nasal passages.

There are other problems to consider, wood furnishings can be damaged by the indoor humidity levels, and static electricity can build up in your home. The only way to fix this problem is to boost the humidity in the home with a humidifier, but this creates a new set of problems due to condensation.

Condensation in Your Home

If the indoor temperature is too high when compared to the external conditions, you can see droplets of moisture form on the internal surfaces of your windows. Sometimes these droplets may even freeze on your glass surfaces, creating a thin sheet of ice! If the condensation problem is severe, the condensation may even form on your ceilings and walls. In some parts of the home, it may be less obvious that this is occurring, and there could be condensation inside your walls or in the attic.

Excessive volumes of moisture quickly buildup when the doors and windows are kept shut to keep out low outdoor temperatures. This moisture buildup can rot any wooden fittings or furniture in your home and promote the growth of toxic mold and mildew. The growth of mold will release thousands of mold spores into your indoor air, and this will have a dramatic effect on your air quality. Anyone in the home with a pre-existing breathing condition may find it harder to breathe freely, and the mold spores can trigger allergic reactions in some people.

If your home is well insulated and sealed against external temperature conditions, condensation will be less of a problem. But, it’s always a good idea to get your insulation levels checked if you’re not sure how your home is performing. Any improvement that you can make to your envelope and home insulation will be beneficial. Better insulation will make your home more energy efficient and help you to control the humidity and condensation indoors. That being said, it’s also important to monitor your relative humidity levels throughout the colder winter months.

Going Lower Than 40º Relative Humidity

We mentioned earlier that it might be a good idea to stick to the bottom end of the 40-60% relative humidity level and even lower in some cases. But, what does that mean? How low can you go once the winter temperatures drop below 40ºF outdoors? According to recent guidelines, the following temperatures should guide your choices when considering indoor relative humidity levels.

  1. If the outdoor temperature is 20ºF to 40ºF have a maximum indoor humidity of 40%.
  2. If the outdoor temperature is 10ºF to 20ºF have a maximum indoor humidity of 35%.
  3. If the outdoor temperature is 0ºF to 10ºF have a maximum indoor humidity of 30%.
  4. If the outdoor temperature is -10ºF to 0ºF have a maximum indoor humidity of 25%.
  5. If the outdoor temperature is -20ºF to -10ºF have a maximum indoor humidity of 20%.
  6. If the outdoor temperature drops below -20ºF have a maximum indoor humidity of 15%.

The Importance of Consistent Monitoring

As you can see from the figures above, it’s essential to keep an eye on the thermometer and the hygrometer if you want to combat indoor humidity. It’s important to avoid overusing humidifiers to correct the relative indoor humidity, and the underlying problems should be addressed first. Improving insulation and seals around doors and windows is a passive way to save energy and fight against humidity problems. On the other hand, a humidifier can be expensive to run over the winter, and it could really drive up your energy bills.

Better Solutions to Humidity Problems

If you have problems related to the relative indoor humidity in your home, it’s time to consult an HVAC professional for expert help and advice. An energy audit can highlight areas where you need to improve insulation levels, and there are systems that can help to control humidity and condensation. A whole home humidifier paired with a smart thermostat will give you simple control over the relative humidity in your home. This will remove a lot of the guesswork and allow you to have unparalleled control over the environment in your home during the entire year with a simple app on your smartphone, mobile device, or computer.