What Causes High Humidity in Your House

I have talked about the benefits of having a power humidifier in your home to combat a low humidity environment, but too much of a good thing is typically a bad thing.   High humidity encourages mold and mildew growth – yuck!   What causes high humidity in a house is an interesting question with multiple answers.  Continue reading to gain a better understanding of the various causes of high humidity in your house.

Humidity is simply the measurement of the amount of water vapor in the air.  Sources of high humidity in a house revolve around, you guessed it, life; breathing, bathing, cooking, laundry, and your HVAC system. High humidity often presents as condensation build-up on the interior of your windows or with a musty smell in your basement.   Let’s look at some of the causes of humidity in your house.

Sources of Low Humidity

  • Breathing:  Yes, breathing does release water vapor into the air, but unless you are consistently breathing very rapidly, it’s probably not the source of high humidity.
  • Plants:  Plants do release humidity into the air, but as long as you do not have a greenhouse in the living room, they are probably not the cause of high humidity in your house.

Sources of Medium Humidity

  • Bathing:  We have all taken an extremely long steam shower and have drawn big happy faces on the bathroom mirrors…okay, maybe not, but your kids have.   Having a bathroom vent and fan that vents to the outside are imperative to stopping the effects of bathroom humidity.   Multiple showers per day without proper ventilation will add a considerable amount of humidity inside your home.
  • Laundry Room:  Depending on the amount of laundry you do, the dryer, if not properly vented can be the cause of a little or a lot of humidity.  The dryer should vent directly outside at all times to decrease the possibility of the humidity it creates being released into your house.

Sources of High Humidity

  • Ventilation:  Ventilation or lack of ventilation will cause high humidity in a house, especially during colder months.  While having a tightly sealed home is perfect for energy efficiency, occasional fresh air circulation will help relieve localized high humidity.  On the occasion that this does not help, there is a possibility that you may need a Continuous Ventilation solution, Energy Recovery Ventilator (ERV) or Heat Recovery Ventilator (HRV) to aid in fresh air circulation.    
  • HVAC issues:  The air conditioner is really quite a clever piece of equipment; utilizing a continual cycle of conversion to create cool, dehumidified air.  In a basic description, the air conditioner uses refrigerants to cool the warm air, evaporator coils to absorb, and condenser coils to push the warm air outside.  However, this whole process creates humidity and if the refrigerant is low or one of the coils isn’t functioning correctly, you will experience high humidity levels in your house.
  • Foundation:  While it is tempting to crank on the portable dehumidifier when you smell a musty smell in the basement, it is best to find the moisture problem first, repair and eliminate it.

There really isn’t a simple answer as to what causes high humidity in your house and there really isn’t a reason to live in an uncomfortable home environment due to humidity.  If you are experiencing high humidity inside your home and have tried all the solutions you can think of, give us a call.  Our qualified technicians are here to answer questions and find solutions.