• How Humidity Affects HVAC Performance and Home Comfort

    When you picture home heating and cooling, you probably think of raising and lowering the temperature to keep your home comfortable. However, there’s more to home comfort than just the temperature – humidity plays an equally important role. Learn how humidity affects HVAC performance and home comfort in all seasons.

    High Humidity in the Summer

    In Florida, high humidity is commonplace. The air often feels muggy and heavy outside, and you can’t wait to rush into the nearest air-conditioned building. It’s important to understand that air conditioners don’t just remove heat from your home – they also dehumidify. This occurs naturally as a side effect of the cooling process.

    The evaporator coil housed in the interior portion of your AC unit grows very cold as chilled refrigerant flows through it. As air blows over this coil, it’s stripped of heat. Moisture in the air also condenses on the evaporator coil, the same way water forms on the outside of an ice-cold glass of lemonade. This moisture drips off the coil and into a condensate pan where it drains away.

    While your AC unit removes some moisture from the air, it might not be enough in Florida’s humid climate. Here are some signs that you should take measures to combat high indoor humidity:

    • Cool but clammy feeling – Sweating is your body’s natural ability to cool itself. If the air is already so saturated with moisture that your sweat doesn’t evaporate quickly, you’re left with a clammy feeling, even if you set the thermostat to a comfortable temperature. You may be forced to turn the temperature down further, increasing your cooling bills as a result.
    • Musty odor – High humidity promotes mold growth, especially in moisture-prone areas such as the basement and bathroom. If these areas have a lingering musty smell, you should get the humidity under control before any damage occurs.
    • Foggy windows and plumbing fixtures – Air conditioners can remove humidity because moisture condenses on cold surfaces. At room temperature, glass and metal feel cool to the touch, so water condenses here first. Check your windows and plumbing fixtures for a layer of moisture. That’s a clue your humidity level is too high.
    • The reading on a hygrometer is 50 percent or higher – The goal is to keep indoor relative humidity below 50 percent. When it rises above this level, people tend to feel uncomfortable. An inexpensive, handheld hygrometer lets you measure the moisture content in the air so you can find out for sure if it’s too high.

    How to Control Humidity in the Summer

    In some buildings, running the air conditioner is enough to lower the relative humidity to 50% or lower. If you discover this isn’t the case in your home, which is common in Florida’s subtropical climate, here are the steps you can take to control humidity:

    • Install a whole-house dehumidifier – The most effective option is to integrate a dehumidifier into your HVAC system. This allows you to control the moisture content in every room with an easy-to-program humidistat. A whole-house dehumidifier works in tandem with your air conditioner, but it can also run independently to remove excess humidity on mild days. This maximizes home comfort while keeping your utility bills as low as possible.
    • Place a portable dehumidifier in problem areas – If certain rooms are more prone to high humidity than others, a portable dehumidifier may solve your problem. Just remember, this small unit can only control the moisture in one area at a time. You’ll also need to empty the condensate pan manually when it gets full.
    • Generate less humidity – To reduce the amount of water introduced into your home, cook with covered pots, take shorter showers, and run the kitchen and bathroom exhaust fans while cooking and showering. Also, make sure the dryer vents directly to the exterior, not the attic or basement, and reduce the number of houseplants you have.
    • Seal leaky areas of your home – If hot, humid air sneaks in through gaps and cracks in your home’s outer envelope, your air conditioner and dehumidifier are forced to work harder. Seal leaky windows, doors and attic floor penetrations to keep conditioned, dehumidified air inside where it belongs.

    Low Humidity in the Winter

    Humidity levels drop naturally in the winter because cold air can’t hold as much moisture as hot air. Still, in Florida’s subtropical climate, the air stays warmer and more humid throughout the winter than other parts of the country. This may have you wondering whether your Tampa home needs a humidifier. Look for these signs of low humidity to help you decide:

    • Dry skin, lips and nasal passages – If you find yourself reaching for lotion or lip balm in the winter when you never need these products in the summer, you’re experiencing the drying effects of low humidity. Irritated nasal passages and waking up with a bloody nose are other signs that the humidity level is low.
    • Increased instances of static shock – Dry air carries an electrical charge more readily than humid air. This makes you prone to static shock when you touch a doorknob, reach for a light switch or pet the family cat.
    • A feeling that it’s colder than it really is – Low humidity causes moisture to evaporate from your skin at a faster rate than usual, creating a cooling effect. If you can’t believe how cold you feel despite the thermostat reading, adding a little humidity to the air could be just what you need.
    • Higher heating bills – Because low humidity makes you feel cold, and the natural response is to turn up the thermostat, you could be left with higher utility costs. Remember last winter when temperatures in Tampa, FL were much colder than usual? The relative humidity was lower than normal as well. Prevent another shock this winter by taking steps to increase indoor humidity.
    • A reading of 30 percent or lower on a hygrometer – The ideal indoor humidity level in the winter is between 30 and 40 percent. Any lower than this and you’re bound to experience signs of dry indoor air.

    Regulating Humidity in the Winter

    If lack of moisture has caused comfort issues in the past, take control this winter with these tips to increase indoor humidity:

    • Install a whole-house humidifier – As with the dehumidifier you use in the summer, a whole-house humidifier integrates with your HVAC system. This delivers moist air to every room when the furnace runs according to the setting you program into the humidistat. This way, you can carefully control the relative humidity level to reach the ideal 35 percent.
    • Place a portable humidifier in your bedroom – Low humidity affects people the most while they’re sleeping. To keep your nose and throat moist, run a humidifier at night. You can do this whether you have a whole-house humidifier or not. Just remember to fill the reservoir and turn on the unit before you go to bed.
    • Introduce moisture to the air – Natural evaporation increases humidity. Hanging your clothes to dry inside and leaving wet towels out are two low-tech options for doing this. However, the strength and control of natural evaporation is limited, and you must continually rewet the items you leave out, which could lead to mold growth.

    Whether you’re struggling with high humidity in the summer or low humidity in the winter, the experts at Air Rescue can help. We install whole-house humidifiers and dehumidifiers to help our customers’ homes stay comfortable in every season.

    To learn more about humidifiers and dehumidifiers, or to schedule installation services, please contact Air Rescue today at (813) 375-9982. We have over 70 years of experience serving residents of Tampa, Largo and the entire Bay Area.