What’s the Ideal Humidity in Florida Homes?

Florida has high humidity compared to most other states — we feel it most days in the hot, sticky weather. But did you know that it ranks second in the country for relative humidity at 74.5 percent?

That’s far too high for a home to be comfortable. Anything above 60 percent can feel stifling when combined with high temperatures. So, is there too much moisture in the air inside your home — and if so, what’s the ideal humidity level in Florida?

If family members are constantly complaining “I can’t breathe in here!” what can you do about it? And how does your HVAC system affect the humidity levels?

Here’s everything you need to know about relative humidity and humidity levels in Florida as well as how your home air conditioning system or a dehumidifier can help…

What’s the ideal humidity level for a house in Florida?
What is relative humidity?
Why is high humidity bad for a house in Florida?
What are the main causes of high indoor humidity in Florida homes?
How can you monitor humidity in your home?
How can you lower humidity in your Florida home?
Do you need a humidifier in Florida?

What’s the ideal humidity for a house in Florida?

Generally speaking, homes in Southwest Florida should strive for an indoor relative humidity of between 45 and 55 percent. This will maintain comfort, avoid related health issues and prevent problems with mildew and mold.

If you’re asked to describe Florida weather, you’ll probably mention the word “humid”. Residents here are well used to days when it seems like there’s no air and you’re constantly sweating.

Humidity levels result from evaporation and tend to be highest in regions near large bodies of water — like Florida, which is surrounded by sea on three sides. This greatly affects the air in your home. with comfort levels impacted by high humidity as well as high temperatures.

The humidity levels across Florida average out at around 75 percent but some areas experience 90 percent humidity at some times of the year. This can be very uncomfortable and it’s certainly not ideal for the inside air quality of your home. Your home should be a sanctuary of coolness where you can escape the elements.

Aim for an indoor humidity level of between 45 and 55 percent. This is a practical, energy-efficient and comfortable target that will help keep your home cool and dry even during the hottest and wettest time of year.

The question is how do you reduce humidity from 75-90 percent to 45-55 percent effectively? We’ll get to that soon…

If you’re facing an urgent humidity problem and need an HVAC professional to assess the need for a dehumidifier or to tune up or repair your air conditioning, call the team at One Way Air at 239-233-4356.

What is relative humidity?

Humidity is a measure of how much moisture is in the air. We usually refer to relative humidity (RH) rather than absolute humidity. This is a measure of the amount of moisture the air contains expressed as a percentage of the amount of moisture it could contain at that temperature.

If the relative humidity is 74.5 percent (as is the average in Florida), the air holds 74.5 percent of the moisture it could hold at the current temperature.

Relative humidity affects the heat index (see below), which helps us analyze comfort levels by measuring what the temperature feels like to the human body.

Florida’s average relative humidity is second only to Alaska. But, in Alaska, the temperatures are generally much lower than in Florida. The higher the temperature, the more moisture the air is able to hold. So, comfort levels in a Florida home with 74.5 percent humidity will differ markedly from an Alaskan home at 75 percent RH.

Remember, as air cools, its relative humidity may increase even if the total amount of moisture remains constant. Dew or condensation may then form.

High temperatures combined with high relative humidity (as we often experience in SWFL) create oppressive conditions that few people find “comfortable”. Normally, the human body sweats to cool down and the evaporation of sweat off the skin into the air helps with the cooling process. If the humidity is high, sweating is less effective at cooling the body, making us feel uncomfortable and sticky. The moisture simply sits on your skin and is unable to evaporate.

On the other hand, low temperatures with high relative humidity (like in Alaska) can be comfortable if you have enough warm clothing and heating (the body may feel more chilled on a cold day with high humidity). Similarly, relatively high temperatures coupled with low relative humidity (like in desert heat) may also be tolerable.

70 percent relative humidity may be comfortable if the temperature is 75F or below but not if the temperature is above 80F.
40-60 percent relative humidity is comfortable at a variety of temperatures from the high-60s to the mid-80s.

Why is high humidity bad for a house in Florida?

Excessive humidity in a Florida home can lead to:

Discomfort
Health risks
Damage to property

You’ve already seen how excessive humidity combined with high temperatures can impact comfort levels in the home.

The National Weather Service’s Heat Index addresses how humidity and temperature can also combine to pose health risks. The following graphic explains more:

When the temperature rises above 80F, anything above 40 percent relative humidity requires some caution and 88F with 75 percent humidity is considered a dangerous heat index level, with potential health risks.

With prolonged exposure or physical activity, the orange or red zones can lead to health problems, such as heat stroke, heat cramps or heat exhaustion.

Another potential problem with high humidity is damage to property inside the home. Mold and mildew are microscopic fungi that thrive in moist conditions. Certain items are particularly susceptible to mold and mildew in humid conditions.

If you notice moldy or musty smells and/or see white or gray patches forming on items, that’s mildew. Typical locations include shower curtains and bathroom tiles. Mold is black or dark green and can penetrate deeper into building materials.

In humid homes, these unsightly problems can extend beyond the bathroom and start to result in damage to

Soft furnishings, books and carpets
Ceilings and floors (in extreme cases, structural damage)
Paintwork and wallpaper
Wooden products
Electronic equipment (rusting and corrosion to the exterior or interior)
Walls and brickwork (e.g., warped drywalls)

Mold is a destroyer and can also trigger allergic reactions and lead to other health problems, such as asthma: another reason why you should aim to maintain 45-55 percent relative humidity in your home.

Another potential problem is insect infestations as many bugs, such as dust mites and cockroaches, are particularly attracted to warm, moist environments.

Excessive humidity in your home can even increase energy usage when cooling your home, leading to higher energy bills. This is because when humidity levels are high, your HVAC system must work harder to remove excess moisture from the air.

Can low humidity be bad for a house in Florida?

Low humidity (below 30 percent RH) is rarely a problem in Florida homes but it can lead to problems when we travel on planes.

Dry air results and this can cause skin dryness or cracking, respiratory discomfort, nasal issues, allergy triggering and irritation in the eyes.

What are the main causes of high indoor humidity in Florida homes?

The most obvious cause of high humidity in Florida homes is the climate, which we’ve already established.

Beyond that, homeowners may contribute to the humid indoor air quality by failing to ventilate their homes sufficiently and neglecting to service their air conditioning systems effectively.

Poor ventilation can result from blocked supply and return air vents (make sure that furniture or rugs are not obstructing the vents) or the lack of extractor fans in confined spaces particularly susceptible to high humidity, like kitchens, bathrooms, and laundry rooms.

However, many homeowners don’t realize how much their air conditioning system also affects humidity levels. Besides cooling the air, an AC system removes excess moisture, naturally cooling and dehumidifying homes.

So, if your central air conditioner is poorly maintained or the wrong size, this may make the air excessively humid or, in some cases, too dry.

For instance, an air conditioner that is too large may short cycle (run and shut off frequently, which doesn’t give the system the time it needs to dehumidify the space properly.

Similarly, an air conditioner that receives little maintenance can develop problems with a dirty evaporator coil, which, when dirty, becomes less effective at removing moisture from the air.

A properly installed and maintained AC system should result in an ideal humidity level within the 40-60 range, which will feel relatively comfortable for most residents in SWFL.

Ultimately, however, poor ventilation, coupled with a poorly maintained or sized air conditioner and activities such as air-drying clothes indoors can result in uncomfortably high humidity in Florida homes.

How can you measure and monitor humidity in your home?

The most common way to measure humidity in a home is by experience. Most people know if it’s uncomfortably humid by sweat levels. You may also notice condensation gathering on cold surfaces, such as windows or countertops (note that some condensation in air-conditioned homes is normal).

However, humidity and heat are closely intertwined when it comes to comfort levels, so pinpointing what’s causing the discomfort (heat or humidity) can be difficult without using specialist equipment.

A hygrometer is a humidity sensor, i.e., a small instrument that measures the amount of water vapor in the air relative to the maximum it can hold (relative humidity). These can usually be picked up for as little as $10-$12 from your local hardware store or online.

Indoor air quality monitors are a smart idea too. Understanding the quality of the air inside your Florida home in detail can help maintain comfort and prevent future problems. An air quality monitor can alert you to potential problems with your air, including humidity levels.

An inspection from a licensed HVAC professional is another great way to identify red flags with humidity. Call us at 239-233-4356 to schedule an air quality inspection from one of our certified HVAC professionals or an AC tune-up to prevent issues from arising.

How can you lower humidity in your Florida home?

So, you have less than ideal humidity in your Florida home? What can you do about it?

If serious humidity problems are left to worsen, they may require serious professional assistance to remedy. However, some sensible steps can be taken before you let it reach that stage.

Don’t underestimate the role that your AC plays in maintaining air quality in your home. With 96 percent of Florida homes relying on AC for cooling, air conditioning systems are one of the main causes of humidity problems in Florida homes.

An AC system works by extracting warm, humid air from the home, cooling it and removing moisture before forcing it back to the living space. So, you can see how important it is to humidity levels.

A well-maintained central AC system keeps a constant temperature throughout the home, removes moisture from the air and limits condensation. Ideally, schedule a tune-up with an HVAC professional twice a year and regularly check to make sure that all AC vents are clean and unobstructed.

A standard element of any tune-up or AC service agreement is cleaning the evaporator coil, which helps to remove heat and moisture from the air. If dirt and debris accumulate, it becomes less efficient at removing moisture and cooling. Furthermore, ensuring that all parts of your AC system are functioning as they should during a tune-up will help maintain the right temperature, airflow and humidity level.

An HVAC professional can also check that the AC system in your home is sized correctly to cool and dehumidify your home optimally and, if not, recommend the next steps.

Other ways to lower humidity in Florida homes

Regular checks of your roof and brickwork (particularly after storms) can also help ensure that water’s not entering your home through structural issues. If rainwater is seeping in through the roof or an exterior wall or there is a plumbing leak, this needs to be fixed as a priority.

Proper ventilation of your home is also important, especially in moist, poorly ventilated spaces like bathrooms, kitchens and laundry rooms. Extractor fans and box fans may help at times. Opening windows usually helps reduce humidity but the humidity outside in Florida may be higher than in your home, so opening windows and doors may be no help!

Avoid air-drying clothes indoors if you sense a humidity problem, as this may contribute to it — use a dryer, as this will channel moisture away from the home if correctly installed.

The Department of Energy also has some good recommendations for properly controlling moisture in your home. These include:

Improve the drainage around your property: poor runoff from the gutters or standing water can enter your home through the air and add to humidity levels.
Improve the insulation in your home: this can lower humidity levels as well as energy bills. Insulation effectively creates a barrier between the indoor air and the outdoor air, so that excessive moisture in the air outside finds it more difficult to enter your home.

If you can’t immediately lower humidity, look after your health by staying well-hydrated (drinking enough water), wearing lightweight, breathable clothing and avoiding exercise during the hottest parts of the day.

Do you need a humidifier in Florida?

Humidifiers and dehumidifiers achieve opposite goals. A humidifier adds moisture to dry air and a dehumidifier sucks moisture out of the air.

Air conditioning systems are natural dehumidifiers but if your Southwest Florida home is too humid to be comfortable, you may benefit from having a separate dehumidifier installed. These are specialist appliances designed specifically to suck moisture from the air and are especially useful in living spaces that are difficult to keep ventilated using other means.

As most homes in Florida have central air conditioning systems, a dehumidifier may already be integrated with your HVAC system. If not, this can be added or a separate, dedicated unit can be installed by an HVAC professional.

If you decide to invest in a dehumidifier, the next question is whether to get a whole-home device that integrates with your HVAC system or a portable dehumidifier. This will largely depend on what you have installed already and whether your humidity problem is confined to a corner of your house or is more widespread. It’s best to seek advice from a licensed HVAC professional about this.

You may also decide to install a humidistat, which is a device that measures humidity and automatically turns a dehumidifier on or off according to whether the room meets the desired humidity setting.

Maintain ideal humidity and temperature in your Florida home…

There’s not much we can do about the humidity outside the home in Florida but indoors is another matter!

Regular tune-ups and AC troubleshooting are an essential part of maintaining a healthy, low-humidity indoor air quality in your Florida home. For stubborn humidity problems, installing a dehumidifier may help.

At One Way Air, we help Florida residents maintain the ideal humidity level to promote health and comfort and protect their property and possessions.

if you’re in Fort Myers or the surrounding areas of SWFL, schedule a tune-up or discuss how to reduce your humidity levels. Call us today at 239-233-4356 to solve your air quality issues.