A healthy and comfortable home should have a humidity level of 30-50 percent, regardless of the season. Too much indoor humidity decreases your comfort in the summer and causes structural damage to your house. Dehumidification can reduce health issues for occupants and prevent damage to your home caused by mold growth.
Sometimes it's hard to know if you have an indoor humidity problem until the weather gets excessively warm. The human body evaporates water to cool itself and when the indoor humidity is too high that moisture won't dry as quickly. As a result, you will feel sticky and uncomfortable inside your home.
Measuring humidity is easy with a hygrometer, an inexpensive meter that you can use on each floor of your home, including the basement, to estimate the indoor humidity levels.
In addition to the natural moisture that might be contained in the air, humidity in your home comes from daily activities such as cleaning, cooking and bathing. Household members also emit humidity through breathing and perspiring. If you use natural gas for cooking, it will emit water vapor as part of the combustion process. A home with a lot of air leaks can let in outdoor humidity continually, as well as have higher heating and cooling bills. Leaking plumbing fixtures and appliances add water vapor to your home and contribute to mold growth and wood rot.
If you have any air leaks between your ceilings and the attic, humid air can rise in the winter, warming the attic. Should the warm, moist air rise to your roof decking, it can condense and drip onto whatever lies below and damage the decking material. Wet material in the attic can support mold growth, causing an expensive repair down the road, or permanent, irreparable damage to whatever you store in the attic.
A gas furnace can create humidity indoors, but only when it's malfunctioning. If you notice an increase of humidity when your furnace runs, contact your HVAC contractor immediately. Ventless kerosene or propane heaters can also emit carbon monoxide (CO) indoors and add humidity. They should never be used for a prolonged period without fresh air ventilation.
Problems Associated With High Humidity
Excessive humidity causes problems for the health of your home and all its occupants. High rates of water vapor indoors contribute to:
- Mold and mildew growth
- Wood rot
- Dust mite proliferation
- Peeling indoor paint
- Corrosion of certain metals
- Reduced indoor comfort during the summer
Humid air feels warmer than drier air. The U.S. Department of Energy's Energy Star program estimates that each degree you turn your air conditioner up results in up to 6 percent lower energy consumption, so it makes sense to reduce the humidity to improve your comfort.
You feel cooler in dry air because the moisture on your skin evaporates faster. Evaporating water takes a lot of energy from your body, and under humid conditions, it takes longer for your skin to dry which prolongs your discomfort.
Using the kitchen exhaust fan when cooking or baking with gas removes some of the humidity, as does running the bathroom fans when bathing. A dryer's vent hose should always be vented outdoors to prevent the excessive humidity coming off your clothes or CO poisoning if you use a gas dryer. Sealing air leaks will lower humidity, improve indoor air quality and reduce your energy bills.
Using an air conditioning system for dehumidification works, but turning the thermostat lower increases your electric bill as well as the wear and tear on your HVAC system.
Another way to keep your home's air fresher and less humid is with an energy recovery ventilator (ERV). These devices provide balanced air ventilation for your home and use technology that exchanges heat energy between inflowing and outflowing air, to aid in heating or cooling, depending on the season. The ERV, unlike its close cousin, the heat recovery ventilator, also exchanges moisture, so in the summer it will help dehumidify indoor air.
Two of the best approaches to dehumidification include portable dehumidifiers and whole-house systems. They contain a cooling coil over which the indoor air blows, and moisture in the air condenses before being removed.
Whole-house and portable dehumidifiers are designed to remove humidity by condensation. Portable dehumidifiers work well in small homes or individual rooms, but if you need more than one room to be dehumidified, the cost and inconvenience of portable models can add up. They require a fair amount of work to maintain, since they need to be manually drained and frequently cleaned. Some have automatic shut-off switches when the water container reaches a certain level.
A whole-house system attaches to your home's forced-air heating and cooling system and drains automatically into the home plumbing system. They turn on and off based on the humidity levels you set. A humidistat works just like a thermostat and you can set it to the level you want in your home.
Whole-house dehumidifier capacity is measured by testing the unit when the air temperature is 80 degrees F and humidity is at 60 percent. This measures the amount of water the device removes within a 24-hour period in pints or quarts.
The ability to remove water is often overstated for portable dehumidifiers since manufacturers tend to test them when humidity is 100 percent. At that humidity level, it's easy to remove water vapor, but their capacity when the humidity level is lower will be much less. Portable units also have to work harder to remove excess water vapor, which drives up your electric bills.
A portable dehumidifier is likely to be made from plastic and mounted on wheels so it can easily be moved around the house. Whole-house systems use more durable stainless steel or heavy-gauge plastic for their housing. Some have large ducts that pull in air and redistribute it throughout your home. These systems are plumbed directly into your home's drainage.
A whole-house dehumidification system carries a rating called CFM, or cubic feet per minute. This tells you how much air the dehumidifier moves. The HVAC contractor can tell you how many CFMs you need to comfortably dehumidify your home. Portable units do not have to disclose their CFM ratings, and the fans inside aren't capable of moving enough air except in individual rooms.
Humidity reacts to different temperatures. It's much more difficult to remove humidity from cooler air, and a portable system may struggle when temperatures fall below 60 degrees (which is the typical temperature for a basement). A portable system may run continually and not be able to remove enough moisture to make your basement air feel comfortable.
Portable systems aren't manufactured to be easy to repair if a part fails. In fact, replacement parts may be unavailable, and you will need to replace it with a new appliance once your warranty has expired. Whole-house dehumidifiers, on the other hand, are built sturdier and when a part fails, it can almost always be replaced.
A dehumidification system is also useful in the winter to dry your home out when cold fronts approach the area. Too much humidity indoors can result in condensation in your attic, the walls around water pipes, and on windows. According to the Michigan State University Extension Office, when the temperature is minus-15 degrees outside, the indoor humidity should not be more than 15 percent if you keep your home at 70 degrees and 18 percent if it's kept at 75 degrees.
When you leave your home in the summer for an extended period, you can also switch your cooling system off and leave the dehumidification system running, but only if it's a whole-house system. Portable systems need to be monitored daily. The air will circulate throughout your home and be comfortably dry when you return.
To learn more about the importance of dehumidification, contact Comfort24-7.com today. We provide HVAC services for homeowners in the Chicago area, along with northwest Indiana and southwest Michigan.