Air Quality is Only a Concern Outdoors, Isn't it?

Not true! The air inside your home can be even more of a concern to your health and comfort, especially in the winter. When cold, dry air enters your home and is warmed to room temperature, the relative humidity in the average house can drop to as little as 5%. Compare that to the average 25% relative humidity of the Sahara Desert and you can understand why the air inside your home can seriously affect your health and comfort. Since various studies have estimated that most people spend as much as 90% of their time at home indoors, there's reason to be concerned about indoor air quality.

What is "Relative Humidity" Anyway?

Relative humidity refers to the actual amount of moisture in the air expressed as a percentage of the amount of moisture the air is capable of holding.

This means that if the relative humidity of the air inside your home is 5%, the air has the capacity to hold 20 times more moisture than it contains. If the relative humidity is 100%, then the air is completely saturated with moisture. It's important to note that air will continue to add moisture (humidity) until it reaches its saturation point.

Temperature affects relative humidity, too. Warm air can hold more moisture than cold air. In the winter, when 30 degree outdoor air with a relative humidity of 50% enters your home and is heated to 70 degrees, its relative humidity plunges to just 12%. Without supplemental moisture your home quickly becomes "bone dry".

How Does Humidity Affect My Comfort?

Since the air in your home is always trying to reach its saturation point, it will absorb water wherever it's found. That means it is stealing moisture from the bodies of you and your children, your pets, your furniture and even your houseplants. By giving up moisture to the air, your skin, throat and nasal passages dry out and crack leading to various physical discomforts. That's why many doctors recommend humidifiers for allergy and asthma sufferers.

Research has show that 30 to 60% relative humidity is ideal. Outside this range bacteria, fungi, viruses and mites thrive and multiply. As these creatures increase in number, so does your risk of being adversely affected.

How Does Humidity Affect my House?

Virtually everything in your home made from wood contains some moisture. As dry air sucks that moisture out, the wood shrinks and cracks. Hardwood floors separate at the seams, furniture shrinks and cracks, and doors warp and no longer fit their frames as the moisture is drawn off.

Pianos, guitars and other wooden musical instruments also shrink from the loss of moisture and go out of tune. Maintaining proper humidity levels can eliminate frequent and costly re-tuning.

Perhaps the most annoying effect of dry indoor air is static shock. As you shuffle across a carpet or slide off upholstered furniture a static charge builds up in your body and results in that sudden, uncomfortable "zap" of electricity when you touch a piece of metal or other conductor.

Are There Any Benefits to Properly Conditioned Air?

Yes, it can help you save energy. Warm, humid summer air feels hotter than it actually is because of the moisture it contains. That same principle applies to your home in the winter. By keeping the relative humidity inside your home at an ideal level, you can turn your thermostat down a few degrees and still feel comfortable. Dialing down your thermostat just three degrees can reduce your heating bill by as much as five percent.

How Do I Know What's Right for Me?

General makes humidifiers in several different styles and capacities to fit most any central warm air heating system. Your General heating and air conditioning dealer will help you select exactly the equipment you need to assure a healthy, comfortable home for you and your family.

How Do Humidifiers Work?

All humidifiers for central forced warm air heating systems work on the same principle—as air is heated, it can and will absorb additional moisture from an evaporative media.

To humidify the air you need heat, air movement and the presence of water for evaporation. What sets General humidifiers apart is their efficiency and economy of operation in using this basic principle to add comfort to your home.

Forced warm air heating systems create a pressure differential between the cold air return and warm air supply sides of the furnace. Using this pressure differential and a bypass duct, a portion of the heated air from the furnace is diverted through a water-soaked pad in the humidifier cabinet. There, it absorbs additional moisture before returning to the heating system for distribution throughout your home.

In flow-through humidifier models, a solenoid valve meters water into a trough that disperses the water across the evaporator pad. General flow-through humidifiers use a patented water trough design that assures uniform dispersion of the water across the pad for maximum evaporative efficiency. Any unevaporated water drains from the bottom of the unit so there is less mineral build-up.

Installation Options

Flow-through humidifiers are installed on the vertical warm air supply or cold air return plenum.

Like flow-through humidifiers, reservoir or drum-type humidifiers rely on the normal pressure differential created in a forced warm air heating system to direct a portion of the heated air to the humidifier where it passes through a water-laden evaporator drum sleeve. The warm air absorbs additional moisture and then returns to the heating system for distribution throughout your home.

The polyurethane evaporator sleeve picks up moisture as it slowly rotates in a reservoir of water. An automatic float valve controls the water level in the reservoir.

Drum-type humidifiers are also installed on the vertical warm air supply or cold air return plenum. When there is no space for a plenum installation, a horizontal duct mount drum-type humidifier can be mounted in a warm air supply duct close to the furnace.

How much humidity does my home need?

How much humidity your home needs depends on its size and construction which affects the number of air changes experienced per hour. The more frequently the warm air in your home is replaced by colder, drier outside air, the greater the need for humidification.

The Air Conditioning and Refrigeration Institute, a non-profit trade association, developed and published the guidelines used by most contractors today. The guidelines classify home construction as "tight," "average" or "loose".

Tight homes have insulated walls and ceilings, vapor barriers and weather stripping around windows and doors. Windows and doors fit snugly and the fireplace has an effective damper. A tight home experiences about 1/2 air change per hour.

Average homes have insulated walls and ceilings, vapor barriers and a fireplace damper but loose storm doors and windows. Average homes experience one air change per hour.

Loose homes have little insulation, no vapor barriers, no weather stripping and no storm doors or windows. These homes typically experience two air changes per hour.

Your General heating and air conditioning dealer can help you choose the humidifier that's right for your home.

Why should I choose General humidifiers?

General's patented water tray design on flow-through models assures that the evaporator pad is moistened thoroughly and uniformly for greatest evaporative efficiency. With General humidifiers, more water gets into the air instead of running down the drain. You'll not only feel more comfortable but you'll save on your water bill as well.