Many factors contribute to the relative balance of air pressure in modern houses. Although it isn't necessary to understand the complex physics behind the concept of balanced air, it is important to understand the consequences of negative air pressure in your home.

How Air Becomes Unbalanced

Air pressure is never uniform throughout an entire house. It typically varies between rooms, and may be affected by forces as gentle as a breeze outside or warm air rising toward the ceiling on a cold day. More severe shifts in the balance of air pressure occur when using devices that pull air out of a house — most notably, burning wood in a traditional open fireplace.

When the pressure inside a house is greater than the pressure outside, it is called "positive." And conversely, when the pressure inside is less than that outside, it is called "negative." Clothes dryers, bathroom fans, range hoods, combustion furnaces, water heaters, woodstoves, and fireplaces all contribute to negative air pressure inside a home.

The harmful effects of negative pressure have become more apparent in modern "tight envelope" houses. Better engineering practices have resulted in homes that are more energy efficient (provided that heat energy is not lost through an open fireplace); however, there are several unintended side effects of an airtight structure.

The Symptoms Of Negative Air Pressure

The draft produced by a burning fire causes a suction effect on the house. As the fire consumes oxygen, the air in the room is pulled up the chimney, rapidly shifting the pressure balance in the room to negative. It is virtually impossible for any ventilation system to provide enough fresh "makeup" air to counterbalance the air pressure lost while using a traditional open fireplace.

Houses that experience unbalanced air pressure will show some or all of the following symptoms:

• Back drafting of combustion appliances, including fireplaces and woodstoves
• Stagnant, stale air, high humidity and condensation around windows or on walls
• Poor air quality, musty smell, lingering odors
• Mold and mildew
• A rush of air when opening an exterior door

Enjoy Balanced Air With A Condar Fireplace

In many modern houses, the number of air changes per hour is far below the standard recommended by health officials for air quality. The solution is to actively manage ventilation.

If you are building a new house with a wood-burning fireplace, the Condar Fireplace is an important component in the equation for a healthy home. In scientific terms, a Condar Fireplace is known as a "Zero-Sum System," meaning that any air pressure lost up the chimney is replaced by the outside intake. The process of balancing air pressure in the room is completely automatic. After installation, the Replenum starts automatically when a fire is lit, changes speeds as the fire gains or loses strength, and turns off as the heat dies down — delivering fresh makeup air to your home when it is needed most. And the Replenum's draft induction fan makes lighting your fire easy, regardless of the temperature outside.

Consider these benefits of a Condar Fireplace:

• Smokeless performance — guaranteed not to back draft
• Improved Indoor Air Quality (IAQ)
• Moisture reduction
• Dissipation of pollutants and odors
• Replacement of the air and oxygen consumed by heating appliances, fans, and other exhaust systems