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# Ventilation

### Ventilation Calculation

We count the intake area and exhaust area of your attic and determine if you need to move more air through your attic. Codes written in the past when energy was cheaper called for a 1/300 ratio of attic space to air flow. Or simply put 3 feet of air for every thousand square feet of air. That is 1.5 feet in 1.5 feet out. We believe this ratio should be doubled for the Texas heat. Texas is a hot climate and most energy dollars are spend cooling your house on hot days so moving 6 feet of air for every thousand square feet, that is 3 feet in 3 feet out will make your attic perform much better. Many homes are already designed with this higher ratio of air but we find so many problems with today's homes. In many cases, soffit channels along the base of the roof are often clogged by poorly installed baffle vents. Or the soffit vents themselves intended to be 12" X 6" has a 1" X 4" inch hole quickly cut by a skill saw. Sometimes time has clogged the soffit vents with dust or worn out the bearings on turbines. In other cases, turbines need to be added to peaks with no exhaust that trap air. Whatever your case may be we can provide a solution to move more air through your attic or repair the design items intended to move air through your attic, a CRUCIAL STEP in the Greenlows radiant barrier system.

Once we establish a plan, we can install one any of the following products:

## Exhaust Products

Wind Turbines

A time tested product that moves huge volumes of air out of your attic. Wind velocity and heat from below spin the turbine which pumps the hot air from your attic. They are relatively inexpensive and take no power to operate. This product is excellent for higher pitched attics with short linear ridges. The only drawback are the high winds that Texas gets in the fall/winter which can draw a lot of heat out of the home. But it's an excellent summertime exhaust mechanism because there is almost always a prevailing south wind.

Power Fans

Power fans, although they use electricity provide excellent heat reduction in the attic by moving air out of the attic at a much faster rate than natural heat movement. The key here is they must be installed properly, the thermostats set reasonably, and sufficient intake must exist or be installed so the power fan won't pull air from can lights or any other openings. An advantage of the power fan is normally it's the only exhaust hole in your roof so in the winter when it's not operating, heat stays in your attic much longer.

Solar Fans

An excellent choice for homeowners, solar fans provide rapid heat dissipation from moving air through the attic at a high rate for free. Several models have thermostats and backup AC power to run at night and on cloudy days or when the humidity gets too high in the attic. These are generally the most expensive product to install but offers the greatest benefits. If you chose to have us install one, opt for a thermostat so it doesn't run year round pulling unnecessary heat out of your attic and wearing out the motor in the winter.

Ridge Vents

A great product for long linear spans or lower pitched roofs with a lot of ridge space on the roof. Wind passes over the ridge vent and creates a circular pattern of air in the attic removing heat very effectively. The key is to have ENOUGH ridge space to justify it being more effective than some of the other products. Hip style roofs (triangular) that gather at a peak are generally NOT good candidates for ridge vents. We see roofs all over DFW where the roofer has recommended this product only to put 4-6 feet of it on because of the hip style design. That will create a lot of heat in the attic as exhaust is minimal. It's a product that is popular but must be installed on the right type of house to be effective.

Passive Vents

Passive Vents are essentially holes in your roof relying on mother nature to exhaust heat and moisture from your attic. Properly designed and balanced, they can be an effective system. Many home builders nearly saturate the attic with these products and make it difficult to install other systems because they can compete with one another.

## Intake Products

Soffit Vents

We normally must add or replace intake vents to homes to compensate for any exhaust adjustments we've made. Normally intake additions have the biggest impact on the temperature of an attic.

Baffle Vents

With so many high ceilings built in single story homes in DFW, we end up wrestling with poor intake in homes that weren't properly inspected. What happens is the 45 degree ceilings many times surround a home. These areas cannot be blown with loose fill insulation but rather must be filled with insulation batts to meet code. Well, baffle vents or "air tunnels" are rarely installed properly if at all and you end up with the eave areas not connected to the attic areas.