Insulation and ventilation can make the difference between an energy-efficient, unconditioned Conroe or Montgomery County attic and a zone of extreme heat that increases utility costs and decreases household comfort.
Unfortunately, attic insulation and ventilation in many homes are often lacking: The level of insulation was calculated for an era with lower energy costs and the passive ventilation design is generally not adequate to remove the heat load during summer.
Upgrading attic insulation and ventilation to fit the realities of 21st century energy prices and environmental concerns not only saves money but significantly improves household comfort.
Why insulation and ventilation are necessary
During summer, solar energy is absorbed through your roof and accumulates as heat trapped in your attic. On a hot day, attic heat can soar to more than 50 degrees above the outside temperature. Without adequate insulation and ventilation, living with a furnace just the other side of your ceiling has a number of disadvantages.
First, it's hard on your air-conditioning system and personal comfort. Rooms directly below a broiling attic can be as much as 10 degrees warmer due to conducted heat energy. This heat goes head-to-head with your air conditioner, increasing the home’s cooling load and making the A/C work overtime to meet thermostat settings.
Acute attic temperatures have another consequence. Years of summer heat can damage wooden structural members in the attic, particularly plywood roof sheathing, which may become heat-warped and cause exterior shingles to buckle. Insulation and ventilation keep heat out of living spaces and reduce attic temperatures to energy-efficient levels.
Attic heat infiltrates living spaces by conduction through your ceiling. Attic floor insulation retards downward heat conduction. However, the standard original insulation in attics was often as little as 3 inches deep. This is not sufficient to stop heat conduction that can increase utility costs significantly.
Fortunately, the attic is the easiest place in the home to add extra insulation. Here are some guidelines:
- First things first: Insulation does little to stop direct airflow. Seal any holes or cracks that admit air directly from the attic into living spaces before installing additional insulation.
- Insulation can be added directly atop existing insulation. It can be the same type as the existing insulation or a different type.
- Most attic insulation is either fiberglass batts — roll-out blankets pre-cut to fit in the spaces between ceiling joists — or cellulose loose-fill, pulverized paper or fabric that is blown into attic spaces with a large hose.
- For the climate in Conroe and Montgomery County, the Department of Energy recommends adding enough attic insulation to bring the R-value up to 38. This means a minimum of 11 inches of fiberglass or 8 inches of cellulose loose-fill.
Attic heat can be reduced by boosting the attic's passive ventilation. In most homes, attics are ventilated by air flowing in though vents in the soffits below the eaves, then naturally rising up and out of vents at the peak of the roof. Unfortunately, this passive method can't exhaust hot air fast enough to keep the heat down in summer.
Installing a powered attic fan on the roof augments passive circulation. Here's how it works:
- A powered fan on the roof draws a higher volume of air through the soffit vents and exhausts it faster. A properly-sized ventilation fan will exchange all attic air 10 times per hour, usually keeping attic temperatures below 100 degrees.
- The fan is operated by a thermal switch that turns on at a preset temperature in the attic. Attic heat is exhausted during hot summer months only, not in winter when it may help to warm the home.
- An attic fan will usually save enough in reduced energy costs to pay for itself in three years.
- An attic fan with a typical volume of 1,650 cubic feet per minute can ventilate an attic up to 3,200 square feet.
- Solar-powered attic fans incorporate a small photovoltaic panel to power the fan with energy from the sun. These fans have a higher up-front cost than wired attic fans but the payback is fast because they use no house electricity.
Serving the Conroe and Montgomery County area of Texas, Conroe Air Conditioning, Heating & Refrigeration offers homeowners superior products backed by solid expertise. Give us a call and let us answer all your questions about insulation and ventilation to reduce attic temperatures.