When creating an energy-efficient, airtight home through air sealing techniques, it’s very important to consider ventilation. Unless properly ventilated, an airtight home can seal in indoor air pollutants. Ventilation also helps control moisture—another important consideration for a healthy, energy-efficient home.
Your home needs ventilation—the exchange of indoor air with outdoor air—to reduce indoor pollutants, moisture, and odors. Contaminants such as formaldehyde, volatile organic compounds, and radon can accumulate in poorly ventilated homes, causing health problems. Excess moisture in a home can generate high humidity levels. High humidity levels can lead to mold growth and structural damage to your home.
To ensure adequate ventilation, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) says that a home’s living area should be ventilated at a rate of 0.35 air changes per hour or 15 cubic feet per person per minute, whichever is greater.
Proper roof ventilation and a properly insulated attic help keep your home energy efficient. To understand why they both work together, we must first understand why a home may be inefficient when it comes to the amount of energy it uses. Your WE Energies bill can tell you a lot about how efficient your home is. Talk to your neighbors and friends and see if your energy bills are higher than theirs. How do your homes compare? The heating/cooling elements of your home only turn on and run when the temperature of the home is not equal to the display on the thermostat. The more often the furnace or air conditioner has to run, the higher your energy bill becomes. When your home is fully insulated and properly ventilated, the energy bill is at a minimal level. So, if you are writing big checks to WE Energies, and are tired of doing so, it is time to make improvements to your home.
Another tell tale sign that your attic needs more insulation or your roof needs to be better ventilated is the temperature in your home. Is the second story of your home warmer than the first? This is caused by the sun beating down on the roof all day long. Without proper ventilation and insulation, the warmth from the sun enters your home and battles with your heating and cooling system, ultimately winning the battle of the second floor. Your first floor may seem colder than your thermostat reads, or the second floor may seem like a boiler room. The reverse happens in the winter months, when snow covers the roof and makes the attic colder than the rest of the home. Taking measures to properly insulate your attic and vent your roof can significantly reduce the temperature difference between the first and second floors of your home.
Proper roof ventilation is comprised of the correct ratio of both intake and exhaust to create air circulation in and out of the air space being ventilated. There are a number of ways that proper roof ventilation can be achieved and each have advantages and disadvantages. The size and shape of the roof, objects such as trees and other structures, all contribute to factors of consideration when designing and deciding on best solutions for proper ventilation. Incorrect air flow can prevent the ventilation process from occurring and have serious consequences. Lack of proper ventilation leads to higher energy bills and moisture build up in attic eventually leading to warping, splitting, cracking structural defects and generally damaged roofs. Most roofing product manufacturers void all warranties if proper ventilation according to specified standards is not in place due to probability of premature product failures. Proper ventilation systems will affect the life of the roof system by 25% or more.
A ventilated roof will also help keep rotting and warping of siding as well as mildew, drywall damage, and peeling paint both inside and out. It also keeps moisture from being trapped in structural wood, insulation, and shingles.
When the roof is properly ventilated, it allows air to flow naturally into the attic, and back out again. It also prevents excess heat and moisture to accumulate in the attic, which would lead to the need for a new roof earlier than planned if contained in the attic for extended periods of time.
Having a properly ventilated roof allows your home to breathe. When the excessive temperatures are released from the home instead of into the living areas of your home, it keeps the temperature of the home at a stable level throughout the house. This reduces the need for your heating/cooling system to be used, in turn reducing the energy your home needs to function.