Even in homes without any obvious indoor air quality (IAQ) issues, taking steps to improve the air filtration could benefit the long-term health of all family members. Since newer homes are much more airtight than in the past, improving IAQ has become even more important for a safe and comfortable home.
In a home with little air infiltration, volatile organic compounds (VOCs) can build, along with concentrations of dust, mold spores, pet dander and other elements that have the potential to create short- and long-term health problems. The U.S. EPA reports that indoor air can be much more polluted than the air outside.
Fortunately, you can use devices and systems in conjunction with your HVAC system to maintain healthy air.
The HVAC industry has developed energy recovery ventilators (ERVs) and heat recovery ventilators (HRVs) that pull in fresh air while pushing out stale, indoor air. These devices contain a heat exchanger that transfers the energy from the outgoing to the incoming air, and vice versa depending on the season. This prevents you from wasting energy (and money) like you would with conventional air leaks. An ERV will also transfer moisture between the inflowing and outflowing air while trapping airborne particulates in a filter.
Fresh air year-round will dilute the minor and serious threats that VOCs and stale air pose. VOCs come from cleaning products, air fresheners, carpeting, furniture, shower curtains, dry cleaning and paint, among others. An ERV will keep the air cleaner and healthier by eliminating any hazardous VOC residues that may cause ill effects.
Another way to improve indoor air quality if your home has an attached garage is with an exhaust fan that’s installed in an exterior wall. When you store your motor vehicle, pool or yard chemicals, or common home improvement or cleaning products in an attached garage, they can release their gases into that space. If the door to your home doesn’t seal tightly or there are cracks in the common wall, those fumes can enter your home. Ductwork that runs through the attic also can pull those fumes indoors if the ducts have any leaks or tears.
Your HVAC system filters the air each time it runs, which improves indoor air quality to the degree of the filter rating. As a result, it could allow smaller particles to pass through the filter. Residential air filters carry ratings that guide you by the size of the particles they trap. MERV (Minimum Efficiency Reporting Value) ratings are awarded on a scale from 1 to 16, with 16 capturing the smallest (and most) airborne particulates.
The maximum MERV rated filter you can use with an older HVAC system should not exceed 7 or 8, while newer equipment may be able to handle a filter up to 12 MERV. Before selecting a filter with such a high rating, check the owner’s manual or consult your HVAC contractor. Filters that are too dense will slow airflow through the air handler, which can damage your system as much running it with clogged filters. If you choose a higher rated filter, check it regularly; it will trap more particulates faster than a lower-rated filter.
For people with severe allergies, asthma or a compromised respiratory system, the best way to improve indoor air quality is with HEPA (High Efficiency Particulate Air) filtration. These filters are rated between 17 and 20 MERV and trap 99.9 percent of particles 0.3 microns and larger. HEPA filters are so effective because they combine different methods for trapping and arresting particulates. They can even stop bacteria and viruses.
However, they’re too dense and thick to use in a regular residential HVAC system without mechanically boosting airflow, and a whole-house HEPA filtration system requires professional installation. They have a supplemental fan that pulls the precise amount of air through the filter that your HVAC system needs to run efficiently. HEPA filters need to be replaced periodically depending on the indoor particulate load, typically once a year. Some come with carbon filters that help remove odors from your home. As effective as HEPA filters are, they won’t be able to remove all the particulates from smoke or eliminate all odors.
Mid to High MERV Filtration
Unless you need extensive filtration to improve indoor air quality, you might consider using MERV 8-10 filters. This type of filtration isn’t as costly in the short- or long-term and doesn’t require boosting airflow for the air handler. These pleated filters use increased surface area as part of their design to trap more particles. They provide a nice balance between maintaining system airflow and indoor air quality, without requiring system modifications.
Ultraviolet (UV) lights will reduce the population of mold spores and other organic microorganisms in your home. UV lights imitate sunshine and alter the DNA of bacteria, viruses and mold, keeping them from reproducing. They’re often used in health-care settings, public buildings and restaurants to improve indoor air quality.
HVAC contractors place the lights in the ductwork or near the air handler. The lights will keep the air handler’s evaporator coil free from mold growth or bacteria. In the summer, humidity from your home condenses on the cold evaporator coil and drips into the drain pan. If the water doesn’t drain or dry fast enough, it’s the perfect environment for mold and bacteria to grow. If you use a heat pump, these substances collecting on the coil will interfere with heating as well as cooling, since the pump circulates hot refrigerant through it in order to warm your home.
Humidifiers and Dehumidifiers
Dry air in the winter is common with forced-air heating systems. When the humidity level falls below 30 percent, your risk for infectious disease transmission increases, along with skin and respiratory issues. Static electricity, which is more common in dry air situations, can damage electronics, and prolonged dry air conditions can make wood shrink or crack. A whole-house humidifier solves the problems associated with dry air during the heating season.
The opposite holds true during the summer time, when humidity levels rise. You can take a burden off your cooling system and improve indoor air quality with a central dehumidifier. Humid air feels warmer and contributes to faster rates of mold growth and dust mites. You may be able to raise the thermostat when you combine a dehumidifier with your air conditioner.
Smoke and carbon monoxide (CO) alarms are crucial to your family’s safety, and while smoke may be readily apparent in your home by sight and smell, CO is not. If you use any combustion appliances or have an attached garage, you may be exposed to CO year-round. Underwriters Laboratory (UL) standards requires that a standard CO detector sounds an alarm when CO levels in the air reach 70 parts per million (ppm) within one to four hours.
However, even if the threshold never reaches 70 ppm, people in your home could experience continual exposure to this extremely dangerous gas. People with heart conditions and who are pregnant are especially sensitive to CO. One way to monitor the air for its presence is with a hard-wired or plug-in monitor that shows what the levels are over timed intervals. These types will also help you learn when your gas appliances malfunction so that you can take immediate steps to repair or replace them.
To learn more about any of these ways to improve indoor air quality, contact the pros at Byrd Heating and Air Conditioning. We’ve provided HVAC and air quality services for homeowners in Garden City, Savannah and Tremont Park since 1986.
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