September 27, 2024
Indoor air pollution is a serious concern that can impact your short- and long-term health. There are two crucial aspects to improving indoor air quality in a home: air ventilation and filtration. Let’s explore the roles they play and the differences between them.
Air Ventilation
Air ventilation refers to the circulation of air through your home. A residence with good ventilation has an influx of fresh air. If you’ve ever noticed your air getting stale, it indicates inadequate ventilation. A primary benefit of good ventilation is that it dilutes the concentration of airborne pollutants and contaminants.
Natural Ventilation
Opening your windows and doors is one example of natural ventilation. There is also natural or passive ventilation that occurs unintentionally. This includes air that seeps in through gaps and cracks in windows, doors, walls, foundations, and so on. Builders construct modern homes with tight building envelopes. It’s highly effective for optimizing energy efficiency. The problem is that there’s little to no natural ventilation, which causes higher pollution concentrations.
Attic Ventilation
Passive or active attic ventilation has little effect on air quality. The purpose of this ventilation is to normalize the temperature between the attic and outdoor air. It makes heating and cooling a home more efficient.
Mechanical Ventilation
Mechanical ventilation provides active replenishment of fresh air. It often has some form of filtration to keep impurities out of the fresh air supply.
Central HVAC Air Handler
Central HVAC systems have an air handler that draws fresh air in, conditions it, and distributes it throughout the home. You only get this air when the heating or cooling runs unless you set the fan to “on.” These systems may not provide enough ventilation in newer homes. They’re designed to draw in only the air needed to cool or warm the home.
Whole-House Fan
Whole-house fans provide ample fresh air throughout an entire home. Your HVAC installer can help you choose a high enough airflow for the size of your home. Manufacturers design whole-house fans to run constantly, and it will smell and feel like you have all the windows open. Another advantage is that you usually won’t need to run your AC until later in the cooling season.
Recovery Ventilators
Recovery ventilators are advanced whole-house fans. A heat recovery ventilator (HRV) extracts heat energy from the exhausted air to preheat the incoming fresh air. This makes your heating more efficient. An energy recovery ventilator (ERV) does the same. An ERV also extracts moisture and transfers it to the incoming air to reduce dryness. This can offset the need for a furnace humidifier.
Air Filtration
No matter how much you dilute pollution in your home, there will still be some present. There’s ambient pollution from automobiles and industries that get inside our homes. We also introduce pollutants into our homes just by living life and through the cleaners and furnishings we buy. Air filtration is the process of removing or neutralizing remaining pollutants and contaminants.
HVAC Filter
One way that we filter the air in our homes is through our HVAC equipment. Central systems typically have a filter for each supply vent. Some may have a filter within the furnace instead. These are usually disposable filters that you swap out regularly. Ductless systems will instead have an air filter inside each indoor unit. These are typically washable filters that you replace once a year.
The industry rates filter effectiveness using the minimum efficiency reporting value (MERV). MERV is a scale with 1-rated filters providing the least filtration effectiveness and 16-rated filters providing the most. It’s good practice to use the highest MERV rating your HVAC system allows. Most modern systems support MERV 13, which will remove over 90% of household allergens. If you’re unsure, check with an HVAC technician. Using a filter with too high a MERV rating is detrimental. It restricts airflow into the system, which decreases efficiency, increases operating costs, and intensifies wear and tear.
Whole-House Air Filtration Systems
A whole-home air purification system provides filtered air throughout your entire home. In homes with ducts, we’ll install the air scrubber in the ducts. In homes without, we can install small dedicated ducts. In central systems, the ducts are on the return side of the system. Restricting airflow is much less of a concern, which allows us to use much stronger filtration.
Most air cleaners have mechanical filtration to remove particulate matter. Some systems will use a MERV 14-16 filter. Many will use a high-efficiency particulate air (HEPA) filter instead. HEPA filters trap at least 99% of the particles that pass through them. That includes large particulate matter like household allergens but also fine and ultrafine particles.
Many air purifiers pair the MERV or HEPA filter with activated charcoal. This human-made form of carbon is highly absorptive. It absorbs unpleasant smells and helps a home smell fresher. Activated charcoal also absorbs smoke, fumes, gases — including volatile organic compounds (VOCs) — and chemicals such as ammonia and formaldehyde.
There are alternatives to this traditional approach to air filtration. One example is an ionizer. It generates negatively charged particles that bind to pollutants and force them out of the air. An advantage to this approach is that the system can disperse these ionized molecules throughout the home. That means filtration can occur throughout the living spaces.
Humidity Control
Relative humidity (RH) plays a role in indoor air quality as well. The optimal RH is between 30% and 50%. If RH is too high, it can promote mold growth, elevate the concentration of some pollutants, and make breathing more difficult. If RH is too low, it can cause respiratory irritation and make you more prone to infections and illnesses. A whole-house dehumidifier helps to keep RH at or below 50% in summer. A whole-house humidifier helps to keep RH at or above 30% in winter.
UV Lamps
Ultraviolet (UV) lights give off a germicidal light. This is an approach to air filtration called ultraviolet germicidal irradiation (UVGI). UVGI neutralizes bacteria, viruses, and other pathogens. Some air purifiers have an integrated UV light. Most experts recommend a standalone UV light in your ducts. The UV lamp benefits from the slower air movement in the ducts. The mechanical and absorptive filtration benefit from the faster air movement within the air cleaner.
HVAC Zoning
Zoning is an approach to HVAC design through which we organize a home into separate areas. It lets you control heating, cooling, and ventilation in those zones independently. Zoning improves energy efficiency and lowers your short- and long-term HVAC costs. We can also integrate air purification and humidity control into a zoned system.
Do You Want to Upgrade Your Home’s Air Quality?
Scott-Lee Heating Company is a family-owned and -operated HVAC company that’s served the Greater St. Louis area for over 45 years. We offer both residential and commercial services. Our HVAC technicians install and replace furnaces, air-source and geothermal heat pumps, air conditioners, and ductless mini-splits.
We’re available around the clock for emergency repairs. Our team performs manufacturer-approved maintenance, and we offer a maintenance agreement that will save you money. We design, install, replace, and repair ductwork, including zoned systems. Our indoor air quality team specializes in ventilation, air purification, humidity control, and UV lamps. Call today or contact us online to schedule service or an in-home consultation for air filtration.