When wildfire season approaches, the first concern is probably about the family’s safety and whether one will have to evacuate their home.
However, people have probably also heard about the dangers of wildfire smoke to respiratory health. Even what seems like a little smoke can greatly impact the home and HVAC system.
This guide will explore wildfire smoke, how it affects the HVAC system, and how one can help reduce its impact on indoor air quality.
Wildfire Smoke
Wildfire smoke is a complex mixture of thousands of compounds, including gases
Wildfire smoke is a complex mixture of thousands of compounds, including gases, particulate matter, and water vapor.
The gases commonly found in wildfire smoke include carbon monoxide, carbon dioxide, methane, nitrogen oxides, and other volatile organic compounds (VOCs).
One of the most concerning components is fine particulate matter (PM2.5), which is made up of particles less than 2.5 micrometers in diameter. They are so small that they are invisible to the naked eye and can be inhaled deep into the lungs.
Fine particulate matter
These fine particles can include soot, acids like sulfuric acid, inorganic compounds
These fine particles can include soot, acids like sulfuric acid, inorganic compounds such as ammonium sulfate, metals like lead, and biological materials such as pollen and mold spores.
The specific composition and concentration of these contaminants vary based on what type of material is burning, including vegetation, buildings, and vehicles. Its composition is also affected by firefighting efforts.
While it’s true that water vapor makes up a significant portion of smoke, its role is not just as a carrier. Water vapor can interact with other particles, influencing the chemical reactions and transformations that occur within the smoke. The high water content in smoke can also contribute to its visibility and density.
Broader range of harmful compounds
Wildfire smoke is particularly concerning compared to regular smoke due to its intensity
Wildfire smoke is particularly concerning compared to regular smoke due to its intensity and the variety of materials burning.
Wildfires often consume a mix of vegetation and human-made materials, releasing a broader range of harmful compounds into the air.
Additionally, wildfires can produce smoke that travels long distances, affecting air quality over a wide area and exposing many people to its harmful effects. The combination of these factors makes wildfire smoke more hazardous and challenging to manage than smoke from more controlled or localized fires.
Dangers of Wildfire Smoke Inside
Wildfire smoke can enter the home through various means, the most significant being open doors
Wildfire smoke can enter the home through various means, the most significant being open doors and windows. Air leaks throughout the house, including gaps around doors, windows, and vents, can also permit smoke infiltration.
In addition to these openings, wildfire smoke can be carried indoors on clothing and pets. Smoke particles are tiny and can cling to fabrics and surfaces, making them easily transported inside.
Porous materials like furniture and carpets can absorb and later release these contaminants into the indoor air. Consider limiting the pet’s time outside and washing clothing when returning home during wildfire events.
Physical barriers
Physical barriers are essential for effectively sealing the home from wildfire smoke
Physical barriers are essential for effectively sealing the home from wildfire smoke. Start by inspecting the windows and doors for any visible cracks or gaps.
These can often be found along the edges or frames. Seal these openings with a high-quality caulk, such as silicone or polymer-based products. Be sure to apply the caulk evenly and smoothly for a complete seal.
Additionally, examine the weather stripping around the doors and windows. This material helps create a tight seal when they are closed. Over time, weather stripping can become worn or damaged, allowing smoke to seep through. If users find any issues, replace the weather stripping with new, high-quality material.
Checking for leaks
To check for cracks and leaks, users can perform a simple test by closing all the windows and doors and running a smoke pencil or incense stick around the edges.
If the smoke drifts through any gaps, those areas need additional sealing. Addressing these potential entry points can significantly reduce the amount of wildfire smoke that infiltrates the home, creating a safer indoor environment.
Ventilation
It’s essential to take measures to minimize smoke infiltration through the ventilation system
Ventilation is a crucial component of a home’s HVAC system, but it can also be a pathway for wildfire smoke to enter the home. During periods of heavy smoke, it’s essential to take measures to minimize smoke infiltration through the ventilation system.
Consider sealing exterior vents as a preventative measure when wildfire smoke levels are high. This can be done by installing vent covers or air-tight dampers.
Vent covers can be placed over exterior vents to block smoke from entering, while users can adjust air-tight dampers to reduce the amount of smoke that gets through the ventilation system.
Closing air-tight dampers
It is especially important to address vents more vulnerable to smoke infiltration
To close air-tight dampers, first locate the damper controls, which are usually found near the vents. Many dampers have manual levers or sliders that users can adjust to close the damper.
Alternatively, use the control panel or a remote to close the dampers in automated systems. If users need help operating the dampers, refer to the manufacturer’s instructions or consult a professional for assistance.
It is especially important to address vents more vulnerable to smoke infiltration, such as under-eave vents and those associated with mechanical systems like energy recovery ventilators (ERVs) and heat recovery ventilators (HRVs). These systems are designed to exchange indoor air with outdoor air, which can inadvertently bring smoke indoors.
HVAC System’s Air Filter
The air filter in the HVAC system is a critical component for improving a home’s air quality
The air filter in the HVAC system is a critical component for improving a home’s air quality, especially during wildfire events. Fine particulate matter in wildfire smoke can bypass standard air filters and enter the ductwork.
Air filters are rated based on their efficiency using the Minimum Efficiency Reporting Value (MERV) scale. Filters with a higher MERV rating are more efficient at trapping particles.
HEPA filters, which are at the high end of the efficiency spectrum, are rated MERV 17 or higher and can capture a significant amount of airborne contaminants. However, not all HVAC systems are compatible with HEPA filters.
Finding a suitable filter
To determine which filters are suitable for the system, consult with an HVAC technician
To determine which filters are suitable for the system, consult with an HVAC technician. They can recommend the highest efficiency filter that the system can accommodate.
Even if the system is incompatible with a HEPA filter, installing a high-efficiency filter will help remove as much contamination from wildfire smoke as possible.
During wildfire season, monitoring and maintaining the filter more frequently is essential. Smoke can quickly clog filters, reducing their effectiveness and blocking airflow. Plan to check the filter at least monthly, but consider inspecting it weekly when there is an active fire in the area. Replacing the filter more often may be necessary to ensure optimal air quality and system performance.
Maintenance is necessary
Maintenance is critical for a home’s HVAC system after wildfires. Even a high-quality air filter will not prevent some airborne contaminants from entering the equipment.
Call to schedule a cleaning and HVAC tune-up if one notices signs like reduced airflow from their vents, increased energy consumption, or more prolonged heating and cooling cycles.
