Air purification in the south Salt Lake Valley serves two distinct seasonal purposes. From November through February, it addresses the PCAPS inversion’s PM2.5 loading — the fine particulate matter that the Salt Lake Valley’s terrain and cold-air pool trap below approximately 5,000 feet for days at a time, producing outdoor air quality readings that regularly exceed the EPA NAAQS 24-hour standard during inversion events. From July through September, it addresses wildfire smoke particles from Intermountain West fire events that, on the worst days since 2017, have driven 24-hour PM2.5 readings at the Draper monitoring station above 150 µg/m³.
In both cases, the question is not whether particulate filtration improves indoor air quality during these events — it does, measurably. The questions are which filtration technology addresses the actual particle sizes present, what static pressure increase the air handler can handle, and whether the improved filtration addresses the primary IAQ driver or whether other interventions (humidification, source control) are more appropriate for the specific problem. We answer those questions before recommending equipment, not after selling it.
MERV (Minimum Efficiency Reporting Value) 13 pleated media filtration is the baseline air quality improvement we recommend for all Draper and south valley homes, before any additional air purification technology is considered. MERV 13 captures approximately 85–90% of particles in the 0.3–1.0 micron range — the size range that includes the majority of PCAPS inversion PM2.5 and wildfire smoke particles. MERV 13 does not require any separate power supply, does not produce ozone, and does not require any additional maintenance beyond filter replacement every 90–120 days.
The MERV 13 limitation is static pressure. A 1-inch MERV 13 pleated filter creates approximately 0.15–0.25 inches WC of resistance when new, increasing to 0.30–0.45 inches WC as it loads with particulate. For HVAC systems designed for MERV 8 filters (typical residential systems from the 1990s and 2000s), adding a MERV 13 filter may push total external static pressure above 0.5 inches WC, reducing airflow below the design CFM. We measure static pressure before and after every MERV 13 upgrade to confirm the system can handle the increased resistance. See our Air Filter Replacement page for the full MERV upgrade process.
For homes where the existing 1-inch filter slot cannot accommodate a MERV 13 filter without unacceptable static pressure increase, Aprilaire’s whole-home media air cleaner cabinets (Model 1210, 1610, 2410) provide a larger-format filter with more surface area. More filter surface area means lower face velocity through the media and lower pressure drop for the same or higher MERV rating. The Aprilaire 1610, for example, uses a 4-inch thick MERV 16 media filter in a cabinet with approximately 4 times the surface area of a standard 1-inch filter slot — producing a resistance of approximately 0.10–0.18 inches WC when new at MERV 16 efficiency, comparable to a MERV 8 filter in a standard 1-inch slot.
The Aprilaire 1610 at MERV 16 captures approximately 95% of 0.3–1.0 micron particles, 98% of 1.0–3.0 micron particles, and essentially 100% of particles above 3.0 microns. For a Draper household during a severe inversion event with outdoor PM2.5 at 65 µg/m³, a MERV 16 system reducing indoor PM2.5 by 95% produces an indoor level of approximately 3.25 µg/m³ — below the WHO 24-hour guideline of 15 µg/m³. The Aprilaire media air cleaner requires no power and no maintenance beyond annual filter replacement (the 4-inch media filter lasts approximately 12 months in our service area’s dust load conditions).
HEPA (High-Efficiency Particulate Air) filtration captures 99.97% of all particles at 0.3 microns, the most penetrating particle size in the HEPA test standard. True HEPA filtration is the highest particulate removal efficiency available in residential air purification. The limitation that prevents its universal application in HVAC systems is static pressure: a HEPA filter creates 0.8–1.5 inches WC of resistance, which is 2–3 times the maximum external static pressure most residential blowers can handle as a series filter in the main duct path.
The bypass cabinet installation solves this limitation. A HEPA bypass cabinet is plumbed in parallel to the main return air drop — not in series with it. A motorized damper (controlled by the thermostat fan signal or by a dedicated IAQ controller) opens the bypass path when the system is running, allowing a portion of the return air to be routed through the HEPA filter and back into the return plenum before reaching the air handler. The main duct path remains open, so the blower’s effective external static pressure is not significantly increased. Depending on the bypass cabinet’s cross-section and the main return duct’s cross-section, the HEPA bypass filters approximately 20–40% of the total return air volume on each pass, while the main path carries the remaining 60–80%.
Over multiple recirculation cycles during continuous fan operation, the cumulative HEPA removal effect is significant. Published data on bypass HEPA systems in residential settings suggests indoor PM2.5 reduction of 70–87% during continuous operation, depending on the bypass ratio and the home’s envelope tightness.
Who we specify HEPA bypass for:
The RGF Environmental Reme Halo is an in-duct photohydroionization (PHI) system that uses UV-C light and a catalyst to produce hydrogen peroxide plasma and ionized oxidants that circulate through the duct system and into the living space. The technology has documented effectiveness against certain volatile organic compounds (VOCs), odors, and some biological contaminants including mold spores and certain bacteria and viruses.
The Reme Halo’s mechanism is fundamentally different from filtration: rather than capturing particles, it generates reactive species that attack biological and chemical contaminants in the air and on surfaces. It is most appropriate for homes with VOC concerns (new construction off-gassing, chemical sensitivities, persistent odor issues) or biological contamination concerns beyond what UV-C coil irradiation addresses.
Important caveat on ionization technology: The Reme Halo and similar photohydroionization systems have been marketed with claims about virus neutralization that, while supported by some laboratory studies under controlled conditions, are not fully equivalent to real-world occupied space performance. We install Reme Halo systems for documented VOC and odor applications where the homeowner understands the technology’s established evidence base. For PM2.5 reduction during PCAPS inversions and wildfire smoke events, particle filtration (MERV 13, Aprilaire media, or HEPA bypass) remains the evidence-backed primary intervention.
The Carrier Performance Air Purifier (model GAPCCCAR and similar) combines a MERV 15 media filter with UV-C coil irradiation in a single cabinet. It provides both high-efficiency particle filtration and biological growth control on the evaporator coil surface in one integrated unit. For Carrier Infinity communicating system owners who want to add whole-home filtration and UV treatment through a single Carrier-branded unit with communicating system integration, the Carrier air purifier is an appropriate choice. We install and service these as Carrier Authorized Dealer.
Every air purification upgrade recommendation we make is conditioned on a static pressure measurement confirming the air handler can handle the increased filter resistance at the upgraded MERV rating. This is not optional. An air handler running at 0.45″ WC total external static with a MERV 8 filter cannot accept a MERV 13 filter upgrade without exceeding the 0.5″ WC design limit for residential blowers. Running a system at 0.7–0.9″ WC static pressure does not improve air quality — it reduces airflow below the design CFM, shortens blower motor life, reduces heat transfer efficiency across the coil, and can cause the furnace’s high-limit switch to trip.
The correct sequence: measure static pressure at the existing filter before recommending any upgrade. If the system is within the acceptable range for a MERV 13 upgrade (total external static below 0.35″ WC with the existing filter), the upgrade is straightforward. If total external static is above 0.35″ WC with the existing filter, we evaluate a larger-format Aprilaire media cabinet as an alternative that provides equivalent or better filtration efficiency with lower static pressure addition than a 1-inch MERV 13 in the existing slot.
Installation scope varies by product:
For whole-home air purifier installation across Draper, Sandy, Bluffdale, Riverton, South Jordan, and Herriman, contact us. We measure static pressure first, recommend the correct technology for your specific air quality concern, and install with before-and-after filter performance documentation.