Glendale merv 13 filter cabinet upgrade: what the audit measures before the quote
Verdugo foothill homes face significant elevation gain so AC sizing must account for both inland heat and cool overnight pull-down; canyon morning fog common in winter That is the variable that turns a generic merv 13 filter cabinet upgrade into one engineered for the specific block. Average summer high near 89°F with winter low around 45°F at an elevation of 535 ft and roughly 17 miles inland. CEC Climate Zone 9. The cooling design temperature for Manual J calculations runs about 98°F, with typical Manual J load landing in the 350-480 sq ft per ton band. A design temperature of 98°F with the local diurnal swing means the inverter heat pump spends most of its operating hours near 30 percent capacity, and the equipment selected has to modulate down to that band without short-cycling.
ASHRAE 52.2-2017 sets MERV 13 minimums at E1 0.3–1.0 µm particles ≥50% capture, E2 1.0–3.0 µm ≥85%, E3 3.0–10.0 µm ≥90%. EPA verbatim: "Upgrade to MERV-13 or the highest-rated filter that the system fan and filter slot can accommodate." Smoke pencil or feeler-gauge bypass check at filter door perimeter, frame seal, and any cabinet seam.
Marcus Reyes, P.E. specifies based on the lowest bin hour, not the design day, because that is where the homeowner spends the actual operating cost. Electric service in Glendale is Glendale Water and Power (municipal); gas is SoCalGas. Equipment selection should match the rebate path that utility offers when the program applies on the day the contract is signed.