Pine pollen in March, catkins in April: filtration for Lake City houses, read off the electric bill first
A restrictive filter shows up on the FPL or Clay Electric bill before it shows up on the coil. Here is how to read it, and what to install instead.
What the bill says about your filter
Pull up the FPL or Clay Electric statement for a Lake City house and compare April against last April. If usage climbed and the weather did not, the filter is a leading suspect. Here is why: pine pollen starts in late February, oak catkins follow in April, and a one-inch grille filter loads up in two or three weeks. Once it is caked, the blower works against it, the coil runs colder and less efficiently, run times stretch and the bill rises. Many homeowners respond by buying a denser filter, which makes the restriction worse on day one. The bill is a filter gauge, and in spring it reads high.
The fix is not a better one-inch filter. It is more filter area, which means a deeper filter in a cabinet, and a blower that can breathe through it.
Retrofitting a cabinet into a 1978 block ranch near Lake DeSoto
Most of Lake City’s in-city housing was built between the 1950s and the 1980s, with the air handler in a garage or a hall closet and a single return. Fitting a four-inch media cabinet means cutting into the return plenum at the unit, which is routine when there is eighteen inches of clear space and a puzzle when the unit is jammed into a closet built for a smaller cabinet. On the tight ones we go the other way: a deep filter grille in the hallway ceiling, sized larger than the old one, which gives the same filter area without touching the closet. Either way the old one-inch slot gets sealed, because two filters in series is twice the restriction.
Building it into a Forest Cove new build
New houses in Forest Cove, Arbor Greene and Hunter Oaks come with whatever the builder’s mechanical contractor chose, which is usually a one-inch grille filter and a blower set to the factory default. The good news is the return is generally sized properly and there is room at the unit. A media cabinet goes in cleanly, and because these houses are tight, a better filter does more for them than it does for a leaky ranch where pollen comes in around the windows anyway. On a new build we also look at the fresh-air intake, if there is one, because unfiltered outdoor air in March defeats everything else.
Ask about a media filter cabinet
The duct realities: leaky returns pull pollen around the filter
A filter only cleans the air that passes through it. In a 1980s attic with original flex duct, the return side leaks, and every gap on the suction side pulls attic air, insulation fibers and pollen straight into the air handler downstream of the filter. We see it on the coil: a yellow-grey mat on a system whose filter looked fine. On manufactured homes the equivalent is the belly-board return under the floor, torn and open to the crawlspace. Before we sell a filter upgrade, we check the return duct, and on many Columbia County houses sealing it does more for the air than the filter does.
Sizing the filter to the blower, not the grille
The rule we work from is simple: the filter has to be large enough that the blower pulls through it with little resistance even when it is half loaded. That means matching filter area to the system’s airflow, which depends on tonnage, and verifying it with a static pressure reading before and after. A cabinet that is too small for the airflow is just an expensive one-inch filter. One sized right lets the blower run at its designed speed, keeps the coil clean through a yellow March, and takes the spring bump out of the April bill.
Filter questions from a yellow Lake City spring
How often should the filter change during pollen season here?
A one-inch grille filter, every two to three weeks from late February through April; it will be caked by then. A four-inch media filter in a cabinet goes three to six months even through spring, which is most of the argument for installing one.
Is a higher-rated filter always better?
Only if the system can pull air through it. A dense one-inch filter in a grille built for a cheap fiberglass pad chokes the blower, freezes coils and raises the bill. The rating has to match the filter area and the blower, which is what the cabinet solves.
Does the filter do anything about the smell from burn piles in winter?
A deep media filter catches a good share of smoke particles; a carbon-impregnated media filter does better on the odor itself. Neither replaces keeping the house closed and the fresh-air intake off on a burn day.
Where does the filter go on a manufactured home with a package unit?
Usually in a return grille inside the house, sometimes at the unit. On those homes we also check the belly duct, because pollen pulled in through a torn return run bypasses any filter you buy.
Tired of the yellow film on everything?
Call and tell us what filter you use now. We can usually tell you over the phone whether a cabinet will fit.