What MERV filter should I use?

It depends on your blower and your duct system, not on preference. We measure static pressure with your current filter installed to see how much room you have. If the system is already restricted, moving up in MERV makes comfort and equipment life worse.

How often should I change my filter in Houston?

More often than the box suggests, because our systems run a large part of the year. A one inch filter in a house with pets often loads up early. Look at it monthly for a few months and you will learn your own house.

Will a better filter fix my musty smell?

Usually not. That smell is almost always biological growth on the wet evaporator coil or a condensate drain problem, and filtration reaches neither one. A good filter keeps a clean coil from fouling again. It does not clean a coil that is already dirty.

Are washable filters a good idea?

They rarely capture as much as a decent pleated filter, and they get reinstalled damp more often than anyone admits. A damp filter in front of a coil is not something we want in a Houston attic. Use a disposable pleated filter sized to your system.

Does a good filter make my AC last longer?

It keeps dust off the coil and blower wheel, and a clean coil transfers heat and drains better. That is a real mechanical benefit. It is not a substitute for annual service, and it is undone if the filter is so restrictive the blower fights it.

Air Filtration in Houston, TX

Air Filtration in Houston

Most homeowners are told to buy a better filter and left there. A filter has a tradeoff built into it: the more it catches, the harder your blower has to pull through it. Getting that balance right matters more than the number printed on the box.

What a filter is actually doing

A filter is a mechanical strainer. Air passes through pleated media and particles above a certain size get caught in the fibers. That is the whole mechanism, and it does nothing to air that never passes through it.

It has two jobs. One is capturing dust before it circulates. The other, which nobody mentions, is keeping your evaporator coil and blower wheel clean. A coil packed with dust loses capacity and holds moisture, and in a Houston attic that is exactly the condition that leads to biological growth on the coil and the musty smell that follows.

MERV, and the tradeoff nobody mentions

MERV rates how small a particle the media captures. Higher MERV catches finer particles and creates more resistance to airflow, and your blower was sized for a specific amount of resistance.

Put a high MERV one inch filter in a system designed around a basic one and you can measurably reduce airflow across the coil. That shows up as a coil running colder than it should, ice on the refrigerant lines, longer run times, and a blower working harder than it was built to. We measure total external static pressure before recommending a filter.

Why a media cabinet beats a better one inch filter

If you want finer filtration, the durable way to get it is more surface area, not denser media. A four or five inch media cabinet holds a much larger pleated filter, so the same volume of air passes through more slowly and resistance stays reasonable while capture improves.

Those filters also last longer between changes. The tradeoff is physical: the cabinet needs room at the air handler or in the return, and not every closet or attic platform has it.

Fit and bypass matter as much as the filter

A filter only works on the air that goes through it. If there is a gap around the frame, air takes the easy path around the media and the rating on the box stops meaning anything. We check the filter track, the slot cover, and the cabinet seams.

Return leakage is the other bypass. If your filter sits at the return grille in the hallway, every opening between that grille and the air handler pulls unfiltered attic air straight to the coil.

What we check on a filtration call

Filter size and fitWhether the filter seals in its track or air slips around the frame.
Static pressureTotal external static at the air handler, before and after a filter change.
Coil and blower wheelDust loading on the coil face and buildup on the blower blades.
Return duct integrityOpenings that let unfiltered attic air reach the coil.
Cabinet seamsGaps at the filter door and panel joints that create a bypass path.
Change intervalHow fast your filter actually loads, based on runtime and household dust.

Air Filtration, answered plainly

It depends on your blower and your duct system, not on preference. We measure static pressure with your current filter installed to see how much room you have. If the system is already restricted, moving up in MERV makes comfort and equipment life worse.
More often than the box suggests, because our systems run a large part of the year. A one inch filter in a house with pets often loads up early. Look at it monthly for a few months and you will learn your own house.
Usually not. That smell is almost always biological growth on the wet evaporator coil or a condensate drain problem, and filtration reaches neither one. A good filter keeps a clean coil from fouling again. It does not clean a coil that is already dirty.
They rarely capture as much as a decent pleated filter, and they get reinstalled damp more often than anyone admits. A damp filter in front of a coil is not something we want in a Houston attic. Use a disposable pleated filter sized to your system.
It keeps dust off the coil and blower wheel, and a clean coil transfers heat and drains better. That is a real mechanical benefit. It is not a substitute for annual service, and it is undone if the filter is so restrictive the blower fights it.