So how DOES the coils get dirty

[AvantGarde]

is it JUST from neglect of the filter

[TxDusty]

Not necessarily, If the filter is in a filter grille away from the unit any leak in the return duct can stop up a coil.

[diesel65]

Not just that, it is also caused by the filter not fitting correctly and leaks in the return duct after the filter or gaps in the cabinet.

[AvantGarde]

Not just that, it is also caused by the filter not fitting correctly and leaks in the return duct after the filter or gaps in the cabinet.

but muss up the coil losing long-term efficiency.

[TxDusty]

Or using the cheap blue filters that a bird could fly through.

[TxDusty]

There are alot of reasons why a coil gets dirty.The trick is keeping it clean along with the air in the house.

[diesel65]

but muss up the coil losing long-term efficiency.

Well now that just depends on where the leak is, if it is drawing in hot humid air (cooling) or cold outdoor air (heating) there is no energy gain short or long term.

I like to think of a duct system the same as I do the refrigerant circuit, = Closed, no leaks.

[alkydrinker]

Or using the cheap blue filters that a bird could fly through.

Unfortunately, Carrier provides a cheap blue filter that a bird could fly through with their air handlers and they say other ones will constrict air flow too much.

[lentz]

By not cleaning the house, buying a filter that you can read a newpaper through. Not changing it as often as you should. Burning candles. Dryer vent leaking in the house. A lot of cooking with out a power vented hood over the stove. Not having it serviced at least once a year. Make sure there is no leaks in the duct work. And don't forget if you have any kind of animals (Dogs or cats) or birds in the house. Everything get dirty if it is not taken care of. Even a HVAC Pro.

[woodsman]

Pets and cheap fiberglass filters are a recipe for a funky coil.

[hangfirew8]

is it JUST from neglect of the filter

In my case, it was hiring duct cleaners.

-HF

[wahoo]

I thought the reason that a person hired a duct cleaner was to clean the ducts and the coil??? There is more to this story I thinks!!!

[dash]

Unfortunately, Carrier provides a cheap blue filter that a bird could fly through with their air handlers and they say other ones will constrict air flow too much.

No ,they say the ducts must be sized correctly,if you want a better filter.

Tell me what brand's standard air handler comes with a better filter .