I’ve lived in many houses, nearly all with A/C and all had filters in the return air duct. But the house I’m in now doesn’t have one. None of the houses in the development (built in 2004) have return air filters. Is this the normal practice now? Some newer houses have the huge filters 4 or 5 inches thick that you replace once a year but I’ve never seen a system without a filter before.

The inside of the unit (Rheem) is very dusty as is the duct work.

The air filter in my little apartment lives just behind the return duct vent at floor level. I know, it's a wierd set up, you would never know unless you are informed, it's quite a way from the furnance. The duct cleaning crews at work have reported wacky set ups too, they spot them on camera during initial inspections. If you haven't had the duct work cleaned recently, consider having it done, a good company can scope it out on camera, get to the bottom of the dilema. Then again, it's not unusual for builders to cut corners, save money by not installing a filter system, leave it up the the home buyer. It's not right on the part of the builder, home air quality affects your welfare, health and well being.

You need a filter. The dust will settle, condensation will turn it into concrete and it will plug up your AC

I find it hard to believe there is not a filter site designed into the return ducting somewhere. I think I'd start pulling covers off and looking or call someone familar with your unit arraingement.

Some units have the filter inside the blower housing part of the furnace or A\C air handler. Remove the blower cover to expose it.

When my subdivision was built, one of the builders took shortcuts and never made provisions for an air filter on the houses he built. I discovered it after climbing into the attic to see what size filters I would need when it came time to replace. The homeowner's association members put pressure on him and he quickly came around and replaced the 20 x 20 cold air return grill with one that was designed to hold a filter.

My Mom's house has her unit underneath in a crawl space and my brother who lives there just removed the filter to avoid crawling in to replace it. Like Jake_Dragon said, the dust plugged the A frame condenser/heat exchanger and it eventually developed mold in the unit.

Open up the front of your furnace. There should be a filter inside. If you're concerned about dust build-up in your ductwork put a filter behind the grill on all of you cold air returns. Unless the builder was more of an upper-end builder and wanted to make that a selling feature, he would not have put the extra filtering in and just went with the furnace filter.

Gary

My air return is in the ceiling return vent. I have to get out a ladder to reach it. I use high efficency air filters. I have been told that they no longer install ceiling returns. The AC guys said they could install a new filter in the air handling system that use hugh filters 4 inches thick that cost about $40 eah.

quote Originally posted by G-Man: Open up the front of your furnace. There should be a filter inside. If you're concerned about dust build-up in your ductwork put a filter behind the grill on all of you cold air returns. Unless the builder was more of an upper-end builder and wanted to make that a selling feature, he would not have put the extra filtering in and just went with the furnace filter. Gary

This is how mine works also, its at the furnace and not in the ducting.

quote Originally posted by G-Man: Open up the front of your furnace. There should be a filter inside. If you're concerned about dust build-up in your ductwork put a filter behind the grill on all of you cold air returns. Unless the builder was more of an upper-end builder and wanted to make that a selling feature, he would not have put the extra filtering in and just went with the furnace filter. Gary

Yeah, when I did HVAC work, I saw many systems that had a metal mesh just before the fan inside the furnace. You took bulk filter media and cut it to fit and attached it to the mesh. Others had filters that slid into the duct just before it fed into the furnace. There has to be a filter somewhere, so if there isn't one, be sure to add one.

Thanks to all for the replies.

The unit is a down draft Rheem RGLJ Series mounted on the garage floor of a two story house. There are two large return air vents, one upstairs and the other down. Neither return vent has a filter housing.



It seems the contractor cut corners when the houses were built, just like fierofool mentioned above. The filter housing is an option and it’s cheaper not to install one.



The new owner obtained this house on a short sale from lender and attempted to install a filter as shown below. This is a bad idea since the filter has to be bent to install it since the furnace exhaust pipe is located in front of the squirrel cage. There is no way to support the filter at the sides so it bypasses most of the return air. The center of the filter is blocked by the top of the squirrel cage housing which is the only support for the filter.



It’s probably too late to get any remedy from the builder who also apparently went bankrupt a few years ago. There are many vacant lots nearby where planned houses were never built. It’s really not my problem since I’m renting but it looks like some sheet metal work will be needed to fix this. Operation of the A/C will definitely be affected this summer by the dirt build up.

You'll probably have a bad dust problem in the house. The dust that's washed off by the condensate can also plug the condensate drain, causing water damage and mold to start to grow inside the unit. Dust or mold isn't good for the lungs.