I have noticed that the A.C. filters in many houses is in the ceiling.

What the fire truck is up with that that ?

At my daughter's house, she had two A.C. units.

I found one filter in the ceiling, but could not find the other filter.

Where can I look for the other air filter ?

On 7/6/15 10:54 PM, Andy wrote:
I have noticed that the A.C. filters in many houses is in the ceiling.

What the fire truck is up with that that ?

At my daughter's house, she had two A.C. units.

I found one filter in the ceiling, but could not find the other filter.

Where can I look for the other air filter ?

My filter is at the air-handler end of the return ducts, but most, I
believe, are at the living-space end. If I were looking for filters, I'd
go to the air handler to see where the return ducts originated.

On Monday, July 6, 2015 at 10:22:05 PM UTC-5, J Burns wrote:
On 7/6/15 10:54 PM, Andy wrote:
I have noticed that the A.C. filters in many houses is in the ceiling.

What the fire truck is up with that that ?

At my daughter's house, she had two A.C. units.

I found one filter in the ceiling, but could not find the other filter.

Where can I look for the other air filter ?

My filter is at the air-handler end of the return ducts, but most, I
believe, are at the living-space end. If I were looking for filters, I'd
go to the air handler to see where the return ducts originated.

I think the air handler is in the attic.

Could you be more specific ?

On Monday, July 6, 2015 at 11:31:32 PM UTC-5, Andy wrote:
On Monday, July 6, 2015 at 10:22:05 PM UTC-5, J Burns wrote:
On 7/6/15 10:54 PM, Andy wrote:
I have noticed that the A.C. filters in many houses is in the ceiling..

What the fire truck is up with that that ?

At my daughter's house, she had two A.C. units.

I found one filter in the ceiling, but could not find the other filter.

On 7/7/15 12:31 AM, Andy wrote:
On Monday, July 6, 2015 at 10:22:05 PM UTC-5, J Burns wrote:
On 7/6/15 10:54 PM, Andy wrote:
I have noticed that the A.C. filters in many houses is in the ceiling.

What the fire truck is up with that that ?

At my daughter's house, she had two A.C. units.

I found one filter in the ceiling, but could not find the other filter.

Where can I look for the other air filter ?

My filter is at the air-handler end of the return ducts, but most, I
believe, are at the living-space end. If I were looking for filters, I'd
go to the air handler to see where the return ducts originated.

I think the air handler is in the attic.

Could you be more specific ?

That explains why you found a filter in the ceiling.

AFAIK, the air handler is always on the return side of the evaporator.

Your return duct must run from the air handler to the ceiling filter
you found. If there are any forks, each duct leads to a different filter.

For example, I have floor returns in two rooms. Their ducts combine and
go to the air handler. My neighbor has a ceiling return in one room and
a return low in the wall in another room. Their ducts combine and go to
the air handler.

On Monday, July 6, 2015 at 11:22:05 PM UTC-4, J Burns wrote:
On 7/6/15 10:54 PM, Andy wrote:
I have noticed that the A.C. filters in many houses is in the ceiling.

What the fire truck is up with that that ?

At my daughter's house, she had two A.C. units.

I found one filter in the ceiling, but could not find the other filter.

Where can I look for the other air filter ?

My filter is at the air-handler end of the return ducts, but most, I
believe, are at the living-space end. If I were looking for filters, I'd
go to the air handler to see where the return ducts originated.

All the ones I've seen here in NJ are like yours, at the air handler.
That includes systems from the 50s through ones in new construction
today. One reason, would be there are multiple returns in a house
that would each need a filter, while at the air handler/furnace
you only need one. Also a lot of systems are going in with electrostatic.

On 7/7/15 9:09 AM, trader_4 wrote:
On Monday, July 6, 2015 at 11:22:05 PM UTC-4, J Burns wrote:
On 7/6/15 10:54 PM, Andy wrote:
I have noticed that the A.C. filters in many houses is in the ceiling.

What the fire truck is up with that that ?

At my daughter's house, she had two A.C. units.

I found one filter in the ceiling, but could not find the other filter.

Where can I look for the other air filter ?

My filter is at the air-handler end of the return ducts, but most, I
believe, are at the living-space end. If I were looking for filters, I'd
go to the air handler to see where the return ducts originated.

All the ones I've seen here in NJ are like yours, at the air handler.
That includes systems from the 50s through ones in new construction
today. One reason, would be there are multiple returns in a house
that would each need a filter, while at the air handler/furnace
you only need one. Also a lot of systems are going in with electrostatic.

The OP found a filter in the ceiling. That's why I assumed any other
filters would be accessible from living spaces, like my neighbor's.

I've looked closely at hers because she asks me to change filters. The
only other filter I remember is in mine. My house was heated by coal
grates for decades. Then oil stoves were added. Then a furnace took
over. Then an evaporator was put in the duct. I figured hers was more
likely to be typical, but with my lack of experience, it was a guess.

I was thinking of going to an electrostatic filter. Lately I read that
an HVAC filter doesn't make much difference in air quality because dust
spends most of its time on a surface like the floor, waiting to be
disturbed if you don't get it first with a vacuum.

On Wednesday, July 8, 2015 at 1:49:58 AM UTC-4, J Burns wrote:

I was thinking of going to an electrostatic filter. Lately I read that
an HVAC filter doesn't make much difference in air quality because dust
spends most of its time on a surface like the floor, waiting to be
disturbed if you don't get it first with a vacuum.

The purpose of the HVAC filter is to protect the air handler from dust. You need to keep the coils and fins clean or they don't transfer heat properly.

It has nothing to do with air quality or protection of people. You can get that kind of filter, but it is not standard.

On Wednesday, July 8, 2015 at 11:01:20 AM UTC-4, TimR wrote:
On Wednesday, July 8, 2015 at 1:49:58 AM UTC-4, J Burns wrote:

I was thinking of going to an electrostatic filter. Lately I read that
an HVAC filter doesn't make much difference in air quality because dust
spends most of its time on a surface like the floor, waiting to be
disturbed if you don't get it first with a vacuum.

The purpose of the HVAC filter is to protect the air handler from dust. You need to keep the coils and fins clean or they don't transfer heat properly.

Yes, if by HVAC filter you mean only the minimal filter that's
included with the airhandler. But
all kinds of filters are offered by the manufacturers and installed
as part of the system. IDK any install I've seen around here that
just use the 1" minimal one that's in the air handler.



It has nothing to do with air quality or protection of people. You can get that kind of filter, but it is not standard.

I guess that depends on your definition of standard. On new homes
going up here, electrostatic is widely used now.

On Wednesday, July 8, 2015 at 12:18:17 PM UTC-4, trader_4 wrote:
On Wednesday, July 8, 2015 at 11:01:20 AM UTC-4, TimR wrote:




The purpose of the HVAC filter is to protect the air handler from dust. You need to keep the coils and fins clean or they don't transfer heat properly.

Yes, if by HVAC filter you mean only the minimal filter that's
included with the airhandler. But
all kinds of filters are offered by the manufacturers and installed
as part of the system. IDK any install I've seen around here that
just use the 1" minimal one that's in the air handler.


The more filters you put in the path, the larger the pressure drop across them.

And that means your fan must be sized for that drop. I'd be cautious about adding something that might reduce capacity.

We did an operating room install some time back and that air did have to be clean.

On Wednesday, July 8, 2015 at 2:23:04 PM UTC-4, TimR wrote:
On Wednesday, July 8, 2015 at 12:18:17 PM UTC-4, trader_4 wrote:
On Wednesday, July 8, 2015 at 11:01:20 AM UTC-4, TimR wrote:




The purpose of the HVAC filter is to protect the air handler from dust. You need to keep the coils and fins clean or they don't transfer heat properly.

Yes, if by HVAC filter you mean only the minimal filter that's
included with the airhandler. But
all kinds of filters are offered by the manufacturers and installed
as part of the system. IDK any install I've seen around here that
just use the 1" minimal one that's in the air handler.


The more filters you put in the path, the larger the pressure drop across them.


You don't typically put more filters, you just put one good one
of whatever type you want.



And that means your fan must be sized for that drop. I'd be cautious about adding something that might reduce capacity.

We did an operating room install some time back and that air did have to be clean.

The air handlers I've seen on typical furnaces have been capable
of handling 5" media type filters, electrostatic (which have little
pressure drop). They are designed so they don't cause too much
pressure drop. I have a 5" one here on my 3 year old furnace,
nothing special about the blower. They are thick, but pleated
with a lot of surface area.