I believe that you are the member who sells furnace / AC filters.

Can you give us a short tutorial re MERV?

I was going to email that question to you, but then I thought maybe it might be of some interest to other members, as well.

I will need to order some filters, I use 18 x 18 x 1.

Out to lunch, be back soon.

Ok, lets start out with some general information first.
Proper airflow is the key to an efficient HVAC system, which will provide years of reliable service.

Low airflow, stresses the whole heating system. From over worked blower motors to excessive temps on venter assemblies and everything in between. Low airflow causes higher temperature rises across the heat exchangers. Not only stressing the components, but allowing hotter air to be exhausted. Costing money by lowing efficiencies.

So, if your system is already lacking return/supply ducting, adding a more restrictive filter will only cause further stress/damage to the system.

Another thing to look at is the filter's construction. Is it flimsy or will it hold up to the suction created by the blower? Too many times a cheap flimsy filter will be pulled out of the filter rack by the blowers suction. Allowing dust to bypass the filter. The evaporator for the cooling system now becomes the filter. When the coil becomes plugged, you now have a costly cleaning bill.

With compromised systems, a fiberglass filter is the best choice. Allowing for maximum airflow with the least restriction possible.

Sticking to 3/4" (x1) filters, I don't recommend going over MERV 8. Do to the fact they simply don't have the required media to allow for proper airflow.

Media filters (3-5" thick) are available for better filtration, to keep equipment operating at peak efficiencies or for someone who has allergies. The Trion Air Bear system is great for this at MERV 11. The extra media allows for better filtration, while allowing for proper airflow.

Higher MERV filters should only be used with media systems. As standard x1" filter racks don't allow for enough media to allow for proper airflow.

Filters cause more equipment failures than people realize. Cheap filter construction and high MERV filters are HVAC system killers.

A good media system is my recommendation for overall performance.

This message has been edited. Last edited by: Excam_Man,

OK, thanks. You have mail.

Ex cam thanks for the tutorial
One of the things we've been doing in our homes is installing multiple RA ducts. Typically one in each bedroom as well as one on each floor as a minimum. This allows us to install higher MERV filters as the velocity passing through each filter is reduced...

Multiple returns are always a good thing.

As long as the temperature rise and static pressures are within spec, you're good to go.

V you have mail.

With pleated filters you can go with a higher merv rating while still maintaining the same airflow and not creating more restriction. Here is a good article on filter types which is expanding on what EXCAM MAN is saying

http://aaaable.com/blog/unfiltered-look-ac-filters

You didn't mention the tonnage of your a/c unit, but my guess would be you have a 2 ton unit, since you never really see 1.5 ton units in FL. Each ton of a/c flows 400 CFM of airflow. 400 square inches is recommended per ton for the filter (if you want to run a Merv 11, Merv 13 with a 1" filter),but 250 square inches per ton is considered the very minimum size the filter should be. Generally a filter flows 2 CFM per square inch of filter, 18x18"= 324 square inches x2=648 CFM. Your filter size is proper for a 1.5 ton unit at optimal sizing, 2.5 tons at the very minimum sizing, but too small for anything larger. I'd stick with a Merv 6 flat panel or Merv 6-8 pleated in a 1" filter, if you have a 2.5 ton or larger unit. I've found that in Florida, the older homes typically have filter sizes either right at the limit or most times undersized for the unit (as well as return ductwork). In these cases it's usually best to stick with a Merv 6 filter OR Merv8 pleated as even a standard flat Merv 8 can be too restrictive.

I too get all filters made at wholesale prices right from the factory that makes them (pureair in Hollywood,fl) that is local here, but don't want to get into shipping or selling them. So stick with excam man for filters. But they make any size I want, Merv 6, Merv8, Merv 11 pleated 1", 4" filters etc. I get them for the houses I manage locally (one has 12 different filter sizes for the a/c's and all custom sizes).

The new houses I deal with (high end). Have bedroom doors that seal well so you don't get noise from other parts of the house. Each room has a return a little bit larger than the supply vent in the ceiling with a filter right there and the same size ductwork as the filter size (pretty much). It all goes to a big manifold and there is many times extra filter area compared to the CFM of the unit. It all works out very well, but the underside of the roof in the attic is foamed with insulation and the attic is sealed from the exterior (no vents) and air conditioned as well. But we're talking about a $10 million house that's 8,000 sq feet built in 2008. The other with similar a/c design is a $900k 1700 sq foot 3 bedroom house.

quote:

Originally posted by jimmy123x:
With pleated filters you can go with a higher merv rating while still maintaining the same airflow and not creating more restriction. Here is a good article on filter types which is expanding on what EXCAM MAN is saying.

Please don't put words in my mouth.

I stated "Higher MERV filters should only be used with media systems" and I stand by that.

Going to a high MERV pleated x1 filter is not a wise choice.

quote:

Originally posted by Excam_Man:

quote:

Originally posted by jimmy123x:
With pleated filters you can go with a higher merv rating while still maintaining the same airflow and not creating more restriction. Here is a good article on filter types which is expanding on what EXCAM MAN is saying.

Please don't put words in my mouth.

I stated "Higher MERV filters should only be used with media systems" and I stand by that.

Going to a high MERV pleated x1 filter is not a wise choice.

I'm not. Hence the PERIOD between the 2 sentences.

But, It depends on the setup. If you have much more filter area than necessary, that will flow 400 CFM versus the standard minimum 250 CFM, you can go to a pleated filter with a higher merv rating without restricting anything. A pleated filter by design has more surface area so it flows more air than a flat panel filter (all other things equal ie Merv rating, size etc.)

If you really want to measure if there's a restriction, simply put a vacuum gauge behind the filter and measure the vacuum.

If you want to start teaching, I suggest you find a student which has less knowledge about the subject at hand then yourself.

You know damn well what you was trying to do with the wording in your first 'paragraph'.

quote:

Originally posted by Excam_Man:
If you want to start teaching, I suggest you find a student which has less knowledge about the subject at hand then yourself.

You know damn well what you was trying to do with the wording in your first 'paragraph'.

Which was what exactly?

quote:

Originally posted by Excam_Man:
Media filters (3-5" thick) are available for better filtration, to keep equipment operating at peak efficiencies or for someone who has allergies. The Trion Air Bear system is great for this at MERV 11. The extra media allows for better filtration, while allowing for proper airflow.

Higher MERV filters should only be used with media systems. As standard x1" filter racks don't allow for enough media to allow for proper airflow.

We have an Aprilaire filter assembly attached to the furnace which uses Aprilaire 213 media (Model 2100 upgraded to a 2300?). How would one know if this could be upgraded to a Trion Air Bear system, and how the filtration would compare?

quote:

Originally posted by deepocean:

We have an Aprilaire filter assembly attached to the furnace which uses Aprilaire 213 media (Model 2100 upgraded to a 2300?). How would one know if this could be upgraded to a Trion Air Bear system, and how the filtration would compare?

Aprilaire is Trion's competitor. The 213 is a MERV 13 filter and is well suited for good filtration while allowing for proper airflow. There's really no need to change anything.

While I'm a big fan of Aprilaire Humidifiers, I've never been a fan of their 2100 media filters when it comes to replacing the accordion type media (The General AC-1 is even worse). The new 213 media has made this task easier.

The 20x25x5 Air Bear filter does fit/slide into the original 2100's plastic cartridge.

Excam_Man, thank you for taking the time to answer my question in detail. Thank you to V-Tail for posting this thread.

quote:

Originally posted by Excam_Man:
If you want to start teaching, I suggest you find a student which has less knowledge about the subject at hand then yourself.

You know damn well what you was trying to do with the wording in your first 'paragraph'.

What, you actually have the nerve to question the maven? You are actually challenging SIGforum's expert on everything? Don't you realize that the rowboat captain knows all?

Trying to get this ship back on course (see wht i did there? ;-))..

Excam I recently went to the IBS show in Orlando and had a nice long conversation with the Aprilaire guys about what to put in the very tight homes we build. We usually use an ERV to exchange air and the tech said that with their system of humidification control they have an outside air source but no exhaust....I looked at hi for a moment and said where does the air go?

He brought up a couple of interesting points:
1. You actually want to have a slight positive pressure in your house as that keep un-conditioned air from entering.
2. The air will escape through the dampers in your range hood and bath fans as well as when you open the doors...so you don't need to cut another hole in the thermal envelope...

Comments?

I'm trying to get the rep to come and talk with my HVAC guys here who are very good but this was something new to me.

The positive air is a good idea since it would keep the unfiltered air out. I am down wind of the Dulles Airport and the air is really dirty and bad for your health.

quote:

Originally posted by Excam_Man:

quote:

Originally posted by jimmy123x:
With pleated filters you can go with a higher merv rating while still maintaining the same airflow and not creating more restriction. Here is a good article on filter types which is expanding on what EXCAM MAN is saying.

Please don't put words in my mouth.

I stated "Higher MERV filters should only be used with media systems" and I stand by that.

Going to a high MERV pleated x1 filter is not a wise choice.

What is a media system??

quote:

Originally posted by Black92LX:

What is a media system??

An elaborate air filter/filter holder/rack.
3-5" thick filter enclosed in a nice sealing cabinet.

There's many companies manufacturing media filters/cabinets:

Trion
Aprilaire
Honeywell
General
Etc.

The filter material (media) is like an accordion. Allowing for maximum filtering efficiency while allowing for proper air flow (more media for air to pass through). The cabinet will have rails which hold the filter in place and will not allow airflow to bypass.

Here's Trion's lineup:
https://www.trioniaq.com/produ...idential_em_air_bear

Here's the filters which fit inside:
https://www.trioniaq.com/produ..._Parts_Media_Filters

Interesting.

So any way to correlate the MERV and the MPM (Microparticle Performance Rating)? IOW are those 1500MPR filters killing our system that otherwise has 1-2 returns per unit?