3M Filtrete 1900 is a rare exception. MERV 13, yet low static pressure ratings when dirty.

The soilution is simple: just get a filter that is MERV 8 rated (at most!) and replace the filter(s) every 30 to 45 days. Guarantee your air conditioner will run way better.

What I never see is commentary on s system like mine. In a 2200sf house I have five filters on ceiling air returns throughout the house 2 20by20by1 and 3 14by14by 1. I usually use MERV 11 pleated filters as pollen is a concern here much of the year. Should I be concerned?

How do you get the access panel off with the drain trap connected?

Without a filter, my unit can take in 3400 CFM. With a MERV 5 3M Basic, that drops to 1800 CFM. Yikes. Hence I'm thinking about switching to the cheap Merv 4 fiberglass ones. All i want to do is protect the evaporator coils and blower. Merv 4 fiberglass isn't enough to protect my equipment?

1" 3M filtrete 1900 user here - merv 13, but also twice the media as most merv 8's on the market (1,560 sq. in) so they do not clog up fast, or create static pressure build up any faster then the typical merv 8. Oh, but they do collect smaller particulate matter MUCH better than any merv 8 on the market (including particulates from wildfire smoke) - which equates to cleaner coils, less work for your motor etc, and FAR better overall air quality in your home. My residential HVAC heating/cooling system (Maytag) is close to 20 yrs old. Other than changing out a pressure switch yrs ago, not a single issue. I change the 3M 1900 every 4-6 weeks in summer, 6-8 weeks when snow is on the ground.

Project Farm has performed a nice performance test with several different filters and the outcome may surprise you. I have been using 3m 1500/merv 12 filters for decades with zero issues on the hvac system. What these filters do quite nicely is cleans up the air in one's home. They are expensive and should be replaced Monthly or every two Months depending on how often your system runs. I will say my allergies and dust issue have been much better since going to these filters.

the more wind u want them go though the filter the less dirt will filter stop them, u want what result ? all depend on ur select.

i was checking one today it was reading .5. i guess we will go back soon 🙂

Never seen a liquid line dryer on a mini split line set before.?? EEV's are in the condenser unit.

Fiberglass low merv is the way to go for AC to ensure high airflow.

1" pleated filters are fine as long as they are properly sized for the amount of airflow. 16x25x1 is only good for up to about 1000 cfm and that is pushing it - beyond that, need a larger filter. They filter much better than fiberglass. The pressure drop depends on the specific filter and the air velocity through it.

Many homes are inherently bad and nothing can be done to reduce static pressure 😢

Even worse and more common, is horrible return duct and filter frame sizing. Fly by nighters completely ignore the return sizing the manufacturer recommends. Then you've got a S.P. problem no matter what filter you install. And it's expensive to fix. Flex duct, especially undersized flex duct, flows air poorly at best. But, it's the rule rather than the exception.

Ladies, this is how men think: our jobs mean this much to us. So, support your man in his job, and he WILL reciprocate at home. Make him feel bad about his job, and he'll just shutdown.

In my personal experience a dirty evaporate coil was more restrictive than a basic pleated filter. So much so that I got more airflow with pleated and a clean evaporator than I did was a dirty coil plus fiberglass filter.

How did all of the houses I work on as a remodeling contractor get 1” filters? From HVAC contractors. I’ve been running a Goodman 95 furnace with 1” Merv 13 filters for over 20 years. Not ideal but functional.

These fits drive me up a wall, i had one with a constant high superheat fault, missed the bulletin, turned iut the harness was corroded sending incorrect voltage to the EEV starving the evap.

So what filter or merv rating would you suggest getting?

I'm getting communication issues from a unit just installed, system works fine for about 12-14 hours then suddenly stops communicating with the thermostat. System comes back online after about an hour or so, this doesn't seem like the same problem you're showing but it's extremely frustrating that this is occurring. My AC guy hasn't got a solve for it yet

so what should a reaidential home have in their home? merv 5? 6?

lol. You probably use K&Ns on your internal combustion motors, too?

Three days after my 14 year old hvac was serviced it stopped cooling down the house. Same service company tech came to check system. He concluded that it was time for an new system and offered a quote to replace it. I later discovered he had put in a pleated filter three days earlier. I replaced it with a cheap blue filter. Three summers have passed and my 17 year old system works fine. Of course i've had a new hvac service provider for the past three years.

If people want to purify the air in their home, they need to buy an air purifier. The filters in a HVAC system exist to protect the HVAC system, not purify all the air in a home.

Just do a temperature rise test and if it falls within the furnace specs on the label you can take a nap.

Why no filter on the return vent ?

Depends on whats more important to you. Cleaner air or more air flow? I choose cleaner air. Nothing more important than my health. An HVAC system can be replaced when the time comes.

How does a MERV filter differ from other pleated filters?

Nothing wrong with pleated filters, as long has you combine them to get the proper surface area. As you know pressure drop is dependent on the air quantity you’re trying to push thru a given size filter. Simply put in a V filter arrangement instead of just putting one straight across the duct. I have a pleated filter media that is 4” or 5” thick. Plenty of surface area.

jusr replaced my 41 year old furnace one inch filters Lol

The problem with this video is most normies don't speak water column and cfm.... So it's only helping people who understand how a furnace works that probably already know that super restricted filters do more harm than good.

Bravo Sierra

i way way rather replace a blower motor OVER a FULL ac system i see system die alot more from being dirty and needing cleaning that leads to rust and leaks from dirtiness then i see blowers fail i almost never see blowers fail

On my main supply duct grill vent in the living room I'm getting the same cfm output reading using a digital anemometer. I get the same cfm reading whether I use a 4 inch deep filter or just standard 1 inch pleated. Would it be safe to say the 1 inch filter is ok?

Unfortunately many condos in the west coast use 1 inch. If you are not sensitive to allergies or other respiratory issues a basic dust 5 merv works great. 30 to 45 day change.

Sometimes not so silent. I was getting a whine, presumably from the blower motor, when using a high MERV pleated 1 inch filter. So I asked my HVAC guy about that and he confirmed I should use a MERV 4 (rock catcher), or be prepared to replace my blower motor MUCH earlier. If filtering for my health really needed at some point, I'll use some room air filter with a good rating for my bedroom.

What can you use to measure the pressure difference across the filter. I would like something that is permanently installed so you could judge how much resistance a new filter has and then as it got dirtier - when to change it.

Hi, SPN You call it static pressure, but isn't it really dynamic pressure, since you're measuring the pressure of air in motion, not standing still?

What could cause a comfort net thermostat to Lose communications with the network

This is way over my head. Can you please tell me what filter to use. Thanks

Great info, wish filter manufacturers would warn customers about the long term effects of using high MERV filters. Who am I kidding! They make a huge profits on the higher density filters that capture everything in sight but restrict air flow through the furnace. I switched from a MERV 13 to a MERV 8 filter years ago and saw a significant improvement in air flow, reduced noise and shorter heating and cooling cycles (increased off cycle time means more money saved). The last Rheem system I had ran for 24 years with no issues but I knew it was a matter of time before the repair bills started so I replaced it and only use MERV 8 filters. Obviously, you need something to keep all the airborne particles from collecting on the internal furnace components but it does not have to be an expensive April-wire unit or high end media filters.

If this needs to be done, I'm wondering why it's not done at factory? I was commissioning a fit system today and as soon as I'd hookup the Low voltage to outdoor unit, nothing would communicate anymore. Going back with proper service tools to diagnose and repair but wondering if it may be something to do with these switches.

Excellent explanation of downfalls of pleated filters. I'm wondering how many furnace manufacturers recommend, or supply pleated filters with their units. Appears HVAC repair people love the pleated ones, due to more frequent callbacks for repairs. Air distribution systems should be designed to provide the maximum exchange of air, be it heated or cooled. If there are no problems with allergies or excessive dust on surfaces, then why use anything like pleated that restrict air flow?

What do you think of aluminum washable electrostatic filters

Does this have a temperature offset?

Were you able to figure out the setup for heat pump three-and-a-half ton that can fit communicating. We are having issues with the unit keeping up in the cold temperatures period and customer likes changing temperature to cooler at night about 5 degree difference from daytime setpoint?

What is the pressure drop on the K and N washable Filter??? It's Merv 11 all I know..

as a HVAC journey person I found your video interesting. But IMO you are over stating the importance of static pressure which most home owner will not be able to measure or actually do anything about. Yes in a perfect world .5" would be great. You are terrifying them that the thousands of dollars they've spent on their furnace is being destroyed by a 1" filter. There are just too many factors to take into consideration to use a blanket statement like the title of your video. Duct design? AC? size of AC coil? Pets? Allergies? Cost?

Hi Static Pressure Nerd, I am hoping you can tell me if combining 4 - 1 inch filters (laying one on top of the other) would create the same effect as simply having 1 - 4 inch filter. I've been told that the more real estate a filter system has, the lower the static pressure. Thank you for your commitment to saving homeowners the terrifying expense of replacing their HVAC systems because of ignorance.

But the filter holder slots are only 1in 😩