I do have two return ducts that do have filters. It is a fairly large room with that TV area to one side, a wet bar against one wall; and built in bunk beds against the other wall under the stairs. This is not the case, this have opposite effect. The more vents are open, and the larger and shorter the ducts the more load is on the motor and the less it flows after a point. Air filters can … If you’re not quite sure which air filter is the best fit for you, see Three Questions to Ask Before Buying Your Next Air Filter for additional help. If your furnace has speed control, it is likely a D/C motor. Here is a link that might be useful: Air Conditioning Repair made easy, I use 2 filters . . Usually there is not enough volume to keep the dust in the air long enough for the intake of the air conditioner to act like an air purifier. lowering/raising the ambient temperature. MERV ratings go right up to 15+, not seen on residential systems though as these are enhanced HEPA, that won't work on standard blower systems. Try the following DIY AC troubleshooting tips the next time you’re having AC issues: Check for a dirty air filter. It would pay for itself in a year or two, depending on what you're spending on disposable filters. The options are initially more expensive than replaceable filters, but they last many years. A lot of this discussion goes over my head and I'm trying to sort it out. I was thinking about buying a Merv 8 and a Merv 13 and putting them in series. The upper end of the passive filters includes some that are claimed to be roughly equivalent to a pleated filter, but not in the range of a HEPA filter or good microparticle filter. Putting in two filters might temporarily address the 2nd factor but it will have a negative impact on CFM and may, in fact, require that you replace the filters more often. It is a daylight basement that used to double as a single garage. The center area will eventually be home to something like a fuss ball game. If you have pets and dander is an issue, a MERV 11-13 will be much more effective at cleaning your indoor air. I have to disagree with Electric Motor Man. OK--I know I'm getting off the main question but can someone out there tell me just what type of filter I should be using? Don’t forget, some HVAC systems have a return in each room. Think of 1-inch pleated air filters as a fine fish net with a very small gaps: it catches everything from big to small fish, but that also means the net fills up with fish faster (say that 3 times fast). Soot can quickly turn your air filters black, leaving you surprised when you remove to filter to replace it with a clean one. Agreed. On the contrary, air filters are vital components to any HVAC or central air system that ensure your home’s air conditioner runs smoothly … Overtime this will put more strain on your entire central air unit including your blower, cost you more money on your utilities, and may cause premature failure. mini split for ac with rooom-to-room fans instead of central ac. You will still likely want to have your ducts cleaned. I would strongly recommend against using two filters at once, especially if it is just by reason of convenience. They capture nearly all of the largest particles, as well as most of the smallest ones. I warned that there might be more questions. Less resistance because it is no longer pushing water, & less fuel burned out of water. This causes [...] RPM to increase & the motor amp draw to decrease. These compressors are not cheap and neither will the labor to replace! Heat is a by product of conversions, and physically restricting airflow to a motor is actually equivalent to holding the motors fan blades, or the shaft from turning at all (that is an extreme condition, but "slowing it down" is not). You do trade the convenience of simple replacement for the need to wash them regularly, typically on the order of every month to every few months. The Filtrete Ultra filters do seem overkill and costly. Hence, the system is, working harder (strain) and using more energy. that's no different than using 1-2" filter which is done frequently although more often commercially. The result is a spike in the utility bill. If its really hot fans won't work. So there may be an air filter behind each of those return grills. Then when this is placed into a furnace by a furnace manufacturer, they are expected to (by good engineering practices) to rate the furnaces load capacity taking into consideration the MTBF (mean time between failure) rated (usually in hours) rating of the motor manufacturers blower hours. He said they were probably doing it to reduce the noise at the intake. Why you’re replacing your filter more often. 2 Wash reusable filters outdoors. The Merv 8 would catch the large particles and the Merv 13 would catch the smaller particles. I am in the process of buying a new home. I'll look into those filters! The only other intake that I can think of is the one in the main floor hall. Any thoughts for camouflaging window A/C units? The squirrel cage blower is designed to move a column of air, "restriction and if taken out of the unit and set in the open, then it would overload the motor. This seems odd to me. So the point here is, the more the motors operation is hindered, the more current is drawn, up to a point, because eventually the ever increasing heat from aforementioned HIGHER current draw causes the motor to burn out (or a protection circuit, either thermistor or speed controller safety) to shut down. This is the most efficient way of heating and cooling since you are not losing 30-50% in the ducts themselves. In either case, the furnaces with SPEED CONTROL, and A/C motors, are going to spin open ended (meaning no back pressure) at the highest rate of speed that the coils or controller is designed to operate at from the MOTOR manufacturers factory, until a controller steps this down *(if equipped as noted momentarily). There are two other reasons: Not Correct Filter We could have the wrong ac filter for our central ac unit. The more particulates that are trapped, the fewer get stuck to the interior of your vent work, and the better the airflow becomes. If you’d examine them with a magnifying glass, you’d find that one side is more porous than the other. Yes. You'd be much better off resolving the reason why you have Pet hair in you unit. Further restricting beyond this point will actually reduced air flow but the load on the motor will continue to be the minimum. )]. Thick filters, due to their increased surface area, also have other benefits like: Higher dust-holding ability (meaning it can catch a lot without blocking airflow) Longer life (most pleated 4-in and 5-in-deep media filters will Ductless A/C from Senville also act as heaters. If I apply NO power to a motor, and I crank it, it will excite a current in the windings and act as a generator. The living room has a gas fireplace. Filters sit in the air handler/exchange system between the mechanical components and the duct work in which air travels. Multi stage filtering is not a bad idea, and is done in many environments (especially commercially) for the same reason you asked, bringing only the pre-filtered air with whatever remains to the more expensive staged filter. I usually like to see them as close to the unit as possible. Don’t forget, some HVAC systems have a return in each room. It will also spin faster. Is this a good idea? In the basement on the other side of the big room? Most home central air units have only one air filter. Once enough air is restricted, being almost completely, then the motor can overheat as it relies on air flowing around the motor to keep it cool. (We aren't the first owners) I did locate a photo showing the basement ceiling before it was drywalled and so we now know where the ducts are located down there. actually 3 filters, if you count them all, I have a pair of the standard 1 inch filters on adjacent walls which lead into the air inlet chamber where there is an AprilAire whole house filter attached directly to the bottom of the furnace, The throw away filters catch the large junk and I change them every 3 or 4 months (more frequently in the A/C season) and that way the AprilAire lasts lots longer - 18 to 24 months in my case. Liquid could be returning to the compressor through the coolant lines which overtime will eventually cause the compressor to fail (3). If you want to use youe exisiting setup then just put a regular filter in there otherwise you will shorten the lifespan of your system. This is not the case, this have opposite effect. It will definitely have some measurable effect on CFM. I've found a LOT of disgusting things in there. If your air filter is in the return grille inside your home, then the arrow should point toward the wall or ceiling. Top floor bedroom? Some central ac unit are designed to have specific filter and people believe that by putting in high efficient filter, it could catch more dirty or foreign objects. I added that filter in the odor unit thus causing the air handler to run longer and in this case more efficient, If you can use 2 then use two and rotate and throw out first filter and add new one behind older filter as often as you need too, Click here to upload your image Home air conditioner filters are to be changed every 2 to 3 months, but it also depends on how often you use your air conditioning system.The general rule of thumb is not to wait for dust to settle and matte inside the filter. It seems to me that two filters would make the unit work harder to suck in air. In addition, furnaces (and central ACs) run only seasonally. Like rat hair, animal droppings, nuts, and dirt. Assuming your home also has an A/C condenser, there is also the risk of destroying the compressor. Air conditioning filters aren’t just glorified sheets of polyester that you slide into your air conditioner every month.  A MERV rating of 6 means the filter is 35% to 50% minimum efficient at capturing particles, sized 3.0-10.0 microns. A MERV rating of 7 means the filter is 50% to 70% minimum efficient at capturing particles, sized 3.0-10.0 microns. A MERV rating of 8 means the filter is 70% minimum efficient at capturing particles, sized 3.0-10.0 microns. A MERV rating of 11 means the filter is 85% minimum efficient at capturing particles, sized 3.0-10.0 microns. I suspect we all agree that restricting the airflow increases system runtime and that system runtime decreases system life, including and especially motors. Well, if airflow is restricted to the system, then less air flows throughout the house, therefore less cool/hot air is circulated through the system. I replaced two trane 20 year old system s with dual speed trane 18 seer. When you install a new air filter into the AC return duct, the arrows face inward to specify which way the air is flowing. HEPA filters are used in most home air purifying systems. Problems could include AC icing and furnace overheating. – Clogged Air Filter, Coils, or Obstruction in Front of Return Grille. Where do you live? It isn't clear what you mean here (e.g. Remember, this is the air … The MERV rating also indicates the percentage of particles the filter will remove from the air passing through it. And they also reduce a lot of airflow, thus reduce efficiency and put more strain on most systems (the Filtrete filters). . Conversion of A/C to magnetic motion, or to D/C and then Magnetic motion is NOT a 100% efficient process. Change your air filter every 3-months at a minimum, monthly if you have kids or pets, to avoid the thick buildup of air filter debris that can put a strain on your system. Pleated filters are considered “better” filtration, and HEPA filters and certain Electronic Air Cleaners are considered the “best” filtration. The filter in our central air/heat is directly under the unit and very difficult to replace filters. Bottom Line: Putting two air filters on a central air system will only have the net effect of producing a higher utility bill and reducing the lifespan of your central air unit. People often forget that air is matter & it has volume. Some motors have brushes, some don't, some have RPM controls, some dont, but in all cases, if a motor shaft is restricted from turning, it amounts to more current drawn, and as previously noted, less cooling too, in both cases, shortening the life of the motor and raising your electric bill. MERV 11-13 air filters are somewhat of a middle ground between the cheap ones and the more expensive ones. Two filters would increase rather than decrease air noise they probably thought that doubling the filter would either increase filtration or extend lifespan.You need to ask yourself what is most important to you if you are concerned with indoor air quality and you want to increase filtration then do it right and get a media filter that is properly sized for your equipment. It's a pain to replace them and pretty costly to replace them so frequently. (2) https://yorkcentraltechtalk.wordpress.com/2012/09/11/what-is-an-ecm-motor/ It's best to use just ONE filter of the right size. Take it from Alex Hertzog, our in-house air filter expert: “You need to verify which way the air flows, and the arrow should point in the direction the air is flowing. It's definitely not going to improve flow. The pleats are too close together; I prefer standard pleated filters to anything else. They are more effective than other mechanical air filters because they contain more fiber per square inch as compared to disposable fiberglass filters. So it is backwards from what most people think. A thicker filter (4-5 inches) has more surface area and therefore allows more room for air to pass through. If the system in question is regulated by a thermostat, then it logically follows, a priori & confirmed posteriori by you're truly, that the system will will have to work longer to achieve the same effect in a given environment to have the effect desired, i.e. Pleated air filters remove around 35 to 40% of the air pollutants at home. If the air is not flowing, briefly turn the fan on to verify the direction.” Like many, you may be wondering why the arrow should point in the direction the air flows. Therefore, it must work longer to move more air and achieve the desired temp. But yes, you can do that, and yes it will decrease flow, and yes that's ok. They capture the most air contaminants and should be replaced every 12-18 months. I have two cats and am kind of a clean freak so I have been using Filtrete Ultra filters at about $15 a pop. Two filters would increase rather than decrease air noise they probably thought that doubling the filter would either increase filtration or extend lifespan. They don't seem to be too restrictive, and the filtration is good. Bottom Line: Putting two filters will not make it last longer but may make you have to replace it earlier, assuming it doesn't already reduce air flow too much with just the filters. I'd recommend having your ducts cleaned and if your return air is near the floor, then make sure to keep that area a clean as possible. My thoughts on the OP question,try it, but it might be useful to pay for a duct cleaning. Professionals tend to recommend a return duct filter more often than a supply duct filter, but some believe no vent filter is the best scenario for any HVAC system because of increased air resistance.