I don't know about saving money, but if your using a 1" filter, look out for the pleated ones (3M & Filtrete), as they are restrictive and will decrease airflow (increase static) and could damage your furnace.

Most duct systems are not properly designed for a more restrictive filter.

If, on the other hand, you want to have a 4 or 5" media filter installed, go ahead. They have much more surface area and very well give you better airflow.

V

I would say the more restrictive filters would be LESS efficient, in theory (less airflow).

Hum, makes me wonder if I misunderstood the bit on t.v. For a "proof" of filtering ability he poured table salt through the fiberglass (standard) filter, it went through, at least a lot of it did. None I could see went through the pleated filter.

I agree, more air resistance, less air, less heat transfer. My application is a heat pump, so the temperature change isn't large, perhaps 30 degrees when heating (as measured at the output side of the plenum compared to room temperature).

Now wait a minute. Are you telling mt 3 for $7 Natural Air pleated filters from HD are actually making my heat pump less efficient. I know they make a difference as far as home much dust goes through the house...we also have allergies. Still if the efficiency were a big issue, how could they get away with selling these...

I use the same filters Andrea. I see an advantage in standard pleated filters such as the ones we use, but the 3M Filtrete filters and the like are just too restrictive for many systems. I wouldn't be concerned with efficiency with using these filters. If you let them get very dirty, maybe. I was just saying that in theory, higher efficiency systems need to move plenty of air to stay efficient. Variable-speed blowers vary their speed to maintain CFM and maintain efficient operation.

Andre: Those filters are good.

I haven't seen the ad, but the only thing I could come up with is that the pleated filter (not too restrictive like a MERV 8) prevents dirt from forming on the indoor coil. A clean coil is more efficient than a dirty coil.

Thanks, good inputs.

So, how does one clean the indoor coils? I have a heat pump so I'm using them summer and winter. The opening for the filters gives some access to one side, but it is only a bit over 1" wide, so the home vacuum brush and hose will not fit in. Are there attachments one can buy for a standard tank-type home vacuum that can reach into narrow openings? My HP takes two filter, 14"x30"x1"

My HP has about 15 years of use on it, all with the low cost fiber glass filters, so I'm sure there could be some benefits from cleaning the coils. Is this a good service one might purchase from a heating/cooling contractor?

You need access to the underside of the coil where the air enters the coil. This side usually has more dirt deposited on it.

You can buy a self rinsing evaporator coil cleaning spray at an HVAC store, or a commercial supply store like Grainger. You spray the cleaner on the coil and the condensate from running the a/c rinses off the coil. Be careful with vacuum attachments - you don't want to bend the fine aluminum fins on the coil.

Good luck.

"Be careful with vacuum attachments - you don't want to bend the fine aluminum fins on the coil. "

Absolutely. You may want to hire a service contractor to perform a "tune-up" service and make certain they clean the coils as part of this service. The key to having a long system life is to keep it maintained well, so if you have not done so in a while you may want to have a service company out to do so.

We have 30 years HVAC experience in Atlanta area. I have tried many brands and types of filters. We recommend BoAir brand filters. They are electrostatic with no polyester...low air flow restriction and good dust arrestance. They are expensive but worth it.

I replaced my Waterfurnace Geothermal HP last november with a new unit. It uses a thicker pleated filter 2" I think. WF recomends changing once a year..maybe 6 mo, need to check before the cooling season starts. I think this filter list for about $100, wow, installer said equivalent filters can be purchased over the web for less than $50.....all from memory.

Furnace filters are rated by a MERV standard. The higher the number the more restrictive the filter. There is a balance point to every system where to tight a filter can harm the equipment by restricting air flow. The higher MERV units have to be designed into a system. Retrofitting them without being able to check the static pressure on the system is chancy.

You can save money by using a good filter and changing it regularly. I have seen a lot of equipment get blamed for failure when in fact there was 1/2" of dog/cat hair across the entire face of the filter. An extreme example, yes, but it is not that uncommon.

I would suggest a service call from a company where the coils are cleaned by a pro. Explain that you want a cleaning and system analysis. Have them measure the static on the system prior to and after the coil cleaning. Post cleaning is your benchmark number. Add the filter of your choice, MERV 8 or better, and remeasure. Your system is rated at an external pressure, probably .5". If you have low static you can add a higher MERV filter. make sure you let the Service Company know that you want a report on the findings. In fact, for this I'd be bird-dogging the guy. Be inquisitive, not a pain in the neck;)

Be aware that the devil is in the details here. Once you start looking at your duct system remember that the DOE says that the average residential duct system looses between 18-42% of its energy in duct losses.

Sorry you asked yet?

Different filters have different lifespans. A one inch furnace filter should be changed after a month of use while a 4 inch filter should be changed after 3 months. Conditions in your home can contribute to how often you should change your filter. More particles can be added to the air, which causes a strain on your filter and can shorten its life.

These conditions include:

- Dirty Duct work

- Pets

- Construction Work

- Burning Candles

- Tobacco Smoke

- Fireplace and Wood-burning Stove Smoke

Continuously running your furnace or air conditioning fan will helpclean the air in your home but could further shorten the life of your filter.