Frequently Asked Questions
(Portable Indoor Air Cleaners and Purifiers)

We recommend that you read our webpage on air cleaner technology for a basic understanding of air cleaning methods.

1. How often should the filters be replaced?

   Many of the air cleaners use media filters: a) prefilter, b)primary particulate filter, c)gas/odor filter. 

   The prefilter is usually a low efficiency material used to trap large particles and to protect the primary filter(s).  Some sort of maintenance should be performed about once a month.  This may entail simply vacuuming the prefilter from the outside of the machine, or removing the prefilter and lightly vacuuming it, or rinsing the prefilter, or replacing the prefilter.  If the prefilter becomes damaged in the process of cleaning it then replacement is required in order to preserve the integrity of the primary filter(s).  Always vacuum the prefilter to remove the debris in the opposite direction that it entered the prefilter.  Never vacuum in a way that would pull the debris further into the prefilter.

   The primary particulate filter which is often a HEPA filter and the gas/odor filter consisting usually of carbon or a carbon blend can only be replaced as required.  They cannot be vacuumed.  Typically a HEPA filter will last 2-3 years under normal residential/small office use and the gas/odor filter will last about 1-2 years.  Of course the replacement interval will be dependent on the actual operating conditions and the degree of pollution present.

2. How do I know when it is time to change the filters?

   The best way to determine whether a filter change is needed is by measuring the pressure across the filters.  Unfortunately, portable machines are generally not outfitted with pressure gauges.  Pressure gauges tend to be reserved for pricier equipment in the industrial and sometimes commercial categories.   Therefore, since the equipment does not have a pressure gauge the actual determination is a subjective one.  If the filter(s) have been in use roughly the recommended time (see question #1) and the airflow appears to have dropped off then a primary filter change should be considered.  If the machine is emitting a pungent odor then it may be time to change the gas/odor filter because it may be saturated.

3. How much do replacement filters cost?

   Please enter our store for replacement filter pricing.

   Note that certain filters may be covered under warranty.
   warranty examples

4. I'm confused.  Please compare the HM-400 Standard, HEGA 2.1, and Allergy Machine.

   The HEGA 2.1 and the HM-400 Standard are the same machine except for the nature of the carbon section of the machines and orientation of filters.

   Both the HM-400 Standard and the HEGA 2.1 have prefilters and HEPA filters and they both use the same chassis, motor, and blower.  The HM-400 has granular carbon/zeolite.  The HEGA 2.1 machine has 100% carbon fabric.   Also, the air flows through the granular carbon in the HM-400 Standard before the HEPA filter.  In the HEGA 2.1 the air flows through the HEPA filter before the carbon fabric.  It is preferred to have the air flow through the HEPA filter first since the HEPA filter has more surface area than the carbon and particulates such as dust are less likely to clog the filter.

   The "Allergy Machine" is identical to a HEGA 2.1 machine in the color silver.   HEGA 2.1 machines are available in several colors but only the "Allergy Machine" is silver and is labeled as the "Allergy Machine." The HEGA 2.1 and Allergy Machine are identical in every respect except for color and labeling. 

5. I ordered a HEGA 2.1 but I think I received a Standard HM-400 instead. How do I determine which model I actually received?

   The Standard module inside the machine, has metal end caps and the HEGA module has cardboard endcaps.  Also, the Standard module weighs about 18 lbs. whereas the HEGA 2.1 module weighs about 8 lbs.   Between these two characteristics 1- type of endcaps and 2- weight, you should be able to conclusively determine if you received the proper model as ordered.

6. I ordered a HM-400 Plus model. How do I know I received the proper model?

   The HM-400 Plus model will have the letters "SB" in the serial number to designate the machine as "Super Blend."

7. What is the difference between the Healthmate models HM-400 Standard, HM-400 Plus, HEGA 2.1, Allergy Machine, HM-200, and MiracleAir model PM-400?

• These machines use advanced technology well accepted by the medical establishment for the removal of airborne allergens and volatile organic chemicals which may impact people with allergies, asthma, and multiple chemical sensitivities.  They are fabricated from sheet metal to reduce outgassing and noise and they incorporate high quality components.

• All 5 air cleaners contain a prefilter to remove large visible particles from the air.

• All 5 air cleaners contain true HEPA filters with efficiencies of 99.97%@0.3 u DOP

• All 5 air cleaners contain sorbent media, consisting primarily of carbon, to remove volatile organic chemicals, gases, fumes, and odors from the air.

• Only one of the models processes air at the rate of 400 cubic feet per minute(CFM) with the filters installed:  PM-400.  The HM-400 STD, HM-400PLS, & HEGA process air at 275 CFM with the filters installed. The HM-200 runs at half the rate or 137 CFM with the filters installed.

Using HEPA technology in portable air cleaners, it has been empirically determined that processing an amount of air equivalent to 6 room volumes per hour produces excellent air quality results. Therefore, at 400 CFM an air cleaner can process 4000 cuft. 6 times each hour or once every 10 minutes.  This is the recommended air cleaning rate for a typical residence or small office.  If there are sources actively emitting pollutants into the air than a higher air cleaning rate of 8 or 10 air changes per hour may be necessary. Note: Beware that you should make sure you know the number of times a machine will clean the air per hour when you read a claim from a manufacturer that a machine will clean a particular size area.  In addition, you should confirm that the machine processes the stated amount of air with the filters installed.  Some manufacturers quote free flow air processing rates in their literature, which are rates without the filters installed.  Quoting rates without the filters installed does not provide the information necessary to make an informed purchasing decision.

• The following table illustrates the compositions of the various sorbent media in the air cleaners:

* The manufacturer of the PM-400 indicates that zeolite does not have much effect on the removal of gaseous products.  Therefore, a decision was made to eliminate zeolite from the air cleaner.  They feel that zeolite is acting as a filler because it has little benefit and is considerably less expensive than the other constituents of the sorbent media.

• Weight - Of all the machines, with the exception of the HM-200, the HEGA is about 13 lbs. lighter due to the use of carbon fiber thread instead of granular carbon.

• Only the PM-400 and HEGA 2.1 place the HEPA filter in the air flow prior to the carbon.  This is important because the HEPA filter is pleated and presents much more surface area than carbon for collection of particulates such as dust, smoke, pollen, etc.  The large surface area means that there is less likelihood the airflow will clog.

• Only the PM-400 has independently installed HEPA and sorbent media that may be replaced individually.

• The HM-400 PLS, HM-400 STD, HEGA 2.1, and HM-200 are covered by a 5 year limited residential warranty which also covers the primary filter module but not the prefilter.  If the primary filter module should fail before the expiration of the warranty, a new filter will be supplied at pro-rata cost.  They are not warranted for commercial use.  However,  the PM-400 is covered under a commercial warranty.

• The HM-400 PLS, HM-400 STD, HEGA 2.1, and HM-200 are available in 3 colors.  The PM-400 is available in one color.

• The HM-400 PLS, HM-400 STD, HEGA 2.1, and PM-400 include high efficiency motors for conservation of electricity and lower electricity usage.  The HM-200 does not have a high efficiency motor.

• Casters - The HM-400 PLS, HM-400 STD, HEGA 2.1, and PM-400 include factory installed casters for roll-around convenience.

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