View Full Version : Air filters ..Hepa/carbon versus Ionizer

7th July 2009, 08:04 PM
We have a double use for an in room filter.

I need one room in our home office to be very dust free for opening LCD panels...

The other use is to see if it helps with allergies - so with the double use I'm not shy on spending a bit but can't decide between the two technologies.

Honeywell makes both

Permanent Filter Tower Air Purifier
Model: HHT-081C
Internet/Cat #: 936854
LifeTime permanent filter never needs replacing
Includes ionizer on/off feature for extra cleaning power and to help freshen the air
Easy to clean filter, simply use a vacuum
For medium sized rooms up to 169 square feet
Changes the air in the room up to every 12 minutes

Download Instructions

Clean the air in your home with the Permanent Filter Tower Air Purifier from Honeywell. Featuring a permanent filter that never needs replacing, this air purifier helps remove 99 percent of dust, pollen, tobacco smoke, cat dander and mold spores from the air in your home. When the electronic filter clean indicator lights up to tell you when its time to clean the filter, simply take it out, vacuum it, and place it back into the unit. With an ionizer to deliver extra cleaning power and help freshen the air, this air purifier runs quietly on any of its three air cleaning levels.

True HEPA Air Purifier with Germ Reduction
Model: 50250-N $299
Internet/Cat #: 936861
SurroundSeal technology helps minimize air leaks and insure that the air passes through the filter to capture particles
Operates at three different speeds: High, medium and low
Requires three HRF-14N replacement filters
Recommended room size: 374 square feet

Now the Hepa I know works well but filters need changing and I wonder if it's not overkill - they also tend to be noisier and more expensive.

The Ionizer we already have in the furnace but really need a specific cleaner for the dust free area

I'm thinking I will have to put some basic filter over the forced air vent to keep dust from the forced air system from intruding....

The Ionizer seems KISS.....

The Hepa and carbon are nice for odours and I know from my car the HEPA really helps with allergies....


Will the ionizer keep the clean room dust knocked down enough? :con2:

7th July 2009, 08:20 PM
I think the ionizers are mostly woo. They precipitate some stuff from the air, but my understanding is not as much as you'd hope, however a HEPA filter simply does not pass the stuff, which is why you need the filter changes.

7th July 2009, 08:26 PM
Ionizers make dust stick to surfaces, which takes the dust out of the air, but it means you'll have to dust more frequently.

The big issue with ionizers is that they produce ozone, which is bad for people with respiratory problems.

However, most air purifiers I've seen allow you to turn the ionizer off, so since that's the case with the model you're looking at, I'd go with the one with the lifetime filter.

7th July 2009, 08:32 PM
We use HEPA filters in our server (clean) room. FWIW.

7th July 2009, 09:11 PM
Carbon/activated charcoal is used to pick up odors and solvents. Like fumes and pesticides. I wouldn't think it would be the best filter for either fine dust or allergens. Ionization sounds like the way to go. But my experience was with wood dust collectors, and finish application/protection, not climate control.

What does HEPA stand for? I usually think charcoal when I see HEPA. but does it mean High Efficiency Purified Air, therefor not necessarily charcoal?

7th July 2009, 09:19 PM
A high efficiency particulate air or HEPA[1] (pronounced /ˈhɛpə/) filter is a type of high-efficiency air filter.

7th July 2009, 09:21 PM
High Efficiency Particulate Air. 0.3 micron of smaller pore size is the standard. 99.97% of all particles that size or larger are captured, and smaller particles at a reduced efficiency.

Robster, FCD
7th July 2009, 09:33 PM
If you are trying to keep those LCD interiors clean, then making particulates sticky may not be a good move.

8th July 2009, 01:24 AM
If you are trying to keep those LCD interiors clean, then making particulates sticky may not be a good move.

Y'know I think you have nailed it......:thumbsup:

Thanks for replies...HEPA it is....

8th July 2009, 03:36 AM
If you are trying to keep those LCD interiors clean, then making particulates sticky may not be a good move.

An ionizer makes particulates sticky. An electrostatic air cleaner catches them (large collectors are quite effective, moreso than the portables). Ionized particles usually travel no more than a couple feet with no fan and several feet downwind with one. I don't use just ionizers anymore because they leave a trail.:(

Dale H
8th July 2009, 05:02 AM
It has been a few years since I worked in the design of commercial clean rooms, but we used HEPA (high efficiency particulate arrestance) filters.

If you have air supplied to the room by your central air conditioning system, it will likely put airborne contaminents into the room faster than the portable HEPA unit can take them out, even if you do put a filter over the grille.

There are several levels of cleanliness, or classes, of clean room design and it is tough to tell just how clean you need to be. As a minimum, I would seal off the supply grille and vacuum the floor a few days before I wanted to work in the room and then let the HEPA thingy run to clean out the room. Then put a small portable fan near your work area. If the air is moving, it will tend to keep small particals air borne and prevent them from settling out on the equipment. And wear a hair net. Skin is on of the biggest sources of small airborne contaminants.

If you are really serious, you should create a "room within a room" of plastic sheeting.

Dale H

8th July 2009, 05:42 AM
Dale, I've actually seen a little pop-up dome tent with a HEPA vent fan for sale for portable and occasional use.

8th July 2009, 06:38 AM
I suggest you look to see what Consumer Reports has to say. That is, if they have tested them.

8th July 2009, 06:48 AM
Dale - good suggestions - I just bought a vacuum ( long overdue anyways ) with a Hepa filter and intended to dust and vacuum the room today - sealing the vent makes sense

It's not that critical as clean room - just needs to be reasonable....

8th July 2009, 07:07 AM

in a residence, the BATHROOM is usually the easiest place to get relatively dust-free.


8th July 2009, 10:13 AM
For our purposes the bathroom would have to be of royal dimensions