Pollen filtration for forced air system


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Old 02-28-23, 06:50 AM
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Pollen filtration for forced air system

I’ve read here about not using high MERV filters as they shorten the life of blowers. Also that furnace filters are designed for protecting blowers, not for air purification. Is there something that can be added to the HVAC system that effectively filters pollen out of the home?
 
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Old 02-28-23, 07:31 AM
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You could look at adding an electrostatic air cleaner, such as those made by honeywell and aprilaire to your furnace. They can be very effective at removing pollen. Most also incorporate a media filter after the electrostatic stage, so the unit has to be chosen to be compatible with the air flow rate of your furnace or air handler, and the size has to be compatible with your return air ducting.

This type of filter does emit a small of ozone into the air stream. The level is low, but some people are sensitive to it.
 
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Old 02-28-23, 07:35 AM
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You can also use separate air filters. They can work even when your cental HVAC system is off. Especially important during the spring when you don't need heat or AC and the pollen is turning your car yellow.
 
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Old 02-28-23, 09:01 AM
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The last 4 homes we built we installed different types of filters, conventional disposable, electrostatic, and the large cartridge type. We had never found one that gave us that AH-HA moment!

When you think about it, the furnace, either heating or cooling, runs just a short time, something in mild weather not at all. A filter does nothing without air flow.

Not saying it's a waste but I personally would not spend the money on anything but just mildly efficient disposable filters!
 
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Old 02-28-23, 10:05 AM
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“The last 4 homes we built we installed different types of filters, conventional disposable, electrostatic, and the large cartridge type. We had never found one that gave us that AH-HA moment!

When you think about it, the furnace, either heating or cooling, runs just a short time, something in mild weather not at all. A filter does nothing without air flow.

Not saying it's a waste but I personally would not spend the money on anything but just mildly efficient disposable filters!” Marq1

Marq1 has voiced my concerns rather well. Also, not a fan of free standing self contained ones either. I do understand the free standing ones can run 24/7 and not negatively impact the HVAC system. Just wonder how effective they are for an entire home. Hate to think I need several, one for each room. Surely the serious allergy sufferers have found something that is effective.
 
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Old 02-28-23, 10:49 AM
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With an electrostatic (or any filter really) you can set your furnace to run the fan 24/7. With old single speed furnaces this can be expensive and noisy, but with newer equipment with multispeed blowers you can run it on low 24/7 and get the advantage of whole house filtration without much noise or expense. We run our furnace fan on medium low 24/7 and have really noticed the difference in reduced need for dusting. It also helps with evening out temperature variations throughout the house.
 
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Old 03-15-23, 03:25 PM
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Hi, I have a hard time figuring out how the filter does not filter the air , any air going through the return must go through the filter, how can it not be cleaner?
Geo 🇺🇸
 
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Old 03-15-23, 04:07 PM
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Sure, it's cleaner, but filters only filter particles as large or larger than the holes in the filter. Smaller stuff gets through no matter how many times the air is circulated. If you put in a better filter (smaller holes, essentially) it can also reduce the air flow enough to harm your furnace, either by causing the blower to work too hard, or by overheating the heat exchanger because not enough air is moving past it fast enough.
Some pollen, things like viruses, smoke particles, all these things can get through a lot of the filters being sold.
 
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Old 03-15-23, 04:13 PM
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Pollen can be smaller than dust and go right thru most filters.
 
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Old 03-15-23, 05:28 PM
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I feel like I notice a difference with my electrostatic filter.

gotta leave the thermostat on on instead of auto or it’s not going to do anything though.
 
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Old 03-16-23, 06:47 AM
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I’ve read the electrostatic ones work great, when they are clean. And, they need to be cleaned frequently. My air exchanger is in the attic, accessed by folding stairs. Otherwise that would have been my choice.

I have ruled out HVAC filtration for allergens. Now I am working with an ENT and allergist. If they can reasonably fix me then I won’t have to make the house a clean room and be held hostage during allergy season. Makes the most sense.

Thanks for the advice and feedback.
 
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Old 03-18-23, 04:19 AM
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Electrostatic filters can be very restrictive and are not a good option because they reduce airflow with PSC motors and cause high amperage with ECM motors.


Electronic air cleaners don't restrict the air very much at all. ( ~ .11"W.C.)
They cost a lot more since they must be installed into the ducting by an HVAC contractor. Cleaning them can be a chore if you don't have a maintenance agreement with a contractor to service the HVAC equipment and wash the filters for you.


 
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Old 03-18-23, 07:42 AM
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Ok, I’ll confess to thinking electronic air cleaners and electrostatic filters were the same. Electronic air cleaners are what I was thinking of. So, are you saying these electronic devices can only need cleaning once or twice a year? Or, even less often, and still do a good job off removing allergens?
 
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Old 03-18-23, 08:38 AM
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I wash them 4 times a year for my customers and they work great.
Twice a year tends to get them very dirty.


Our Honeywell rep spoke of popping them in the dishwasher but I have never tried that option.
 
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Old 03-18-23, 02:06 PM
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I always thought they were the same as well. Wikipedia calls them “electrostatic precipitators”

I just soak my cells in a bath tub with a bit of dishwasher detergent per the manufacturers recommendation every other month or so. It’s a little tedious but not too terrible. Just have to be careful about breaking the ionizing wires which are mysteriously expensive
 
 

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