HVAC Filtration - Canadian TV, Computing and Home Theatre Forums
 5Likes
  • 1 Post By 57
  • 1 Post By ExDilbert
  • 1 Post By jasonreg
  • 2 Post By Jorgek
 
LinkBack Thread Tools Search this Thread Display Modes

post #1 of 10 (permalink) Old 2019-06-18, 08:40 AM Thread Starter
 
Join Date: Jan 2005
Posts: 283
HVAC Filtration

Hi, as a follow-on to a previous post, I am down to adding the "Accessories" to the new Furnace/AC purchase. I am curious as to the consensus on the various options for filtration:

1. MERV 11 (5" Filter - Dust/pollen/pet dander etc. down to 3 Microns)
2. MERV 16 (5" Filter with carbon layer - same down to 0.3 Microns) and
3. PureAir (Same MERV 16 + UV Lighting)

These would all be installed on the Air Returns prior ot entering the furnace. There is also the option of installing UV lighting on top of the AC Coils to prevent mold/bacteria growth there.

The major issue I have (cost aside) is the question of relative airflow through these filters. I have selected a very high efficient modulating Furnace/AC combo which should generally run at low speeds. Does this then minimize the benefits of the higher end filtration options. I should note that only one family member has what we would describe as moderate allergies.

Looking forward to hearing your thoughts. Jason
jasonreg is online now  
Sponsored Links
Advertisement
 
post #2 of 10 (permalink) Old 2019-06-18, 09:57 AM
57
Moderator
 
Join Date: May 2002
Location: Toronto, Rogers, 9865 & 8300-eHDD, Sharp LC75N8000U, Denon AVR4310Ci; Sony KDL40W3000, 9865
Posts: 56,068
There was a recent This Old House episode where UV was discussed. Basically, not required for most installations:

Here's a good article for your reference if you haven't seen it already:

https://www.thisoldhouse.com/ideas/r...r-conditioning

I assume that the filters you mention are "pleated" and not the electrostatic kind, which I installed. I clean my 5" electrostatic air filters in the dishwasher at the end of each "season", so twice a year. I believe the pressure drop of these is quite low. I'm not sure if the 5" pleated filters were available when I spec'd my furnace 30 years ago - perhaps only the 1" kind. I believe most people now recommend the 5" pleated. I spec'd these (electrostatics) because at the time we had two cats and my wife was allergic. We no longer have cats. There are plenty of articles on the web discussing the pros/cons of ESPs.

Again, good luck with your research.
Gentleman likes this.

57's Home Theatre (Latest equipment & photos)
57 is offline  
post #3 of 10 (permalink) Old 2019-06-18, 02:04 PM
Veteran
 
Join Date: Jun 2011
Location: 43° N, 81.2° W
Posts: 7,929
MERV 11 filtration is fine for most people. It's actually fairly good as a lot of filters are MERV8 or lower. The last 4" filters we purchased were MERV8. People who want "the best", have severe allergies or who live in highly polluted areas might want to go higher. Very small air pollution particles have recently been implicated in a number of common cancers. Unfortunately, they can't be avoided if you ever leave the home or open a window.

We have 4" filters which seems to be the most common size other than 1". Most retail stores charge $20 each but they can be purchased for much less. The wholesale price is about $6-$8. Advantages of the 4" filters is that they need to be changed less often and are more efficient than 1" filters.

Air filtration alone will not keep household air free of pollutants and allergens. Everything that may create or spread allergens and dust must be addressed. That includes things like carpets, rugs, furniture, pillows, blankets, clothing, towels, pets, mold, etc. Vacuum cleaners and other appliances the may circulate dust need to have HEPA filters.

Chemical pollutants created by household items such as cleaners, scents and perfumes will not be removed by filters. The scents put in many household products can potentially be as harmful and toxic as particle pollutants. Buy unscented cleaning products and be aware of potentially harmful chemicals they may contain.

There is some evidence that being raised in too clean an environment may lead to over-sensitivity to common allergens and other agents. It's probably wise to strike a balance with things like air filters unless there is a real need for special filtration.
Gentleman likes this.
ExDilbert is online now  
 
post #4 of 10 (permalink) Old 2019-06-18, 06:38 PM
 
Join Date: Mar 2006
Location: Port Stanley, ON
Posts: 540
The problem with high output UV light in air filtration is ozone production at low air volume levels.

I would think that on low fire in a modulating furnace, you could see ozone production with a UV light.

Delhi SFA 1483, Antennacraft Suburban VHF, CM7778
Gentleman is offline  
post #5 of 10 (permalink) Old 2019-06-19, 12:15 AM
57
Moderator
 
Join Date: May 2002
Location: Toronto, Rogers, 9865 & 8300-eHDD, Sharp LC75N8000U, Denon AVR4310Ci; Sony KDL40W3000, 9865
Posts: 56,068
Quote:
Originally Posted by Gentleman View Post
The problem with high output UV light in air filtration is ozone production at low air volume levels.

I would think that on low fire in a modulating furnace, you could see ozone production with a UV light.
The "UV Lighting" units in home furnaces typically don't generate ozone.

You may have been thinking about ESP (Electrostatic Precipitators) that I mentioned earlier. Although these can generate some ozone, they typically only do so when "zapping" large particles. Otherwise almost no ozone is generated by Electronic Air Filters or UV lighting. Certain ESPs are "better" for this than others. If interested in ESPs, do some research on the one(s) under consideration, but probably a large pleated filter will be adequate.

57's Home Theatre (Latest equipment & photos)
57 is offline  
post #6 of 10 (permalink) Old 2019-06-19, 09:24 AM Thread Starter
 
Join Date: Jan 2005
Posts: 283
Very helpful - thanks folks. I think I will forego the UV and go with the Merv 11 Filters.


Thanks again for all who chimed in. Jason

Oh, and 57 - that is a great article from This Old House. I had not seen it previously but that is great "one stop shop" for info. Thx.
Gentleman likes this.
jasonreg is online now  
post #7 of 10 (permalink) Old 2019-06-20, 08:42 AM
 
Join Date: Dec 2008
Location: Mississauga
Posts: 916
The video from This Old House is helpful. But the filter at the furnace is not the best you can see right through it. He should have replaced it with a more efficient pleated type. The better the filter the less dirt will build up on the evaporator.
Our furnace has the 5" pleated MERV 11 filter. The evaporator is squeaky clean and the fan is on year round.

OTA, CM4221HD, 3410 amp, 4 way split, HW-150 PVR.
FTA, Openbox S9, 33” dish, PLL LNBF. Stab 90HH.

Last edited by Jorgek; 2019-06-20 at 09:01 AM. Reason: update
Jorgek is offline  
post #8 of 10 (permalink) Old 2019-06-20, 10:37 AM
Veteran
 
Join Date: Jun 2011
Location: 43° N, 81.2° W
Posts: 7,929
Quote:
The better the filter the less dirt will build up on the evaporator.
I once lived in a house where the A/C evaporator was installed ahead of the filter. The A/C and heating started acting up after a few years. Some investigation revealed that the evaporator was coated with a solid layer of cat hair and dust. The reduced, almost blocked, airflow caused overheating and other problems.
ExDilbert is online now  
post #9 of 10 (permalink) Old 2019-06-20, 10:57 AM
 
Join Date: Dec 2008
Location: Mississauga
Posts: 916
My neighbor did major reno to his basement which included drywall all around. When summer arrived he complained about how poorly the AC was cooling the house. 2 HVAC technicians later revealed an evaporator caked with dry wall dust.
Gentleman and user_ like this.

OTA, CM4221HD, 3410 amp, 4 way split, HW-150 PVR.
FTA, Openbox S9, 33” dish, PLL LNBF. Stab 90HH.
Jorgek is offline  
post #10 of 10 (permalink) Old 2019-06-29, 02:58 PM
 
Join Date: Jun 2016
Posts: 77
the filter is there to keep the equipment clean and doesn't do much for air quality unless you run the fan continuously.

source control and ventilation do a better job of keeping air clean than a filter.

Running exhaust fans when showering/cooking is important.

If you have an hrv, use it but don't over-ventilate in the winter.

Avoid candles, get rid of carpets.

Avoid harsh chemical cleaners.

Use a central vacuum with the unit in a garage or vented outside.
user_ is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Canadian TV, Computing and Home Theatre Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome