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Thread: At what point would you pull the trigger on improving air quality?

  1. #1
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    At what point would you pull the trigger on improving air quality?

    Preface: Shout out to those of you who contribute to HVAC-TALK. I've leaned on your insight for years, and deeply appreciate it. Thanks for making the internet go around.

    Info:
    Home 2700 sq. foot near Austin, TX, two story, AC 4 tons downstairs, 1.5 tons upstairs. Seer 13 system going on 20 years old.
    Family: 6 of us (4 children 10->16), some of us suffering asthma, headaches, fatigue. 3 of us have difficulty sleeping. Indoors have 4 cats and 1 dog. We run HEPA filters in bedrooms where we have sufferers. I still have to wear a breath-rite strip to sleep every night due to chronic rhinitis (have had this since moving to Austin 25 years ago though).

    We recently began testing our indoor air quality, and found CO2 at 700-800ppm ABOVE background consistently in occupied spaces (i.e. 1100-1400 ppm is typical). VOCs at about 400 ppb higher than outdoors.


    Here's our dilemma: We have no idea whether spending thousands of dollars would leave us in a better position than we are now. I'm fighting my better angels here; my optimism wants to believe that improving IAQ would alleviate the symptoms we think we have, and make life magical again.

    Research here and elsewhere has led me to believe that something like an Ultra-Aire 120H pulling air 24/7 through the MERV 14 upgrade would help, although I'm concerned that all it might do is tax an already aging AC system.

    Is there anyone who might be able to make a case one way or the other so I can stop obsessing over this? We asked for quotes from 5 contractors... 3 didn't reply, one can't help, one suggested $4-$5K to install an Ultra-Aire 98H.

    Best Regards,
    Thomas.

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  3. #2
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    Quote Originally Posted by tzm View Post
    Preface: Shout out to those of you who contribute to HVAC-TALK. I've leaned on your insight for years, and deeply appreciate it. Thanks for making the internet go around.

    Info:
    Home 2700 sq. foot near Austin, TX, two story, AC 4 tons downstairs, 1.5 tons upstairs. Seer 13 system going on 20 years old.
    Family: 6 of us (4 children 10->16), some of us suffering asthma, headaches, fatigue. 3 of us have difficulty sleeping. Indoors have 4 cats and 1 dog. We run HEPA filters in bedrooms where we have sufferers. I still have to wear a breath-rite strip to sleep every night due to chronic rhinitis (have had this since moving to Austin 25 years ago though).

    We recently began testing our indoor air quality, and found CO2 at 700-800ppm ABOVE background consistently in occupied spaces (i.e. 1100-1400 ppm is typical). VOCs at about 400 ppb higher than outdoors.


    Here's our dilemma: We have no idea whether spending thousands of dollars would leave us in a better position than we are now. I'm fighting my better angels here; my optimism wants to believe that improving IAQ would alleviate the symptoms we think we have, and make life magical again.

    Research here and elsewhere has led me to believe that something like an Ultra-Aire 120H pulling air 24/7 through the MERV 14 upgrade would help, although I'm concerned that all it might do is tax an already aging AC system.

    Is there anyone who might be able to make a case one way or the other so I can stop obsessing over this? We asked for quotes from 5 contractors... 3 didn't reply, one can't help, one suggested $4-$5K to install an Ultra-Aire 98H.

    Best Regards,
    Thomas.
    Id do it now. If I were your Id think about getting a new unit and get the install done correctly where the unit will accept method 13 filters and not be starved for air. And then get a separate ERV installed. I have even higher CO2 levels than you.. I dont have those issues but when Im home I feel a little... foggy. More then a few studies have found that high CO2 levels decreases cognitive ability by 60-100%


    Sent from my iPhone using Tapatalk

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  5. #3
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    Quote Originally Posted by Tekjunkie View Post
    Id do it now. If I were your Id think about getting a new unit and get the install done correctly where the unit will accept method 13 filters and not be starved for air. And then get a separate ERV installed. I have even higher CO2 levels than you.. I dont have those issues but when Im home I feel a little... foggy. More then a few studies have found that high CO2 levels decreases cognitive ability by 60-100%


    Sent from my iPhone using Tapatalk
    So your thought is that the MERV 14 option will restrict intake too much?

    I guess the ERV suggestion implies that given our (often) 100+ degree temps, the humidifier is going to intake too much heat to handle via the existing AC?
    If we were going to get an ERV anyway, I would imagine that the humidifier wouldn't need a fresh air intake... just let the ERV handle that part and focus the dehumidifier on drying the house air?

    Is an ERV even necessary over an HRV, if you're installing a dehumidifier anyway?

  6. #4
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    Before you make a commitment, test for mold spores also. Kits are available at Lowes ( https://www.lowes.com/pl/Mold-test-k...ies/4294518335 ) and other sources. That is more likely to cause issues than your co2 levels. Would also test for allergies to animals. Check indoor humidity levels, best ~45% for mold control, 55% for bacteria and virus control.
    The mold test kits give an indication of mold quantity and sending to a lab will identify the types of mold, some toxic, some not.

    One such health concern is mycotoxicosis — mold poisoning. Others include:
    aches and pains
    changes in mood
    headaches
    memory loss
    nosebleeds
    Stachybotrys mold has been the subject of a number of law suits. Permanent brain damage and some symptoms similar to alzheimer's are claimed

    Common issues contributing to mold:
    oversized short cycling equipment
    improperly installed or maintained equipment with inadequate latent capacity
    panned returns
    leaky ducts
    improperly vented bathroom exhaust, kitchen exhaust, dryer exhaust systems
    wet craw spaces
    concealed water or drain leaks

    Good luck!

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  8. #5
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    This is a real can of worms. Expensive and no promises. I have been in some thorny ones.
    In most of cases, most feel that they have improved their health and comfort by getting steady filtered air change and avoiding extended damp days. Comfort always improves. Also there may be damp spot someplace in the indoor space that causes most of serious problems. You may miss it in all of your fixes.

    Main issues:
    Damp crawlspaces, all spaces should be <60%RH for extended hours. Carpet/concrete interfaces are toughest. Mold and mites like these spaces. The cool concrete raises the %RH to +60% from the moisture in the home.
    A/c damp spots like the drain pan or dampened material down stream of the cooling coil. Continuous circulation of dry air throughout the ducts to avoid damp spots for +24 hours avoid mold. Mold testing is problematic because of occasional damp days may not occur at the time of testing. Also maintain <50%rH throughout the seasons of the year. A/c is unable to keep all this material dry during evenings and rainy weather.
    Dust mites are the most common allergen according the Am Medical Assn. They live anywhere skin scales accumulate and the humidiy is +60%RH for a couple months a year. Bedding/carpeting/cloth chairs are favorite spots. Maintain <50%RH throughout the year is a sure fix for this.

    Accumulation of indoor pollutants is vague. Most suggest that a fresh air change in 3-5 hours will purge indoor pollutants and renew oxygen to optimize indoor space conditions to avoid these problems. CO2 itself is not a problem but rather an indication of fresh air when the home is occupied.
    In your home, monitor your CO2 levels during occupancy. During mild summer temperatures and calm winds conditions are the times of low air change. Windows are closed and the home is occupied. One person in your home with 650 ppm of CO2 indicates 50 cfm of fresh air change. Your home needs a minimum a 100 cfm with one or 8 occupants. 100 cfm of filtered, merv13, 24/7 would be a start.
    This fixes the common things that I can think of right now.

    An Ultra-Aire 120 with 100 cfm 24/7 make-up set at <50%RH is the change I would suggest. Your a/cs setup should be checked for ideal draining on pans and confirm air flow optimize moisture removal by the a/cs.
    Then the adventure starts. It takes a year for the dust mites to die and their allergen to breakdown. Mold general goes away quickly.
    The quote you got is common for most good contractors. It would be less if he did it everyday. Probably the contractor is plenty nervous about the whole deal.
    Some of the national home builders are including these system in every deluxe home they build in humid climates.
    That is my short version about the solution.
    Keep us posted.
    Regards Teddy Bear
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

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  10. #6
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    Quote Originally Posted by tzm View Post
    So your thought is that the MERV 14 option will restrict intake too much?

    I guess the ERV suggestion implies that given our (often) 100+ degree temps, the humidifier is going to intake too much heat to handle via the existing AC?
    If we were going to get an ERV anyway, I would imagine that the humidifier wouldn't need a fresh air intake... just let the ERV handle that part and focus the dehumidifier on drying the house air?

    Is an ERV even necessary over an HRV, if you're installing a dehumidifier anyway?
    No I recommend a ERV with merv 14 separate from the HVAC. But in reference to the HVAC system make sure they make your filter holders large enough to accommodate 4 thick merv 13 or so filters without restricting airflow (static pressure).

    I also do NOT like a dehu with fresh air intake unless it can be filtered. But then again the Dehu isnt as efficient as an ERV. But maybe you will need a whole home dehu and a ERV.

    Also test for mold and chemicals, since your CO2 levels are that hi go ahead and plan for anERV. In the mean time run the bathroom exhaust fans and report back here of any changes in health. Thats very concerning, we want everyone to be healthy.


    Sent from my iPhone using Tapatalk

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  12. #7
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    Thanks Teddy.

    Would the MERV 14 upgrade be worth anything over the stock 13?

    We have a 20x25x5 filter housing in the 1st floor HVAC return that has a MERV 13 in it as well, so maybe that's overkill. Would like to keep the winter Cedar Pollen out if we can.

  13. #8
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    Quote Originally Posted by tzm View Post
    Thanks Teddy.

    Would the MERV 14 upgrade be worth anything over the stock 13?

    We have a 20x25x5 filter housing in the 1st floor HVAC return that has a MERV 13 in it as well, so maybe that's overkill. Would like to keep the winter Cedar Pollen out if we can.
    No, Air filtering beyond mold spores, pollen, and dust is tricky. The next step would HEPPA and activated Carbon. This would only be recommended for extreme sensitivity or local conditions in the area of the home.
    Our merv 14 was developed several years before we merv 13 in our dehumidifiers.

    A fresh air change in 4 hours with merv 13 and maintaining <50%RH should make an adequate change to bring relief to most.
    Also avoid over-cooling below the outdoor dew points to minimize the amount of condensation in the structure and on the a/c equipment. This a fine line to get the a/c equipment to remove adequate moisture during peak sensible and latent cooling. Your dehumidifier is mainly for evenings and rainy days.

    Keep us posted with another questions.

    Regards Teddy Bear
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  14. #9
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    Do not expect a single device to solve IAQ problems.

    I suggest you have a blower door test and duct leakage test to begin with. You need to focus on keeping the air in the house actually in the house. Infiltration and duct leaks will negate filtration and fresh air. Start by tightening the house and then reassess. If you get the house tight enough then an ERV may be a good idea, but old houses are hard to seal to that extent.

    I do like the Aprilaire Merv 13 low pressure drop air filter (or higher it the static pressure drop is acceptable) and I also like a ducted dehumidifier as Teddy Bear recommends for low load conditions.
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  15. #10
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    Thought following up on Teddy Bear's thoughts..

    Bringing in fresh air... at the return side of a ducted system... will slightly pressurize the house...
    The result of doing this... will decrease infiltration and increase exfiltration...
    Thus you are in control of what air comes into the house.

    Thought: Give some consideration to WHERE the intake duct for fresh air (outside air) is placed. Obviously... one does not want to suck that air from a low point, behind a bush, where water puddles all the time...
    Rather... from a place away from any and all vents (vents like exhaust from a furnace, water heater, dryer, kitchen vent hood, bath vent hood, etc...)

    And I agree... 3-4 air changes per 24 hours is a good idea!!!
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *The value of comfort, over the long term; leave economic choices behind!
    Choose your contractor wisely!

  16. #11
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    Quote Originally Posted by tzm View Post

    Info: VOCs at about 400 ppb higher than outdoors.
    Curious how you determined your VOC levels. If you used one of the consumer MOS based meters that are readily available I'd be very hesitant in believing the results.

    I'd recommend doing a Gas Chromatorgraphy/Mass Spec test.
    Home Air Check (Prism Labs) will supply a calibrated suction device to sample a metered quantity of air for a fairly accurate analysis for both TVOCs and content.
    For more detailed results results seek out the services of Dr. Randal Fike.

    Even moderately raised CO2/VOC levels can put a damper on cognitive parameters..
    For a real eye opener check at this overview of a study by these Harvard researchers:

    https://hbr.org/2017/03/research-sta...ess-productive

  17. #12
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    I'm late to this discussion, but let me provide my 2 cents. To improve your air quality think about: 1) source control 2) ventilation 3) air cleaning.

    1) Source control: Are there chemicals you can remove from the home? Are there damp spots you can fix? Is your vacuum just stirring up dust? Are there pests in the home?

    2) Ventilation: An ERV and ventilating dehumidifier (like the Ultra-Aire you mentioned) are both options to explore. They address the humidity issue which happens when bringing in outdoor air.

    3) Air cleaning: If you are running portable HEPA filters in the rooms with allergy sufferers, you're not going to get any better filtration through the HVAC system, so don't even try.

    In general, people over-promise the health benefits you'll get with any one strategy. Keep making improvements in the 3 categories above and report back how it all worked.

  18. #13
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    Regarding air quality testing... sometimes these can help (VOC testing, mold testing, airborne allergen testing), but they don't always pinpoint the problem. Just like people over-promise the benefits of IAQ equipment, people often over-promise air quality testing.

  19. #14
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    Fortunately, it is possible to monitor and improve indoor air quality, starting with the most frequently used rooms. Have IAQ specialist check air pollution in your home, office or other public spaces. I recently hire XXXXXX for Air quality Testing. If your symptoms are not evident, it is reasonable to try to improve indoor air quality. Thus, hire the professional Air Quality Testing services company as soon as possible to get the best services.
    Last edited by Dad; 11-09-2020 at 10:08 AM.

  20. #15
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    Quote Originally Posted by Devin Williams View Post
    Fortunately, it is possible to monitor and improve indoor air quality, starting with the most frequently used rooms. Have IAQ specialist check air pollution in your home, office or other public spaces. I recently hire XXXXXX for Air quality Testing. If your symptoms are not evident, it is reasonable to try to improve indoor air quality. Thus, hire the professional Air Quality Testing services company as soon as possible to get the best services.
    Please try not to mention names of companies you may do your professional business with. We have a strict advertising rule until you become a Pro member here.



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