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  1. #1
    Join Date
    Jul 2007
    Location
    Madison, WI
    Posts
    3

    Air to Air exhanger?

    I've got a 4 year old daughter with an asthma problem. We've discovered that if she gets a cold at a time of year when the house is shut up (using furnace or AC) it will trigger a violent cough that lasts for weeks and requires extensive medicating to control (and sometimes not even that will do it). However, if she gets ill when the house is open (mild weather) the cough doesn't occur. We've also had it happen when traveling to relatives' homes, so I don't think it's just our house. We have discovered that we can stop the cough by keeping windows open (even in below zero weather!).

    We're about to purchase a house that was built in the 1920's, and it has a 1950's era furnace. We're replacing the furnace (gas, forced air) adding AC, replacing all the windows for efficiency and quiet, and putting on a new roof. I'm concerned that this will seal the house even more and make the problem worse.

    Any advice about how to make sure fresh air is circulating? Any information about Air to Air Exchangers? We want to be as green and efficient as possible, but that seems antithetical to the Air to Air Exchangers. Thank you for any help you can provide.
    Jen

  2. #2
    Join Date
    Apr 2002
    Posts
    11,808
    the old houses were drafty, needed humidifiers, had a lot of natural air exchange

    Your rennovations sound like they will all reduce the natural air exchange.

    I would recommend something like a heat recovery ventilator. Brands like "Lifebreathe" "Venmar" "van EE"

    Get your total house volume -- total area (including basement) times ceiling height, gives you a volume in cubic feet.

    Multiply this volume by 0.005, will give you an airflow rate in CFM (cubic feet per minute) to give you about 0.3 air changes per hour. An HRV capable of this rate on high speed is what you should be looking at. They typically have multiple speeds, you could try lower speed constantly, kick it on to high speed when it gets too humid.
    The way we build has a greater impact on our comfort, energy consumption and IAQ than any HVAC system we install.

    http://www.ductstrap.com/

  3. #3
    Join Date
    May 2005
    Location
    Lubbock Texas
    Posts
    773
    You might want to read this article that was sent to me today from Canada.
    http://http://www.ctv.ca/servlet/Art...hub=TopStories
    You might be on to some thing with your observations with your daughter. Increased levels of carbon dioxide in the residence can lead to lower respiratory problems. It does sound like you need to have some type of forced air exchange rate in your residence. Don't know what part of the world you are in but I would also look at the humidity levels in the winter you might need to add humidity in the house too.

  4. #4
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,470
    The issues for indoor air quality are:
    1. Maintain <50%RH during the wet time of the year. Most important is the basement to avoid mold growth and and dust mites throughout the rest of the home.
    2. Have fresh air filtered air ventilaiton when the home is occupied. 50-75 cfm of air is enough for purging pollutants and renewing oxygen.

    There is equipment that will provide this. The ventilating dehumidifier like Ultra-Aire/Santa Fe/Honeywell are high eff. units that work with a/c. Check out thermastor.com, a Madison mfgr., is local (I am employee). Check the "teddy bear" post for info on IAQ. TB

  5. #5
    Join Date
    Jul 2007
    Location
    Madison, WI
    Posts
    3

    Thanks

    We live in Wisconsin, where the winters are dry and cold, and the summers are hot and humid. Thanks so much for all your suggestions. We have a furnace with a humidifier now, and if I had the choice, I'd probably try radiant heat. But since we don't, I'm just looking for the best we can do. Sleeping with open windows in Wisconsin winters is harsh! Teddy Bear, I'm so excited you're in Madison. I hope we'll do business.
    Jen

    ps. Genesis, I was unable to open the link. I'll search ctv for an article on carbon dioxide....

  6. #6
    Interesting. I am not sure I have heard of a situation quite like it. Your child has a prolonged cough if the windows are not open. Usually, it is the other way around.

    Here are some thoughts:
    1. Humidity may be the answer to the problem. You need to buy a humidistat and keep humidity below 50% but not less than 30% in the winter. Oftentimes the humidity gets pretty low in houses in cold climates during the winter. The dry air can cause coughing. Pediatricians swear by a good humidifier.

    2. Have your child allergy tested. Four is about the age where testing makes sense. If you know the allergens driving the inflammation part of the asthma, you can make some good decisions about what to do.

    3. I like the idea of a ventilating dehumidifier. adequate quantities of fresh air to bring in oxygen and dilute pollutants can't hurt. Make sure the fresh air is properly filtered.

  7. #7
    Join Date
    Apr 2002
    Posts
    11,808
    50 to 75 CFM may or not may be enough fresh air. Depends on size of the house, what the exact ailment is.
    The way we build has a greater impact on our comfort, energy consumption and IAQ than any HVAC system we install.

    http://www.ductstrap.com/

  8. #8
    Join Date
    Jul 2007
    Location
    Madison, WI
    Posts
    3
    We have had our daughter allergy tested twice, and her only allergy is to ragweed, and even that is mild. We've been dealing with pediatric allergy and asthma specialists at the University of Wisconsin Hospital for three years now. We've tried dairy and wheat-free diets, herbs, tons of medicines, we've put a HEPA air filter in her room, we've encased all her bedding in dust-mite proof sheeting, etc.

    What clued us in that it's something inside the house is that in the winter any illness she gets triggers this, but in the summer illness doesn't trigger it... until one week when it was really hot AND she was just recovering from a cold. We had the AC on for a few days at this point, and for the first time she got the cough in the summer.

    She's visited relatives' homes over the course of a week or so in the winter, and had the cough, so I'm sure it's not just our home. But the drive to the emergency room in the middle of the night in winter always calmed the cough! By the time we got to the hospital, her cough would always calm down. In fact, one night I refused to take her back home (it was our second trip to the ER that night). I saw that once she got home the cough came back, so I commandeered a hospital room and told them we were sleeping there for the rest of the night. And she slept. (no, hospital staff were not happy with me.)

    Thanks all for your suggestions... my ears are open!
    Jen

  9. #9
    Join Date
    Apr 2002
    Posts
    11,808
    Quote Originally Posted by genesis View Post
    You might want to read this article that was sent to me today from Canada.
    http://http://www.ctv.ca/servlet/Art...hub=TopStories
    You might be on to some thing with your observations with your daughter. Increased levels of carbon dioxide in the residence can lead to lower respiratory problems. It does sound like you need to have some type of forced air exchange rate in your residence. Don't know what part of the world you are in but I would also look at the humidity levels in the winter you might need to add humidity in the house too.

    Could never find that link gen, but searching CTV, the most recent link was about a bunch of Inuits (PC for Eskimoes)getting sick. It mentioned that it was typically more people in the household than the typical Canadian family like 6 instead of four, and the places were ventilated at 80&#37; of the code required rates for the rest of Canada.

    Homes were probably sealed pretty tight considering the location.

    In Canada you have to have a system in place that can give the 0.3 ACH when needed. Another methodology is also based on rooms. 10 CFM a room, 20 CFM for master bed, 20 CFM for an unfinished basement. Usually works out to roughly 0.3 ACH.

    I wonder what the magic number is for CO2?
    The way we build has a greater impact on our comfort, energy consumption and IAQ than any HVAC system we install.

    http://www.ductstrap.com/

  10. #10
    Join Date
    May 2005
    Location
    Lubbock Texas
    Posts
    773
    Carnak ASHRAE likes to see it less than 1000ppm. But in all the commercial buildings we have controlled the fresh air with ddc controls we go ahead and start modulating the fresh air dampers open at 800 ppm and close them off or to around 10% or less at 700ppm. I have noticed in all the casinos we do the magic number when the customers start complaining about air quality is around 1300 ppm.
    I must not have posted the whole article eddy when I pasted it but it was based in Canada and a case study from a hospital about asthma attacks and sinusitis and pnemnonia being triggered from high levels of CO2 in the home either from lack of air changes or over crowding in the home.

  11. #11
    It has been awhile since I have worked with this but I seem to remember that over 800 ppm of CO2 was a problem that needed to be corrected. I am not aware of this level be exceeded in a house unless there is something wrong with the HVAC system or some other combustion device in the home.

    JenH, it sounds like you are well ahead of the curve in terms of dealing with your child's asthma. Unfortunately asthma can be baffling, frightening and frustrating. The good news is that most children have improved symptoms as they get older and the disease is controllable in most cases. I am sure the Docs at U of W are prescribing the correct medications to control inflammation and give quick relief if necessary. Just keep up with her prescriptions and compliance.

    One thing that intrigues me is why your daughters symptoms would be better in the hospital. Obviously, this is conditioned air as well. My experience is that most children with asthma get better in the hospital but that is because of the smooth floors, encased mattresses and pillows and controlled humidity.

    Making your home as close to hospital conditions as possible (or at least the part your child is exposed to the most) would seem like a wise course to take.

  12. #12
    Genesis
    I would like to read the article if you can find it. I was not responding to your post. I just happened to be composing mine when you sent in yours.

    I would like to know more about higher CO2 levels in homes.

  13. #13
    Join Date
    May 2005
    Location
    Lubbock Texas
    Posts
    773
    Jim go to http://www.ctv.ca/

    Then put indoor air quality into the search box. It should be the top selection.
    http://www.ctv.ca/servlet/ArticleNew...0716/20070717/
    Last edited by genesis; 07-22-2007 at 11:03 PM.

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