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  1. #53
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    Great thread! I will, hopefully soon, be getting a CO2 monitor to measure my house. I have an ERV with a percent timer. I bet I am over ventilating a lot of the time.

  2. #54
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    Quote Originally Posted by chuckcrj View Post
    Great thread! I will, hopefully soon, be getting a CO2 monitor to measure my house. I have an ERV with a percent timer. I bet I am over ventilating a lot of the time.
    Keep us posted. My guess is that you are over-ventilating during cold windy weather, about right during moderate weather, and under ventilating during warm calm. What part of the country are you in? How is your indoor dew point verses outside dew point or indoor %RH? How many occupants and sqft. of home?
    Keep us posted.
    Regards TB
    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"

  3. #55
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    Jun 2009
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    Albuquerque NM
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    I read an article somewhere that said they checked a bunch of homes and found that 77% were overventilated.

    From what I've read so far. I think that without using some measure like CO2, the only way to insure enough ventilation is to overventilate part of the time. Seems kinda whacky to me, but that's what it appears.

  4. #56
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    Quote Originally Posted by teddy bear View Post
    Keep us posted. My guess is that you are over-ventilating during cold windy weather, about right during moderate weather, and under ventilating during warm calm. What part of the country are you in? How is your indoor dew point verses outside dew point or indoor %RH? How many occupants and sqft. of home?
    Keep us posted.
    Regards TB
    NW Wisconsin.
    2800 sq ft including conditioned basement.
    Mom, dad, a 2 year old and 4 year old.

  5. #57
    Join Date
    Jul 2008
    Location
    Rochester NY
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    Quote Originally Posted by chuckcrj View Post
    Great thread! I will, hopefully soon, be getting a CO2 monitor to measure my house. I have an ERV with a percent timer. I bet I am over ventilating a lot of the time.
    +1, really really good stuff.

    Maybe I'll get me a co2 logger and stop running my erv continuous.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  6. #58
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    Jun 2003
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    Quote Originally Posted by tedkidd View Post
    +1, really really good stuff.

    Maybe I'll get me a co2 logger and stop running my erv continuous.
    From what I am finding, you will save energy, moisture, and wear by not operating your erv when not occupied throughout the year. Also operating full time when occupied and calm winds/moderate temps provides better indoor air quality. The % timers under ventilate when you need the ventilation. You over-ventilate when unoccoupied and windy, cold weather. Better moisture conservation during extreme low outdoor dew points is the biggest benefit. 3-4 occupants are needed to keep a small home at comfortable moisture levels during low winter outdoor dew points. CO2 ventilation control does have benefit for automating the on/off control of any ventilation device. Most occupants will not deal with the daily adjustment needs for ideal ventilation schedules.
    Regards TB
    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"

  7. #59
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,728
    Keep repeating it. All those concepts are sinking in, making ever more sense.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  8. #60
    Join Date
    Jun 2009
    Location
    Albuquerque NM
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    Getting back to my idea about "base ventilation". This is used in commercial buildings where there are non-occupant sources of CO2 that prevent the indoor CO2 level from returning to outside levels (~400PPM). In other words, the building always needs that much ventilation to return to "fresh air" CO2 levels even when not occupied. This allows sensors that use ABC (automatic background calibration) such as the Honeywell C7232A to calibrate properly. Using ABC, the sensor never needs manual calibration for the life of the sensor (~15 years).

    OK, so that's for commercial, but we're talking about residential so why am I bring this up? Sensor ABC algorithms need the indoor CO2 to drop to outdoor levels at least once every 7 or 14 days, depending on the sensor. Checking my indoor CO2 levels, I see that when the house is unoccupied for a few hours, I never get to 400PPM. It does get to 600 or 700 occasionally, either when we're out for a few hours or when we're sleeping, or when it's really windy. So, I was thinking, why not use base ventilation to bring in a small amount of ventilation continually, to get the base level down closer to that of outdoor levels. In commercial, I have seen numbers like 20% or 25%.

    So how would we do that in a home. What about controlling ventilation with a timer to provide 20-25% of the ASHRAE requirement, in parallel with a CO2 sensor that would fully open the vent? So, in other words, the house always gets 20% to 25%, but gets full ventilation if the sensor reaches the threshold (800, 1000, or 1200).

    Any thoughts or ideas?

    Here's an interesting paper on the subject. Though written for commercial, some of it still applies.
    https://www.airtest.com/support/reference/paper1.pdf

  9. #61
    Join Date
    Jul 2008
    Location
    Rochester NY
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    Panasonic has bath fans that ramp up and down based upon motion sensing. Put one in my GF's house, set continuous at 30, jumps to 80 or 100 when it senses.

    My ERV has all kinds of settings, and a 15 minute high button in the bathroom. (She's not thrilled when I see the master control showing "high fan" and I shout "are you pooping?"
    She keeps a copy of Dale Carnegie on my bed-table, and I can almost hear her thinking "read the book a-hole!") :-)

    I suspect what you want is out there.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  10. #62
    Join Date
    Feb 2010
    Location
    In a boiler room
    Posts
    7,118
    Teddy Bear,

    Do you have a link to the product from Ultra Air that you talked about that controls ventilation by CO2 levels?

  11. #63
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
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    6,432
    Quote Originally Posted by chuckcrj View Post
    Teddy Bear,

    Do you have a link to the product from Ultra Air that you talked about that controls ventilation by CO2 levels?
    This is a custum control without support currently. Will become a fully supported control in a few months. From what I am seeing, If the space never gets below 600 ppm CO2, the control will read 450 when it is really 600. You set the control to activate at 600, this provides fresh air when occupied.
    In addition, when you have active ventilation, the space may will be at 600 when you leave the space. Thus the space will go lower and readjust the sensors reading.
    Also the ABC number and time is programable. This means you can determine the time and ppm. Currently we are using 450 and 2 weeks.
    I have access to a limited number of custom DEH 3000 controllers with CO2 control of fresh air ventilation. I have some operating for upto 18 months of operation. Refinements a being made as we speak. I am using them on different types of ventilation systems like ERV, make-up, and exhaust systems.
    Regards TB
    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"

  12. #64
    Join Date
    Jun 2009
    Location
    Albuquerque NM
    Posts
    2,485
    Quote Originally Posted by teddy bear View Post
    This is a custum control without support currently. Will become a fully supported control in a few months. From what I am seeing, If the space never gets below 600 ppm CO2, the control will read 450 when it is really 600. You set the control to activate at 600, this provides fresh air when occupied.
    In addition, when you have active ventilation, the space may will be at 600 when you leave the space. Thus the space will go lower and readjust the sensors reading.
    Also the ABC number and time is programable. This means you can determine the time and ppm. Currently we are using 450 and 2 weeks.
    I have access to a limited number of custom DEH 3000 controllers with CO2 control of fresh air ventilation. I have some operating for upto 18 months of operation. Refinements a being made as we speak. I am using them on different types of ventilation systems like ERV, make-up, and exhaust systems.
    Regards TB
    I think this will be a popular product. With the cost of CO2 sensors dropping, emphasis on energy conservation, and increased awareness of IAQ, having an integrated product should be a good thing.

    Of course, it appears that you can combine a CO2 sensor with any type of ventilator and maybe accomplish "almost" the same thing.

    Oh, and if one of the high-end thermostat manufacturers would add CO2 sensor input to one of their thermostats, well that would be excellent too.

  13. #65
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
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    Quote Originally Posted by garya505 View Post
    I think this will be a popular product. With the cost of CO2 sensors dropping, emphasis on energy conservation, and increased awareness of IAQ, having an integrated product should be a good thing.

    Of course, it appears that you can combine a CO2 sensor with any type of ventilator and maybe accomplish "almost" the same thing.

    Oh, and if one of the high-end thermostat manufacturers would add CO2 sensor input to one of their thermostats, well that would be excellent too.
    Here is an interesting point. The weather data for last year shows that you have high winds abount once per month. I am attaching the data. It show 20-30 mph winds occasionally. This level of wind will reduce the CO2 levels in a home signicantly. This is an opportunity to reset the meter more accurately. Between varible weather and opening the home, ABC calibration should be adequate. Also I found a plastic garbage bag of fresh air around the meter resets the ABC.
    Regards TB
    This is from wunderground.com
    History for Albuquerque NM.pdf
    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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