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  1. #40
    Quote Originally Posted by tedkidd View Post
    Each situation is different and basing design decisions solely on rules of thumb often get clumsy results, as the decision to get an hrv instead of erv may have done in this situation.

    WEATHERMANKS, where is the moisture coming from? From the ground, occupants, something else? That's where you need to start.

    AUDITOR, sounds like you might want to swap cores with WEATHERMANKS as It sounds like your HRV and his erv assumptions were wrong. As BEENTHERE implied your house is not as tight as super efficient houses that require DEHUMIDIFICATION in winter. Sounds like you need to recover latent rather than expelling it.

    Furthermore, have you tested your IAQ or are you basing your fresh air requirements on rules of thumb as well? Ive been in leaky houses with crap iaq and tight houses that were fine. Standards are just starting points, not guarantees.

    You may also want to check your Evo settings. Set only to humidify when heating? You may never get enough humidification with that setting particularly if the furnace is oversized. Ditto if you have a flow through humidifier running cold water. Did you get a water saver or one of those water wasters?

    Finally, depending on your hrv integration you may not need to run it at all. Is it piped to your furnace return? Running the furnace fan will run air in and out due to the pressure imbalance. Do you run the evo fan full time?

    Cycling equipment will shorten it's life. I run my erv on constant.
    TEDKIDD

    Thanks for your response but it seems you missed my main point, which is when using the Infinity control with the ventilator attached via a NIC, you do NOT have proper control of the ventilation. I have tested this system in other houses also and the controls do not provide the necessary control of the ventilation system.

    I have eliminated the connection to the Infinity unit, installed a stand alone control and my system now works perfectly. I have proper ventilation and proper humidity for my climate in the winter.
    We have about 10 days a year where an EVR would be nice but for 355 days an HVR is the correct ventilation unit in Minneapolis. On those 10 days I run the A/C to dehumidify.

    My system is sized properly, additionally I have a hybrid system with a heat pump and a 3 stage high effecient furnace. My supply air temp is around 100 degrees so the heating system has a small drying effect.

    Running your EVR constantly may; A)ventilate properly, B)under ventilate, or C) over ventilate.
    Without testing, measuring, and calculating what the proper volume of air which is required for your situation and measuring the amount of air the ventilator provides and factoring in the occupancy load and life style, you are just guessing.

    You need to have control over the ventilation device so you can control the volume of air you are exchanging in the house. Additionally you can adjust is volume of air - by fan speed and duration/runtime. A you want to be able to easily change it if the situation changes, like a party with 20 of your closest friends or a teenage sleep over... Chances are you need to crank up the ventilation...
    OR if you have one or two adults who don't cook and take their showers at the gym, in a 3000 sq ft house you need less volume of air being exchanged.
    You have to have this kind of control for the system.

  2. #41
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,739
    Quote Originally Posted by Energyauditor View Post
    TEDKIDD
    We have about 10 days a year where an EVR would be nice but for 355 days an HVR is the correct ventilation unit in Minneapolis. On those 10 days I run the A/C to dehumidify.

    THAT IS NOT JUST CLIMATE DEPENDENT, IT DEPENDS ON THE HOUSE TOO. BIG QUESTION IS DOES THE HOUSE EVER NEED HUMIDITY ADDED?

    A SUPER TIGHT HOUSE MAY NEED AN HRV IN MN IN WINTER BECAUSE IT IS TRYING TO SHED MOISTURE. BUT SINCE ADDITIONAL MOISTURE IS NICE FOR OUR LEAKY HOUSES, THEY BENEFIT FROM ERV. (As others have pointed out, you have a leaky house or you wouldn't be adding moisture, particularly with high occupancy. Just because you are below 70% Building Airflow Standard doesn't really mean "tight" except from a ventilation rule of thumb discussed below.)

    REMEMBER, MOISTURE IS LATENT HEAT. ADDING IT AND LOSING IT IS HEAT LOSS, SO I THINK ADDING LESS IS BETTER. shophound/beenthere - am I right about this?

    REMOVING IT DEFINITELY TAKES ENERGY. IN SUMMER WHEN DEW POINT IS HIGH AND THE A/C IS NOT RUNNING, YOU DON'T HAVE TO RUN THE DEHUMIDIFIER SO MUCH. DO YOU HAVE A DEHUMIDIFIER? DO YOU RUN IT ALL SUMMER?

    My system is sized properly, additionally I have a hybrid system with a heat pump and a 3 stage high effecient furnace. I KNOW WHAT SYSTEM YOU HAVE, IT'S A REALLY AWESOME SYSTEM. IF I HAD FORCED AIR I WOULD HAVE THAT SYSTEM, OR BE JEALOUS.

    My supply air temp is around 100 degrees so the heating system has a small drying effect.

    THIS CONFUSES ME, WHAT DO YOU MEAN BY DRYING EFFECT?

    Running your EVR constantly may; A)ventilate properly, B)under ventilate, or C) over ventilate.
    Without testing, measuring, and calculating what the proper volume of air which is required for your situation and measuring the amount of air the ventilator provides and factoring in the occupancy load and life style, you are just guessing.

    THAT'S CORRECT, I AM. BUT SO ARE YOU. THE CALCULATIONS ABOVE ARE JUST GUESSING. WITHOUT ACTUALLY MEASURING AIR QUALITY IT'S ALL JUST RULES OF THUMB.
    FINALLY, I COMPLETELY AGREE THAT HAVING MORE CONTROL OVER SPEED AND TIMING IS PREFERABLE.

    PERSONALLY I HAVE 15 MINUTE TIMERS IN THE BATHROOMS THAT BUMP TO HIGH AND THE FANTECH MULTI-FUNCTION CONTROL IN MY BEDROOM THAT ALLOWS ALL KINDS OF DIFFERENT RUN PROGRAMING. I JUST LEAVE IT ON LOW MOSTLY.

    AND WHEN I DID TEST MY IAQ THE DOG CLEARLY SHOWED UP, BUT NO VOC ISSUES.
    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.

  3. #42
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,368
    Quote Originally Posted by Energyauditor View Post



    My system is sized properly, additionally I have a hybrid system with a heat pump and a 3 stage high effecient furnace. My supply air temp is around 100 degrees so the heating system has a small drying effect.
    Weather a heating system's supply air temp is 80° or 140° it has no drying effect.

    Once that air cools down to room temp, the air has the same RH as it did when it entered the furnace.

    With the only real exceptions being duct leakage or an ERV/HRV removing moisture.
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