I am looking for a mechanical ventilation solution that is a step above the single supply or exhaust fan which is set to the required 62.2 rate. On the flip side, it must be something that is similar or just above the price for single supply/exhaust. 

Has anyone used an inline fan which is on a small 4-6in duct going from exterior fresh to return plenum? Seems like you could get an inexpensive low power fan along with a simple control which will run continuous (or intermittent according to 62.2 intermittent guidelines). I like this because you can then filter the air and distribute the air throughout the house. I don't want to use the air handler because the majority are not ECM motors and are too expensive to retro unless you are already replacing your AC.

I am looking for model numbers of the fan/controls you use for this.

Open to other suggestions and I know there are much better ways...yada yada...but I am specifically looking for an intermediate solution that doesn't bear the cost of dedicated ductwork or an expensive ERV/HRV, while being a step above simple exhaust/supply.

Thanks for your replies

PS - I am in Hot/Dry climate with primarily cooling loads

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I do this all the time with just  a damper and  use the stat to move the damper as the timer.     When very cold or hot  some time will bring in to much air as the AC may not be big to off set the load extra.   I use a normal closed 4-5-6-7-8 in damper  then dump it into the return then the air cleaner  then air handler/furnace.   I use the Honey well IAQ stat what has 62.2 rate in it.      Down side with this is  on a 6" pipe 10' from outside will bring in 175 CFM next to outside wall - If the outside temp is to low I cranked a heat exchanger  the 1st  sub 0' night.   If its raining outside and damper is open  YOU can bring in 100% RH air  and can lower the total BTU's  on the AC side.   Just reset the Stat  for less open time.  This will make the building positive  and blows the dirt and stuff out.   In Midwest will raise the bill 15-25%  for both heat and cool.  

I don't really view this as viable solution due to the use of the air handler. If ECM motor may be ok, but otherwise to much energy hit from air handler motor. 

I did find a Panasonic WhisperLine Inline Ventilation Fan 120 CFM which pulls 36W and only 1 sone. Seems like this combined with a good controller and a damper would be a good way to bring fresh air into the duct system. Anyone see any potential problems? Maybe at a lower CFM setting it would draw less than 36watts?

Couple of things to think about with the ventilation supply to the return approach:

  1. The motor in your in-line fan will be effected by the big air handler blower which is likely to reduce its life which is the primary reason why this approach is usually just a pipe to the outside;
  2. The ventilation ducting is going to be small relative to the size of the house ducting.  The house ducting is (or should have been) designed to handle the larger volume of heating/cooling air (maybe 1000 cfm).  When the smaller flow blows through it, its velocity will be significantly reduced which may or may not be a good thing;
  3. When the air handler fan is not running, your supply air will circulate through the return ducting, missing the filter and conditioning elements, and may feel really drafty;
  4. It is really hard to determine how much ventilation air is actually being delivered to the house.

So one thing you might consider is the AirCycler's latest controls.  The G2 which operates the air handler blower that you can set up with the pipe to the outside, etc.  It will monitor the run time of the air handler for ventilation operation.  If the air handler has not run enough to satisfy the ventilation requirement, the ventilation function is transferred to the FanConnect control which turns on a bath fan to complete the need.  The power hungry HVAC fan doesn't run any more than it did before.  In the spring and fall, the bath fan will be the primary ventilation system, using much less power.

The hardest part of this is running the wires between the two controls.  And it's still hard to know how much ventilation air you are accomplishing, but its a thought.

Thanks for the input Paul. I think that will be a good solution and is better than just a fan alone.

Depending on the size of your house, this Panasonic ERV might do the trick:


paul your I like your answere


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