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## CFM's

Whats the Minimum CFM's for exhaust when balancing a EVR/HRV I know the amount is determined by the number of exhaust point divided by the total amount of CFM's of the unit i.e 200/6= 33.3 cfm per exhaust point but how low of CFM's would be allowable where you would still have proper ventilation ?

2. Wouldn't that depend on what your house needs.

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So if my house for sake of argument needs 200 cfm's and I install 10 exhaust points with each point of exhaust having only 20 CFM's that would be sufficient even if one or more of the rooms was 400 sq. ft. ?

4. I always thought that you had to balance the needs of the space the exhaust opening is going into, ie small bath, large kitchen etc with the total amount to be exhausted.

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Originally Posted by DanW13
Whats the Minimum CFM's for exhaust when balancing a EVR/HRV I know the amount is determined by the number of exhaust point divided by the total amount of CFM's of the unit i.e 200/6= 33.3 cfm per exhaust point but how low of CFM's would be allowable where you would still have proper ventilation ?
I can't say I've ever used that formula.
As beenthere says, it depends on what the house needs.
It also depends on what the requirement of each exhaust point is.
For instance, a large kitchen would require more ventilation than a powder room.
The HRV ductwork should be sized and installed accordingly.

Sorry kls-ccc.....I'm a slow typer

6. Now I might understand your question a little bit better.

Bedrooms would need enough for the number of people.
Bathrooms as low as 25CFM.
Common open areas don't need balanced to each other as much. Since natural air currents will help mix the room airs.

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Originally Posted by beenthere
Now I might understand your question a little bit better.

Bedrooms would need enough for the number of people.
Bathrooms as low as 25CFM.
Common open areas don't need balanced to each other as much. Since natural air currents will help mix the room airs.
There you have it.
Although the HRV is sized according to the volume of the home, exhaust points are located only where they are needed.

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Originally Posted by DanW13
So if my house for sake of argument needs 200 cfm's and I install 10 exhaust points with each point of exhaust having only 20 CFM's that would be sufficient even if one or more of the rooms was 400 sq. ft. ?
200 cfm might be 2 or 3 times more than typcially needed for continuous ventilation. See ASHRAE 62.2

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Originally Posted by dan sw fl
200 cfm might be 2 or 3 times more than typcially needed for continuous ventilation. See ASHRAE 62.2
Good point.
I haven't seen ASHRAE 62.2.
But, I seldom see anyone operate their HRV continuously.
Around here, they are used as glorified exhaust fans.
Therefore, we size them to maximum exhaust capability.

And...It's the LAW in these parts.

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Is ASHRAE 62.2. available for reading somewhere on the internet The full version ?

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## Reasonable ventilation

Originally Posted by DanW13
Is ASHRAE 62.2. available for reading somewhere on the internet The full version ?
no

http://www.ashrae.org/pressroom/detail/16048

Only VERY LARGE home would need > 90 cfm continuous ventilation

http://www.e-star.com/publications/a...ae_11.2004.pdf

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Originally Posted by dan sw fl
200 cfm might be 2 or 3 times more than typcially needed for continuous ventilation. See ASHRAE 62.2
I'm not sure if 200CFMs would be too much or just boarder line since both me and the wife are smokers thou it's mostly contained in the main living area and do not smoke upstairs in the sleeping area of the home. I was thinking the Renewaire EV-200 would be just a tad much but am rethinking maybe going with the EV-130 and I am going to operate the unit continuiously and would possibly have the baths connected thou here again I'm thinking of running the baths on a seprate inline fan along with the Kitchen exhaust so I'm still pndering just how to set-this all up.

If I lose the inline fan idea and run everything thru the EV 130 or 200 and use the inline fan for just the kitchen exhaust so I guess it all depends on which is my best option but am open to suggestion .....

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## Dang - Pollution control is not my fortay

Originally Posted by DanW13
I'm not sure if 200CFMs would be too much or just boarder line since both me and the wife are smokers thou it's mostly contained in the main living area and do not smoke upstairs in the sleeping area of the home. I was thinking the Renewaire EV-200 would be just a tad much but ...
1. Quit smoking
2. Smoke outside @ > 14'F
3. EV-200 is likely N O T too much.
I would only run noon - 10 pm or to fit your schedule.

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