As the title says - I have a 2400 sq ft 2 story home being built, I also have a split setup for my hvac - 1 unit in the basement and 1 unit feeding the attic of the 2nd floor.

I'm waiting for a final blower door test to conclude the correct size of my HRV, but I wanted to see everyone's opinion as to where to locate the HRV.

MY home is configured with bedrooms upstairs, and living space downstairs - My original thoughts are to ventilate the sleeping areas, and supply them with fresh air.

I might be over thinking this whole thing - because once the hvac starts running it will circulate the fresh air no matter where it enters the home.


Thanks in advance!
Dave
 

Blower door testing should have no bearing on the sizing of the HRV, since the locations and size of the leakage in no way guarantee ventilation air where it's most relevant/ needed.

Size it for the maximum ACH you think you might need, then operate it via duty-cycling/dehumidistat/whaddevah to achieve the indoor air quality that feels right. The ASHRAE specs for ventilation rates are usually WAY overkill for most non-smoking homes. In a tight house you'll still want pretty good kitchen and bath exhaust (and USE THEM consistently), but you can usually back off from ASHRAE rates by quite a bit and still have excellent indoor air quality, especially if you avoid the use of volatile organic chemicals in your building materials & personal habits (aerosol spray products are not a girl's best friend, even in an overventilate house.) In cold climates excessive ventilation rates will have a severe drying effect in winter. In most of he cooler parts of the US if you avoid smoking & VOCs you can run the HRV via dehumidistat control to keep it a comfortable & healthy 30-35% relative humidity @ 70F

Posted By Dana1 on 13 Dec 2012 10:15 AM
In most of the cooler parts of the US if you avoid smoking & VOCs you can run the HRV via dehumidistat control to keep it a comfortable & healthy 30-35% relative humidity @ 70F

I would modify that to say "...in most of the cooler parts of the eastern U.S. ..."   In the dryer parts of the western U.S., the HRV would rarely turn on if based on humidity levels rising above a set point.  

Posted By Lee Dodge on 13 Dec 2012 10:32 AM

Posted By Dana1 on 13 Dec 2012 10:15 AM
In most of the cooler parts of the US if you avoid smoking & VOCs you can run the HRV via dehumidistat control to keep it a comfortable & healthy 30-35% relative humidity @ 70F

I would modify that to say "...in most of the cooler parts of the eastern U.S. ..."   In the dryer parts of the western U.S., the HRV would rarely turn on if based on humidity levels rising above a set point.  

It depends on the volume to occupant ratio, and whether the occupants bother to bathe, eh?  

High house volume/occupant ratios can become a drying issue at high altitudes over the course of a winter, independent of ventilation rates. But at high volume/occupant ratios in a low-VOC environment backing WAY off from ASHRAE recommendations for typical homes does not present a health issue.  Some ultra -tight PassiveHouses use a combination of dehumidistat & occupancy sensor input to control ventilation rates to guarantee a minimum, but breathing & bathing humans put out a lot of humidity in the course of 24hours, and hitting high CO2 levels before the interior humidity hits 30% RH @ 70F in a hermetically sealed enclosure isn't very likely unless breathing is the only moisture source. (Buy some houseplants, and water them, eh?)

would you locate the HRV in the attic to feed fresh air to the bedrooms? or would you put the HRV in the basement to feed the living space?

Thanks!!!

HRV systems are usually ducted to where the ventilation (& exhaust) are needed most. It's common to install exhaust-only ducts in bathrooms, supplying ventilation air to the bathroom via grilles or jump-ducts (or sometimes a1/2-1" door cut between the threshold and bottom of the bathroom door), and supply-only ducts into sleeping areas, with return provided to hallways or common spaces via grilles/jumpducts, etc..

Where the unit itself is located depends a bit on how you want to route the ducts, but it's usually near an exteiror wall to limit the lengths of the runs for the intake & exhaust ducting to the outdoors.