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Improved air quality


Fresh Air and Energy Recovery

311 Varnum has an additional piece of HVAC equipment: an Energy Recovery Ventilator (ERV).  In the summer, the ERV exhausts cool indoor air.  This precooled air is moves through the ERV and it transfers some of coolness to the warm incoming fresh air.  In the winter, the opposite happens, warm indoor air is used to pre-heat the incoming cold fresh air.  Along with the heating and cooling transfer, humidity is transferred as well.

The benefits of an ERV are many

>  A constant supply of fresh air is introduced into the home, improving air quality.​

>  Incoming air is pre-treated, and therefore the HVAC has to work less, using less energy.​

>  Humidity is modulated and maintained within an appealing 40-50% range in all conditions.

Local Exhaust and Direct Venting

Baths and kitchens generate a high humidity load for a home. In addition, kitchens are one of the chief places smells, and contaminants are created in a home.

311 Varnum has not only local exhausts at all of these locations to remove humidity and contaminants at their sources, but the baths have push button timer controls automatically controlling how long a fan will stay on. 

It is very common for homes to have a microwave recirculating fan, that provides a modest amount of filtering of cooking air.  311 Varnum has the kitchen direct vented to the outside of the home, removing humidity, smells and contaminants to the outside and helping keep indoor air fresh. 


Performance Testing

​One of the most important parts of a LEED certified home is the third party testing that is performed on HVAC system components.  It is extremely common for bath fan vents to get crushed, get ripped up or not even installed during construction...then they do not draw the air they should even though they sound like they are working.  This means more humidity and more smells and unwanted particles remain in a home, decreasing it's air quality.

In this hopefully LEED certified home, the following is verified by the tests:

>  All bath fans draw at a minimum 50 cfm​

>  Kitchen exhaust draws a minimum of 100 cfm​

>  ERV draws the required CFM


HVAC filtration standard is rated in Minimum Efficiency Reporting Value (MERV).  The higher the value, the more smaller sized particles a filter will remove.  311 Varnum has a MERV-12 filter which is rated to remove  80%-89.9% of 1.0-3.0 micron sized particles and 90% or greater 3.0-10.0 sized particles. To put this into perspective, typical HVAC filters are in the MERV 1-4 range, and most do not advertise their rating as they remove very little from the air delivered to the home.

Construction Contamination Control

During construction all HVAC ducts were sealed and the system was not in operation until all painting/sanding and other dust and mess generating activities were completed.  Additionally, the home was flushed for 48 hours after all construction was completed to further remove contaminants.

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