Get The Popcorn…

On July 29, 2010, in news, by jake
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Todays high tech TV and sound systems have a lot of computing power and lots of amps to portray the sounds the Director wanted you to hear. A byproduct of all those components can be tremendous heat build up, which potentially could damage your equipment.

The best way to alleviate heat build up is of course to evacuate the air from the enclosure or room the equipment is in. Typically installers will install a thermostat in the room, then put a remote fan above or below connected with duct to pull air out.

S&P inline fans:
http://www.hvacquick.com/products/residential/AirFlow-Boosting/Inline-Air-Booster-Fans/SP-TD-Series-Inline-Fans

Of course we need cooler air to come in and replace what we have taken, so a popular solution is to install a grille down low in the access door. This allows air to come from the house and absorb the heat being produced. Sometimes we even add a filter to this door grille to keep the dust from building up on the components.

This will also work with servers, and other heat generating electronic equipment. Some benefits of proper heat dispersal is better performance and longer life of the pieces.

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Recommendations for bathroom ventilation sizing can vary considerably between manufacturers and competing standards.  Some of the newer recommendations allow for low ventilation rates over long periods of time as opposed to the typical 8 air changes per hour. 

We prefer 8 air changes per hour as A MINUMUM and here is why:
When moisture is introduced into the bathroom it has an annoying tendency to get diluted into the entire air content of the space.  With low CFM (background) ventilation that moisture will eventually be exhausted, but in the meantime it will linger in the air and potentially condense on colder objects such as walls and fixtures.  Once it’s in liquid form on your walls it takes A LONG TIME to evaporate it again, not to mention the potential long term damage to the bathroom.

So what do WE recommend?
– minimum of 8 air changes per hour (more is better since the extra CFM typically comes at very little cost; nothing wrong with 10 or 12 air changes per hour)
– 100 CFM minimum per bathroom, no matter how small it is
– multiple grilles in larger bathrooms to pickup the moisture/smells close to the source
– keep the system quiet (inline fans!!) so that you will use it
– install a timer and leave the fan running for at least 20 minutes after leaving the bathroom

And remember, the standards are there for the builders and not necessarily for you.  Keep the moisture off your walls with adequate CFM and you will avoid mold issues.

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ASHRAE 62.2 — What is it?

On June 30, 2010, in solutions, by radek
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ASHRAE 62.2 “Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings” is the U.S. national minimum ventilation standard.  Note that not all states require it or may apply it differently so check with your local building codes to see what they require.

The standard requires low-level, continuous ventilation in a home using a whole-building fan or other ventilation system. Intermittent whole-building ventilation can be used as an alternative. Note that the standard uses the term “whole-building ventilation fan”, not to be confused with the term “whole-house fan” which is a different product (see AirScape whole-house fans on hvacquick.com.

To calculate the required flow for continuous ventilation, count 1 cfm (cubic foot per minute) per 100 square feet of floor area of the house. Next, multiply the number of bedrooms plus one by 7.5 cfm (cubic feet per minute). Then add those results together. For example, a 2,000-square-foot house with three bedrooms would require 50 cfm (20 cfm for the building area plus 30 cfm for the 3+1 bedrooms).

Typically HRVs or ERVs are used to meet the standard, but bath fans are acceptable as well.  There are additional sound and minimum cfm criteria that bath fans must meet in order to be allowable.  Fantech and S&P inline fans are a good option due to their low sound levels and available 62.2 control options:

http://www.hvacquick.com/products/residential/Ventilation-Accessories/ASHRAE-62-2-Controls

An online version of the standard is available at the ASHRAE website (www.ashrae.org).

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Why you need ventilation.

On June 30, 2010, in solutions, by radek
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Older leaky buildings permitted sufficient air change (fresh air infiltration) to remove pollutants (such as carbon dioxide, moisture, mold spores, formaldehyde from building products) by the natural forces of wind and stack effect.  Newer, tightly built homes do not allow this air exchange.

The best way to introduce fresh air into a home is through the use of an HRV or ERV.  These products allow for balanced ventilation, same amount of air is exhausted as brought into the house, and the majority of the heat/cool is recovered from the exhaust stream into the incoming air.  You get the best of both worlds — good air quality and low operating cost.

Heat Recovery (HRV) and Energy Recovery (ERV) units:
http://www.hvacquick.com/products/residential/Indoor-Air-Quality/Residential-HRV-ERV

Fantech heat recovery units

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