Tuesday, July 26, 2011

Whole house Fan for a Philadelphia Town Home

Photo of a whole-house fan and its shutters, p...Image via Wikipedia

What is a Whole house fan?

A whole house fan can be a confusing topic for homeowner with homes that are not 1980 or new Subaru track house. There are fans designed to fit into the large attics of these newer types of home. These fans are what are generally referred to as whole house fans. The standard whole house fan will not fit into most of the housing stock found around the city.

There are ways to accomplish the same whole house ventilation in a home that are of an older design. Here is an example of a house that we added two 1500 CFM powered roof vents to. We then cut a whole from the attic to the second floor hallway. A whole house fan designed for a suburban home produces around 3,500 to 4,000 CFM for homes that average 3,000 SQFT. 

Here is the Access that we make into the attic. This Access hole will be covered by a grill after everything is completed. This home is at least 80 to 100 years old. It still has plaster and lath construction.  This home only has a tiny attic space. A fan sold as a "whole-house fan" would not fit into this space.

Here is a look up into the attic after the plaster and Lath has been removed. The hole in the roof is where the roof vent is located. We are going to remove the roof vent and install two powered roof vents. The two powered roof vents will move a total of 3,000 CFM of air out of the small attic space and the home. 

Here is that same roof vent viewed from the roof. We are going to remove this non-powered roof vent and add an attic fan kit in its place. This type of fan is commonly used to large vent attics in housing developments. The fans attach to the roof under the shingles or get mucked down onto flat roofs.  

The new attic fan is larger than the existing roof rent. We use a template to cut out the hole for the new Attic fan or powered vent. This is simple to cut with a sawzall or a jigsaw. You need to take special care not to damage the roofing shingles. You also need to know where the stricture for the roof is before cutting. 

This is a close up of the 1500 CFM powered roof vent before it is set under the shingles. It is often referred to a roof mushroom fan. The fan fit inside the center of the dome. Pulls air up the middle and vents it on the outside of the dome. This shape allows the air to get out without letting rain water in. 

Here is the completed roof fan. It was fitted to fit under the roofing shingles. The fan is secured with roofing nails and is water sealed with roofing compound. This turned out to be a very clean installation.  We still need to return to finish up the inside wiring. When this is done the two fans will act like a whole-house fan. Venting a house this way is a great way to save on cooling costs on a hot summer.

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  1. This new whole house fan changes the air cooling definition and also provide a natural fresh air. That's why it is well worth for using.

  2. Thanks to share this well informative blog with us.Keep sharing.I will keep share in future.
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  4. This looks good! What a fabulous idea! Thanks so much for sharing!! philly trip