Dryer vent hoods come in a multitude of styles and end up in one of three locations on your home: the roof, the soffit or the wall. The objective of a vent hood for the dryer is basically two fold; prevent back drafts and prevent bird or rodent entry as well as nest building. In facilitating these capabilities a prevalent result is a vent hood that promotes lint build-up and creates excessive back pressure.
A vent hood or fitting that creates excessive back pressure not only lengthens the drying cycle but accelerates dangerous lint build-up. Higher energy bills and increased risk of fire become the obvious outcome. Until now, there was no assessment of the back pressure that these popular vent hood designs and fittings provide. The below chart provides the actual difference or delta (∆) of air pressure measured with a Magnehelic Gauge* before and after the fitting was attached (Differential Pressure). The higher the value, the less efficient the fitting is. These days, being energy efficient is important step in the direction of drying smart. Consider these values when shopping for a dryer vent fitting or hood.
|Fitting Type||Description||Model ID||Thumbnail||Buy||Airflow Reduction (wci)*|
|Roof Jack Plastic||ROOFJK||N/A||.35|
|Popular Broan Style||Not Carried||N/A||.30|
|Typical 4" Wide Goose-neck||Not Carried||N/A||.45|
|New Mushroom Style||Not Carried||N/A||.25|
|Wall||Dryer Wall Vent||DWV4||.00|
|4" Louvered Vent||GH4W||.08|
|No Nest Vent||NO NEST||.01|
|3 Louver Opening Vent||HS4W||.03|
|Dryer Vent Closure||DRYER VENT||.60|
|Standard 30° Wall Flapper||Not Carried||N/A||.20|
|Eave||Under Eave Vent||EVEVENT||.10|
|Fittings||Sectioned 90 Degree Elbow||ELL-4||.15|
|Dryer-Ell 10 Inch Radius 90° Elbow||LT90||.05|
|Dryer-Ell 10 Inch Radius 45° Elbow||LT45||.05|
|Lint Trap||ECCO Lint Trap||.15|
|Periscope Style Connector||Not Carried||N/A||.50|
|Flex||Foil Wire Bound||FOIL-45||.35|
|Semi Rigid Alum Flex||ALUM-439||.10|
|Semi Rigid Alum Flex||ALUM-448||.10|
*Magnehelic Gauge: A sensitive differential pressure or vacuum gauge manufactured by Dwyer Instrument Co. that uses a precision diaphragm to measure pressure differences. This gauge is manufactured in specific pressure or vacuum ranges such as 0 to 2 inches of water column. Airflow was provided by a typical residential clothes dryer.