Adding a duct to a hanging heater, why not?

[tryme96z]

I am looking for input from HVAC people on why it would be a bad idea to extend a single duct trunk off of a hanging garage heater. The manufacturer of these heaters seems to frown upon the idea. Though it seems like running a single duct across the back of the garage with a few registers pointing down would help balance the heater in the area.

The biggest reason I foresee that this is a no-no is because there is a fan pushing air over the heating element that may not have the power to push air through the ducting. And more than likely adding a blower fan would push to much air over the heating element cooling it down too much.

 

[finn]

Price out a regular gas furnace if you feel the need for ducting.

last time I checked, an 80% unit wasn't much more expensive than a 75k btu hanging heater and they adapt to plenums without cobbling up a half assed home brew setup.

 

[AldeanFan]

Just use a box fan or ceiling fans to circulate the air. Houses need duct work because you are heating various rooms. A garage is one big room so the air should circulate fine.

 

[LS6 Tommy]

Propeller style fans aren't designed to develop static pressure. Trying to use one in for a ducted system will just cause your limit to trip because there will not be enough airflow across the heat exchanger.

Tommy

 

[Showkey]

Price out a regular gas furnace if you feel the need for ducting.

last time I checked, an 80% unit wasn't much more expensive than a 75k btu hanging heater and they adapt to plenums without cobbling up a half assed home brew setup.

Often you can get a 96+ Furnace for less than the hanging units and hanging are 80%. Added bonus easy venting. Even if ducting not needed furnace and $50 plenum is a good solution.

http://www.alpinehomeair.com/viewcategory.cfm?categoryID=128