Furnace closet ventilation

tinaambrozy · August 10

Our home’s utility closet is on the 2nd floor and houses an electric furnace and electric hot water heater. The closet is next to our family room and closet’s doors are vented so it is incredibly loud in this area when the furnace is running. Could we replace the vented doors with solid doors to reduce the noise? The furnace intake is in the ceiling of the 1st floor (directly beneath the furnace) and there is a vent on the side of the closet above the stairs. Here are pics of what I’m mentioning. The first is of the inside of the closet (the vent is on the lower right), the second is the 1st floor ceiling beneath the furnace, and the last is the vent above the stairs.

HydronicMike · August 10

The return grill in the wall may not be big enough.
You could have someone measure static pressure and see if it changes when the louvers on the doors are blocked off.
Or a cheaper, non technical way.
Tape plastic over both louver doors. Put furnace fan on high. Close the doors, leave it about a 1/2" open. If the doors suck shut, or pull in, you don't have a big enough return. If not, you probably do.
If it were me, I'd make a bigger hole in the wall, and put an actual return duct from the furnace to the wall.

PC7060 · August 10

The blower fan should not be that loud, may have a bad bearing. Can you attach audio clip of the blower motor?

Electric heating / hot water heater space do not require venting so solid door should be fine.

Agree with @HydronicMike that the wall vent seems small. Does it whistle when running?

Jamie Hall · August 10

If I'm reading @tinaambrozy 's message correctly, @HydronicMike , the return inlet is a grille in the overhead of the first floor, and there doesn't appear to be either an inlet or outlet in the closet at all.

If that grille in the overhead is large enough — like close to the size of the base of the furnace, which it looks like it may be, it should be ample — but one might check to see it if it really clean and open. Likewise the outlet grille.

Now all that said, it has been my experience with electric furnaces that they are LOUD. Do try @HydronicMike 's trick with the doors. If you find that there is little suction— little draught through the doors — then the next question is what the installation instructions say about distance to combustibles and requirements for ventilation of the s[pace. It may not need much, in which case substituting a solid door will help.

tinaambrozy · August 10

Thanks very much for the advice. We’ll try sealing off the louvers to see if the doors pull shut while the fan is running. There is not a whistling sound while operating and @Jamie Hall is correct that the return inlet is directly under the furnace to our 1st floor hall ceiling. The inlet is 20” x 14” and I can feel air being pulled in while the furnace is running. The wall vent is roughly the same size, but is not connected to the furnace.

tinaambrozy · August 10

btw - I tried to upload a video of the running furnace but was not able to do so.

HVACNUT · 10:15AM

They're electric appliances. You can sound proof the closet if you want. No combustion air needed.

Jamie Hall · 12:12PM

https://forum.heatinghelp.com/discussion/comment/1901777#Comment_1901777

True. But they stilll may have required clearances for temperature.

Furnace closet ventilation

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