View Full Version : hot air vents - to cover or not to cover?

09-01-2011, 11:07 AM
Cold weather's approaching, so we're using our furnace at night. We noticed the floor vents are just grates, really, totally open to the ducting, so things can easily fall in. We taped some white register filters to the inside, to catch anything falling through and help stop dust from blowing in. We want to buy some adjustable registers to regulate the hot air flow. The way it is now, the bedroom and bathroom get too warm with the main area staying too cool. (oh, especially the bathroom, man!)

So, question: is there any reason I shouldn't regulate the vents as I please, keeping some closed, or halfway closed, etc? Would the furnace object? I want to totally block off the vent by the back window. It sits directly underneath the sofa. There is another one just a few feet away anyway, right in the middle of the livingroom floor.

Next question: there is a wood grate in the wall above the front closet door. What is this? Does it draw air in for the furnace?

Thanks, guys! :)

PS I learned from our other trailer that I need to get plastic floor vents - those metal ones are HOT :eek: on bare feet!

09-01-2011, 12:54 PM
From what I have gathered, furnace manufacturers warn against both using filters which restrict airflow and also using vents for the same purpose. I personally do not do use adjustable vents.

From Suburban...Can I close off a register so more heat goes to another part of the vehicle?No, this is not recommended. Doing so will cause improper furnace operation and possible overheating of the furnace.

That being said, many people do use them and are happy with the results.

I believe the grate you are referring to is a cold air return.

09-01-2011, 01:28 PM
Thank you! Can I please also hear from others who DO use the filters and/or the adjustable vents. Have you personally found that it has affected your furnace's operation or safety or anything? Well, I guess, really, SJH's reply of many people use them and are happy with them, really does answer my question, doesn't it? Oh, will my furnace maybe let me know that it's unhappy, by overheating and shutting down or something?

Oh, right, a cold air return - I knew that :o Not that I've ever understood what it does, but that's okay .. I know enough that you need one and I know enough not to "obstruct" it. Should it be called a "cold air intake" - it sucks the air out of the room, the furnace heats it, and blows it out the vents as warm air? Again, a reply not necessary ...

09-01-2011, 01:58 PM
I use adjustable floor register vents in the bedroom and bathroom. I remember the dimension as 10 inches by 4 inches in my Landmark. I have not seen any issues with the furnance overheating due to low air flow. The air is redirected down to the step, kitchen and rear living area vents. It does provide better hot air distribution to the back living areas. Like you, I got too hot in the bedroom/bathroom without the adjustable vents.

The grate above my control panel does not serve as a cold air intake for the furnace. I have removed it a couple of times to add additional items (battery moniter, inverter control panel, etc) to my control panel. The top of my control panel cabinet is blocked off from the basement (furnace location) due to the closet indentation below the control panel. There are two skinny passages on the edges of the cabinet that pass main wire looms and house the thermostat (left side), but these are too small and obstructed to provide any air flow back to the furnace. IMHO. The upper grating is available to vent any heat load from the control centre, however I think that this is small.

The return air, or cold air intake to the furnace just draws out of the basement, and there are sufficient draft passages to allow air flow from the living area of the coach back to the basement (stair step drawers, etc).

Hope this helps.


09-01-2011, 02:13 PM
Thanks heaps, Brian! Another project to add to my poor hubby's to-do list. My job is to add to the list, his job is to stroke them off (hopefully not before he's done them :D )

Take good care - Lorna

09-01-2011, 05:40 PM
I've replaced all the floor vents with adjustable plastic ones. Our "most effective" vent is the one by the rear window, that often is under part of a recliner! So I close that one off, forcing more heated air to the others, and hopefully prolonging the life of the recliner.:eek: The other are more "directed" which is helpful in my opinion. (for example, the bedroom vent directs hot air back toward the room instead of toward the wooden bed base.)


09-01-2011, 06:06 PM
I replaced all of the floor vents with metal adjustable ones (no filters). That was in 2009. No problems with the furnace and no burns on my feet. 4"x10" is the size. You can see where the cold air return is on my 3670. The furnace is directly below that vent.


09-01-2011, 10:59 PM
I agree with John. I replaced all mine with metal adjustables and have had no problems at all. I can put the heat where I want it.

09-02-2011, 10:25 AM
We use the metal adjustables ones from this company. They are HL's supplier. Good people to work with they ship direct to you. I would remove the return/cold air vent and see what is behind it. If your furnace is behind it...do not put any type of filter in or behind it. The filter could come apart or be sucked in to the furnace with bad results. It would also restrict the air flow.

The size is 10x4..but that is outside measurements. The ones on the website I posted are the ones you need. You can use a phillips screw driver to replace them but a square driver works better.