Loud Heat Vent

It's getting pretty cold here so the heat has been running a lot.<br /><br />All the vents downstairs are closed but the residual heat from the furnace running and the warm air that leaks from the vents keep it warm enough in the basement.<br /><br />All of the vents in the middle floor are all the way open except for in a powder room. This floor is the coldest.<br /><br />Upstairs, I'd like to close half of the vents in order to force more warm air to the middle floor except when I close or half-close the vents, the air moving through them whistles just enough to be extremely annoying.<br /><br />How do I quiet the vents down when they aren't fully open?<br /><br />Thanks,<br /><br />Josh

Re: Loud Heat Vent

Depending on where the air handler is located in relation to the duct trunk design will dictate the design air flow.Each systems fan in cfm is sized to move so much cubic feet per minute per btu of required heat for a given space.That said ,pinching down on air registers too much without opening others will resrtict this predetermined volume of air.Hence the whistling sound from the upstairs diffusers.<br /><br />Is this a split system or just a single?Just one air handling fan? Have you ever run it with all of the diffusers open? Unless the air handling system was originally installed correctly ,at times it can be difficult to adjust each register to the optimal setting to achieve a perfect temp balance.Best advice I can come up with is to try several combinations of register settings until the best one can be achieved.If you need to have one completely or mostly closed down to attain this,try to have it be one that is not within ear reach to be annoying.<br /><br />One other thing,is to insure that the fan cage itself is clean and its vains are not built up with crud.This can measurably decrease the fans cfm capabilities and reduce efficiency.<br /><br />In summation,the design size and application should be able to handle all floors without a problem.Thermostat location is also a factor in satisfying the ballance between floors and rooms.One that is generally as close to the return air grill as possible is the most common install.

Re: Loud Heat Vent

Check the ducts where they split off from the main overhead duct in the basement. Hopefully you will find that they contain a damper inside of them. It will look like a wingnut with a slotted screw head in the center from the outside. It is a large rotating flap type door on the inside. <br /><br />If you have these in the ducts that run to the top floor, you can adjust the airflow to those ducts by partially closing them. Turning the screw head crosswise to the duct, will close it off. Turn it parallel to the duct and it will be fully open.<br /><br />If you do not have any dampers in the ducts, you can install them. They are only about $6 each.<br /><br />I adjusted mine by opening the room registers 1/2 to 3/4 open.<br />Then opened all the dampers in the basement.<br />Monitored the room temps as the furnace cycled on and off throughout the day.<br />For the hot rooms, I closed the dampers 1/4 of the way.<br />This reduced airflow to that room and increased the flow to the other rooms. <br />The next day I fine tuned it alittle.<br /><br />Done.<br /><br />By leaving the room registers in the 1/2 or 3/4 open position throughout the process, you build in the ability to warm or cool each room with the room registers to account for personal preference or severe weather conditions.<br /><br />I also completely close the registers and dampers to the rooms that I do not want to heat. I just open them when I have overnight guests.

Re: Loud Heat Vent

One possible problem with closed vents and forced hot air heat is the furnace overheating due to insufficient air flow to extract the heat fast enough from the furnace heat exchanger. When this happens the furnace overheat protection circuit becomes the heat shut off device rather than the thermostat. You can verify this by closing several vents and noting if the furnace double cycles, that is after it shuts off it immediately starts another heat cycle as the thermostat calls for heat which wasn't satisfied by the last heat cycle. If not then your idea will probably work. There is also the possibility that you may actually reduce the furnaces efficiency since the heat output stays the same and has to go somewhere, possibly up the chimney through the heat exchanger wall.

Re: Loud Heat Vent

As Roscoe said, check the ductwork for dampers. Likely all you'll see is a little handle on the side of the duct. Moving the handle in line with the duct, will open the damper. Moving the handle so it 'crosses' the duct will close it, and any position in between is partially open. I had the same problem with the whistling in my house, so I opened all the registers and adjusted the dampers. No more whistling, except for my drafty windows!

Re: Loud Heat Vent

In my house I open the basement vents in the winter and open the middle floor to about half way. the upstairs vents I adjust depending on the weather. In the summer I reverse this.<br /><br />The heat from the basement will flow up to the main floor. Thats my rationale.

Re: Loud Heat Vent

Thanks for the advice, folks. I'm always messing with that damper to try to get it in the perfect place but it never seems that I can get it just right. <br /><br />I think the best advice is to just open all the vents, close the damper, and start adjusting from there.<br /><br />Another thought I had is I've seen filters that go in the heat vents (not the furnace filter, but actually in the vent). I wonder if that would slow the air down enough.<br /><br />Also, they advertise duct cleanings all over the place. Is this a waste of money? The house in 9 years old and as far as I know, they have never been cleaned. The vent outputs are never dusty and the intakes get cleaned whenever they are dusty.<br /><br />Thanks again.

Re: Loud Heat Vent

Don't know if the duct cleaning is worth the money or not.<br />I know plenty of people that have owned their houses for 30-40-50 years, and none of them have had theirs cleaned. Both of my grandparents houses have not had the ducts cleaned since they have owned them, approx 65 years.<br /><br />My house was fitted with a furnace and ductwork in 1954. Doubt that it has ever been cleaned.