Bad idea to put fans in air duct?

Im not sure what its called but the end of the air duct I guess. I wanted to put some computer fans in them and I wasnt sure if this was a bad idea. My rooms hot and the rest of the house isnt. I get cool air through there but doesnt come out far enough to get around the room, I figured if I put fans it would help and im not sure if fans in there is a bad idea. I already have a fan in my room but doesnt help.

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MJCino7 years ago
Hmm . . . yes and no's all around. A tiny computer fan? Wouldn't do it for you. You would probably need to cover at least most of the duct opening up with fan before you would *potentially* have a noticeable effect. Maybe a box fan? There's no reason fan-powering should hurt your ductwork, but it may pull more stuff from inside your ductwork into your room and the fan you placed there, likely meaning that the fan would need to be cleaned and might break down sooner. A fan may cause your heating system to poorly function if the fan were to pull too much air from the duct feeding your room to the point of the exclusion of cooling elsewhere in the house. If you were to put the fan in front of a return duct (and it's hard for me to tell from a picture which direction the air moves), it's possible that you could damage heating or cooling equipment, but I would think it would be less likely if you were using your cooling equipment than if you were using your heating equipment. Putting a fan in front of the return ducting would essentially cause your air handling system to work in reverse and possibly starve the system of air it may need. Other options? It's a good bet that you probably don't have a return and supply duct in your room. One pulls air FROM a room, the other pushes air INTO the room. Some homes only have one return grill anywhere in their house. Let's imagine you had a bedroom that was somewhat airtight - not a hard stretch of the imagination in a room with a closing door. The air supply duct going to that room is not going to push any more air into there when it can't overcome the pressure it would take to push that volume of air out. SO - if air can't leave your bedroom, no new cold air will come in your bedroom. If you open your bedroom door a crack or more, it may help. Another option may involve interacting directly with the ductwork somehow. It's possible that there is a damper - a piece of metal which can be rotated to shut off air down a duct - in the duct feeding your room. If you can look at any parts of your ductwork, look for something that looks like a handle coming DIRECTLY off of the outside of your ductwork. Do NOT mess with any handles you are unfamiliar with on your furnace or air conditioner. Handle running parallel to the duct usually means fully open - the direction of the handle mimics the direction of the damper. It may also be possible that your air system was poorly conceived and designed. If the duct feeding your room is too small relative to how big it should be and how big the ducts feeding most other individual air registers, it will not give you enough air. It's also possible that there was no way that good design would have put much air into your room if your room is just too far away from the air system and too many other ducts get to the air before it gets to you. Fortunately, there are the two problems with the best likelihood of being helped by fan-powering that duct.
smccleme5 years ago
I have done exactly what you are considering. It works like a charm. Cutting the top of a plastic container, with some weather stripping around the outside fits the round duct perfectly. Using on old DC plug adapter powers the fan. At 2.5w it costs about half a cent a day to run 24 hours, and provides similar airflow to the furnace blower. And when the furnace blower does click on, hold on to your hat!
Re-design7 years ago
A computer fan would be too underpowered. What you need is a "duct fan" it's a fan built into a piece of round duct. You cut the duct and install the fan. then when it is on it pulls more cooled air into the room and the throw is better since it is moving faster. My guest room is on the end of the system and was under cooled/heated until I installed a fan in the duct. Check out this link .
MJCino7 years ago
Oh, gods, I'm so sorry that my answer is now so unreadable due to Instructibles removing my formatting. Imagine that there are paragraph breaks . . .
If you want para. breaks and other formatting you have to click on "Rich Editor" after you click on answer. I hate the new plain editor also.
aerilus7 years ago
have the same problem the reason is most likely that you computer is turned on at least thats my reason. i cant see it hurting anything but the air system is positive pressure fed by a fan blowing air over a coil putting fans in a vent isnt going to make any more impact than putting them anywhere else I suppose a large enough fan would interfere with the main fan blowing air over the coil and could create problems but pc fans arent going to exert any preassure that far back. best thing to do would be get a stand alone or a window unit which would create an independent system