one room is hot

Hi, I have this one room in my house that gets about 4-5 degrees hotter than the rest of the house. My home faces east and west so I was thinking since this room is the only room with a window on the west side, it was just getting so hot because the sun sets over there. But even at night it gets so warm in that room. What could be causing this and if anyone had this problem, what can I do to help fix it? I end up turning the AC down but the rest of the house is cold while this room is still real warm. I have tinted the windows and have put curtains on them with blinds.Thanks for any suggestions.

 

See if perhaps there is a damper that is shut closed on the branch that feeds the supply for this room.

Is air coming thru the register(s) in this room? Maybe a section got disconnected

You may also have a balancing problem here.

 

I have the same thing. Upper level rooms get hotter anyway due to the "stack effect".
And, when the sun is up and in the west, the trees don't sufficiently block the light.
This upper level NW room even stays warm after the sun goes down because of "thermal inertia" (the specific heat of the room air and the building materials and the furniture). Here's something to wade through-
http://en.wikipedia.org/wiki/Heat_ca...#Heat_capacity

I put in a window AC, but then I found out that the room was comfortable sometimes by just running the AC in the fan mode, even at 88 F, so now I just use a fan if I'm sitting in the room, and I moved the AC to the upper level NE bedroom. That's when I found that some window ACs are noisier than others.

We also have a window fan in another room, so if I open a window in this hot room the air flow in through the window in the hot room is just right to cool off, depending on where you are sitting.

A more drastic solution would be to install a booster duct fan for the room duct, wired to only run when the central AC is on. This wiring can be tricky.
I did this to solve a low-heat-in-winter problem in a ground-level family room, but noise level is sometimes a consideration with these fans. They make a metal/fabric/metal coupler to dampen this noise; it sort-of works.
The fan allows you to correct duct design and duct length problems, kinda' like caulking hides bad woodwork joints. You might want a two speed fan to give you more flexibility.

Try stuff out, from the least costly on up. It's worse if it's more humid where you are.

 

Air is coming through the vents and just as back information, this home is only 1 year old.

 

Booster fines Very seldom work! If your room is hotter than others you have a duct problem. This needs to be sized with a manel J. If your home is only one year old time to call the builder. Most homes are put in with low bid. Most are hacks that just put it up as fast as they can.

 

These are nothing more than suggestions, you have to get a skilled tech locally to help you make the right decisions!

Do everything possible to reduce the heat-gain in that room.
If that is not enough heatload reduction, do a heatload calc for that room to determine the BTUH required.

Then get someone to install, a larger than the duct used, take-off from the main trunk, using a properly sized duct to meet the BTUH demand of the room.

you could buy a long-radius 90-ell, (if one attaches to the boot), with turning vanes in it, also the boot & the SA register may need to be larger.(?)

You must have an extra good Return Air path from that room!
HVAC RETIRED -udarrell

 

ok thanks for the suggestions. I will probably just get an AC tech in to check out the room.

 

Thomas,
I have the exact same problem. The room is colder than the rest of the house during the winter, and hotter than the rest of the house during the summer. The builder made a recessed box ceiling, not allowing room to run supply duct work to the other side of the room. The supply registers are at the entrance to the room. When the AC kicks on it appears to pull the supply air out of the room too quickly not washing the room with cool air. I was told I needed to install a separate return in this room. Due to the raised boxed ceiling it would look stupid and I haven't talked my wife into it yet. She's going to freak when i install a window unit in this room so i can sleep. lol.

 

I wonder if that might be it. Not sure wat a "recessed box ceiling" is but the ceiling in this room is differently shaped than my other rooms. Its a tall ceiling where the walls go up to almost a point ( if that makes sense ). Since this room faces the front of the house a window AC unit is the last thing I want to do to cool it down. I currently have a ceiling fan and 2 floor fans running in it.

 

Could you mean "peak" rather than "point"? As in a vaulted ceiling? Does the ceiling line then go downhill, from the peak, down to the opposing wall where there it is back to the 8 foot height? How high is it up by the point, or peak? How many square feet is the room? How big is the register, and how many are there, and where are they located? Does the air blowing out feel as forceful as the air coming out the cold room's registers?

 

You are correct, it goes to a peak. Yes the side walls are 8 ft but the complete top of peak is a 10 ft ceiling. The air feels the same as the other rooms. I think I might know what it is, when the house was getting built I had them remove the closet which took up one side of the room and just expand the room. Maybe the register cant handle the extra square footage that was added..possibly.

 

I'll try to post a pic tonight and show you how my room design is affecting the cooling. I may not be able to figure out how to attach the pic, but i'll try.

 

To post pictures you need to first upload the pictures to a photo hosting site such as photobucket.com or villagephotos.com. and then post the public URLs for the pictures (or album) here. More pictures are always better than fewer

 

This is the problem we have with our bedroom. See attached photos.

 

Do you have a central cold air return out in some hall outside that door? If you run the a/c and stand at the door hanging onto say a 4 feet piece of toilet paper, while you are just inside the room, does the toilet paper really suck toward the hall outside the door?

I know of a similar layout and I am now curious enough that I am going to conduct some tests to see how air flow is able to distribute air around the room in a situation, like yours, where the incoming heat or cold has registers only closer to the door. Un-schooled logic would lead one to believe in such a case that the register air should just go out the door back to the cold air return, leaving the rest of the room the temp it started otu at. But as I said, in cases I have have seen this, this is not the case. Yet yours IS.

If that room leaks like a seive, THAT could have an bad effect, where instead of low pressure areas being created in the room, which would help distribute the air, the incoming leaky air would help channel your regsiter air right out the door.

With THAT said, then also stand in various places in the room, with the toilet paper (or you could use an incense stick and watch the smoke) and see if any air actaully goes deeper into the room, or if no matter where you are, if the air pretty much pulls out toward the door.

 

Thanks for the pics. I can see what your saying now. I only have one vent and no return in this room, so I will just find out what an AC tech suggests. Thanks again.

 

I hope we get to find out of any corrective measures.

I did conduct that test yesterday where I was going to see what kind of draw I got, with toilet paper hanging down to the floor, at the entry to a room with one register near the door, with central cold air return outside the door. To my surprise, there was no draw of the tp toward the (open)door! - even though plenty of draw next to the cold air return out in the hall! And after walking around the room and stopping here and there, back deep in the room, the tp actually looked like it was leaning back into the room, if anything, rather than toward the door, as you'd think it would. Thereby explaining how that room, with one register, near the door, can indeed warm up or cool down, uniformly everywhere, in that room, even though cold air return outside the door. This was an interesting discovery.

I advise anyone with problems like the poster to try the same test. You also need to hold the tp at or near the door from high up also incase the air is pulled in the door down low, and exhausts the room up high.

 

I'm going to try to run this test whenever I have a day off.

I do know, when the door is slight open and the AC kicks on, the draw from the return closes the door. I still believe that the AC only gets to cool about 50% of the room. Also the fact that my window faces the west, the room get's pretty warm on that side during the late afternoon/early evening. My nearest return is about 35ft from this room so it can't draw all that warm air out of my room without drawing the cool air first. Just my opinion.

I'll run a test this weekend and post the results.

 

Just a quick idea.

Try reversing the ceiling fan to pull the air up. It's not the "correct" way, but it may provide better air distribution to the hot side of the room.

 

I guess that an average window can let in like 5000 btu's of heat which is like canceling out a 5000 btu window air conditioner in that room! You need at least some kind of good reflector coating or shade or both on that window. (Awnings work too, but be goofy on just one window, especially an upstairs.)

But the return air behavior and how it closes the door shut is interesting. Yet it sounds logical. But my test room did not do that even though my return sucks like a vacuum only 10 feet outside the door!

I am pretty intrigued by this and want to find some other rentals that have central returns, and see what goes on around the doors in some room. Obviously it sure does seem like the cool is just being sucked right back out before it can get back deep into the room.

You say your return is 35 feet away? - and your door pulls shut?

Where is this return located exactly?

Do you have a closed door at the bottom of the stairs?

With other rooms upstairs with registers - are these doors being kept closed?

Do any other of these rooms act the same way, that if you partially close any of their doors, that they too will be drawn closed? Can you try that test for us? And, if they do, how is cooling distribution in THESE rooms? And where are THEIR registers located in relation to the door?

Do you have a gap under each door, or does each door ride right on top of carpet?

 

Sure would like to know the answer to this mystery. Hint, hint!

So interested that I conducted more tests with the handler blower going this morning, and pondering. I actually get toilet paper to pull back into the far depth of the room in the area of the pillow on the bed, which sure is a good thing, rather than have the register air all get sucked out the room. Yes, the tp does draw outward some, heading out the door, but as just stated, the tp also draws back deeper into the room.

If low pressure is created in a room to draw the air OUT and enough to shut the door, then one can only hope that this low pressure then actually can draw air back in from where you may not notice it - maybe high up or down low along the door.

I am most curious about other rooms up there, and about the doors, door clearance off the floor/carpet, where the cold air return is exactly and in relation to other rooms/hall/stairs, how big is it, how powerful it draws in air, if the intent of the return was to also capture return air from first floor(you would not think so, but never hurts to ask), but the first floor is closed off (with a door?) from reaching it, causing more suction from upstairs than what was really planned.

Or if the rooms upstairs with registers is not allowing the positive pressure from their registers out their (closed?) doors, so then what you are left with is a large cold air return with only 2 smaller blower air registers (in your hot room) that are being drawn too quickly back into the (too powerful for upstairs only)cold air return.

Also, I'd like to know how hot is is upstairs in the hall area where the cold air return is, as compared with the hot bedroom, and also what temps the other bedrooms have.

If this was my situation going on, I'd have to solve it or I'd go out of my mind from not figuring it out.

 

Register to see if I can get some help in fixing a similar problem. 2 story house (built 2005) with one room slightly above garage with 2 windows facing west. This particular room gets quite warm and never seem to get cool or cold anytime the temp is above 90s. So far I can tell it has a 6in duct. The return is about 10 ft away. The ac vent is about 4 to 5 ft from the door close to the wall next to the hall.

Things I have tried or will be trying. We have put in drapery with blackout cloth, but it doesn't seem to help. Next we are planning to put in solar screen to help block the heat from coming in.

As for the vent inside the room, the builder put in one of those that vent side to side. So one side head to the door and the other toward one window, and we really don't fee anything heading toward the middle or other side of the room. Went to HD and replace it with one that had 3 section, where bigger middle section blows foward toward middle of room and 2 small section to left and right. At least now we can feel a little air when standing in the room. To make thing worst, compared to the other room, we don't feel much air out of this vent. Over in the master bedroom, the vents there actually blow away paper if close to the vent.

So far I have learned from this thread is there's probably sizing problem for this room and getting a bigger duct from the main might help.

I have subscribe to this so I am very interested in getting this fixed as it's my little 9mo old's room and he can't sleep in their whenever the temp is in the 90s. Will try to update with some pictures.

 

How does the temperature out in the hall compare with your hotter room? (I said more but erased it til I see your answer).

 

The temp in the hall are about the same as most of the other room, very comfy. Most like due to the returner plus a big vent that's next to stairs. My other guess is also due to the 2 bedroom letting out some of it's ac as well. Beside the room I mention, the room next to it is also configure similar as the vent is pretty close to the door. There is a small hall between the 2 room leading to the shared restroom. This room isn't a problem as it's sandwich between the problem room and another room.

BTW, the house is about 3900 sq with 2 zone, one upstairs and one downstair. Upstair thermastat location is like any modern home, it's in the master.

This weekend, I will be working on trying to get some solar screen made from HD to hopefully eliminate some of the heat.

 

You'd think then that some of that cooler air would get drawn into the problem room. But, if there is that heat coming in, as you mentioned, that woud nullify any gain.

Have you experimented with shutting down say a couple registers in cooler rooms to to see if you can increase regsiter velocity in the problem room?

 

I doubt there's going to be any cold air from the hall getting into the room with the return close by. I still need to give the toilet paper test a try to see how things are flowing.

I have actually tried that without much success to that room. Overall, the airflow increase alot after I shutoff one of the vent to the master (which has two). I saw most of the gain receipt by the game room across the hall, which has either an 8 or 10in duct. In the long run, we are most like going to leave that vent close so the rest of the 2nd fl gets more air. Not sure about the effect of leaving it close as I have heard that it actually make the ac unit work harder.