Why is my kid's room the warmest in the house & what can I do about it?
June 9, 2015 12:40 PM   Subscribe

I live in a 130-year-old house modernized with air conditioning that works reasonably well keeping the house a decent temperature through the summer. However, my kid's room gets warmer than any other room in the house.

It seems to have the same size vent, roughly in the same place as our other bedrooms, but it's routinely 5 degrees warmer than the other similar bedrooms. I assume it's more at the end of the ducts, and the a/c is running out of pressure or something, though I can feel air coming out.

Is there anything I can do? Obviously, I can switch my kid's room to another one, but that's not ideal for other reasons. I tried closing the vents in the less used rooms, but it didn't do much. I take the vent cover off, leaving it fully open, but it doesn't help a lot. I may insulate the attic, though that's pricier than I expected. I'm dreading getting a window unit just for this room (and getting a separate a/c for the second floor is crazily expensive), but it also feels stupid to do nothing.
posted by davebug to Home & Garden (18 answers total) 2 users marked this as a favorite
 
Does it get more afternoon sun than other rooms? That would explain it. Insulated curtains would help.

Or maybe is it over the garage? Garages aren't generally temp-controlled so having warmer air underneath would cause it to be hotter, and maybe insulating under the floor would help.
posted by rabbitrabbit at 12:45 PM on June 9, 2015


Does that room face south or west, or otherwise get more sun exposure? If so, you could try, for example, planting a tree or two between the outside wall and the sun. You could also try building a covered porch or other overhanging structure there to shield the window and walls from the sun.
posted by amtho at 12:45 PM on June 9, 2015


Speaking only to solutions to lower the temperature of the room, not anything that might be going on with your AC system:

1. Oscillating fan, oscillating fan, oscillating fan. It will cost like $15 and lower the temperature of the room instantly. I leave mine running 24 hours a day -- it's literal pennies on your energy bill.
2. Heavy curtains drawn during the day to block sunlight.
posted by kate blank at 12:47 PM on June 9, 2015 [1 favorite]


What goes in must come out...Is there a return vent in that room? If not then the room may be over pressurized, especially if the door is closed, and there's just no where for the cold air to flow.

Or: the system is improperly balanced, and even though you feel some cold air there just isn't enough. Yes, you said you have closed off other vents, but you may not have hit the right balance. Vents closer to the system may need to be tuned way down for example, and then there's leakage. You need an experienced HVAC tech with a whole slew of test equipment, leak testers etc.
posted by Gungho at 12:58 PM on June 9, 2015 [1 favorite]


Is the damper all of the way open? Does the velocity of the air coming out of the vent seem to be less than in other rooms? Perhaps the duct is restricted. Also, try partially closing dampers in the other rooms nearby to see if the amount of cooling in this room increases.

Our kids' room was warmer than the rest of the house. I believe that the kids themselves generated excess heat.
posted by Midnight Skulker at 12:59 PM on June 9, 2015


Maybe there's something relatively easily fixable wrong with that stretch of duct - squashed if you have the squishy kind, torn, partially disconnected...
posted by pennypiper at 1:09 PM on June 9, 2015


If it's truly just a problem with not enough air power, you could always try one of these. But it's likely something else. A wall or the ceiling could be missing insulation somewhere. You can download an app for iPhones that lets you measure heat.
posted by resurrexit at 1:13 PM on June 9, 2015


There are also register boosting fans that replace your vent cover, instead of having to tear up ductwork.
posted by Behemoth at 1:16 PM on June 9, 2015 [3 favorites]


If your house is 130 years old, I would guess the insulation is uneven and this room is not insulated in the same manner as the rest of the house. Is this part above an old or nearly original kitchen addition? Is this bedroom away from the others or over or under different structures? Or is there no attic (and no insulation) over this room?
posted by littlewater at 1:17 PM on June 9, 2015 [1 favorite]


Our kids' room was warmer than the rest of the house. I believe that the kids themselves generated excess heat.

Mine sure does. Got curious about that and started taking measurements. His room would register at 65 when the rest of the house was 50. It didn't matter which room. I have no idea how a 60 lb person does that to a large room.
posted by Mr. Yuck at 1:20 PM on June 9, 2015


What kate blank said. My bedrooms (in a typically English home, with no air conditioning) have the sun on them all day. I installed wooden slat blinds in my bedroom, I keep them closed on hot days, and run a fan. My fan is 45W, so very low consumption.

You can buy a fairly cheap fan in any homeware store - as it's for a bedroom, look for one that doesn't have LED lights (or maybe it's just me who's over-sensitive to LEDs in a dark bedroom) - so the cheaper end of the spectrum.

I used to have a tower fan, which burned out after a few years. It was excellent, but it took up floor space I couldn't spare in a small bedroom. I replaced it with this one, which sits nicely on a dresser and which provides an awesome amount of cooling. The white noise is great for sleep too.
posted by essexjan at 1:36 PM on June 9, 2015


Is there a return vent in that room? If not then the room may be over pressurized, especially if the door is closed, and there's just no where for the cold air to flow.

This was my first thought. Our kid's room was consistently colder in the winter and warmer in the summer than other rooms in the house, and the culprit was a bookshelf in front of the return vent that was partially obstructing airflow. I hadn't even realized the bookshelf was blocking the vent, because there was like an inch of clearance and that seemed like plenty to me, but the temperature difference moderated once we moved furniture so there was nothing in front of the return vent. Might be worth a try.
posted by iminurmefi at 1:44 PM on June 9, 2015


1. Oscillating fan, oscillating fan, oscillating fan. It will cost like $15 and lower the temperature of the room instantly. I leave mine running 24 hours a day -- it's literal pennies on your energy bill.

Fans by themselves do not lower actual temperatures. They lower perceived temperature. They can in fact raise the temperature because of the fan motor. The only time they will lower temperature is if they can move air from a cold zone to warm zone.
posted by srboisvert at 2:28 PM on June 9, 2015 [5 favorites]


Have you actually checked the ductwork (had it checked by a professional)? The ducts in my parents house got like... partially uncoupled or something in part of the house, and while it still seemed like they were working, there was a lot of air being lost along the ducts.
posted by brainmouse at 2:46 PM on June 9, 2015 [1 favorite]


I live in a 115 year old house with a central air system and it's great but always WARM in the bedroom which is the furthest room from the outdoor air exchange unit/HVAC. I can be wearing a sweatshirt in any other room but that room (it's my one guilty pleasure to crank the air). I bought an inexpensive, table-top, energy efficient fan and just keep it running in low. It ends up causing a $1 increase in billing each month and just keeps air flowing. Additionally, keeping blinds in that room closed during the day helps dramatically. I usually keep all blinds closed during hot days anyways.

When temperatures are 75 and under I shut the air off, put in a window fan in that room and generally close all blinds to the point where the window is open and close the blinds - instant cool.
posted by floweredfish at 3:18 PM on June 9, 2015


Are they running a computer a lot? (My bedroom is always quite warmer than the rest of the house due to this.)
posted by sperose at 5:22 PM on June 9, 2015


Why? It's a combination of a lot of things. Heat rises and his room is upstairs. Retrofitted central AC often doesn't have great ducts, having instead the ducts that fit. Longer duct runs may have lower air pressure (they're not supposed to, necessarily, but see previous comment about retrofitted systems). His room may get more sun if it faces south or west. Also if your house is like our 90-year-old house, his room may be in what was originally an uninsulated sleeping porch. Our sleeping porch was enclosed, but it wasn't insulated. Also our roof slopes in such a way there's crawl space over the front bedroom, and a low ceiling in the back. That could make it worse.

Without additional fans at the base of each stairway, our house has a summer temperature gradient of 12° F from the basement to the upstairs bedrooms. With additional fans and judicious use of the central fan, that gradient can be as little as 6° F, or as much as 8. It's hot upstairs, is what I'm saying. If you can install one, a ceiling fan is less obnoxious than an oscillating fan (and more effective at maintaining comfort). Add insulation. Leave his door open.

And if none of that does the trick, get a window unit so the central AC doesn't have to over-cool the rest of the house to keep his room comfortable.
posted by fedward at 7:08 PM on June 9, 2015


Come the fall/winter, you can likely ask your local energy utility to perform a heat loss inspection. Would be valuable for understanding any insulation or other causes.
posted by JackBurden at 7:19 PM on June 9, 2015


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