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Bonus room above garage hotter then rest of upstairs

post #1 of 26
7/18/10 at 5:41pm
Thread Starter 
I have a new house built in 2007. Im using the bonus room above my garage as my dedicated HT.

It gets alot hotter then the rest of the house in this AZ summer heat.


I have crawl space access in the garage but i havent checked if its insulated between floors. Is it common practice to insulate the garage ceiling if a room is above it when a new hose is built?

I either have no insulation there or not enough, would adding the maximum amount of blown cellulose make a differene in this bonus room?

The garage is actually a 3 car garage with a 2 car garage door but 1 side is tandum(double length) making is a 3 car garage, The back half of the tandum is directly below the bonus room. The rest of the garage has nothing but a roof above it.


The bonus room also has 3 vents and 1 return in it but its still get alot hotter then the rest of the house. The garage must be in the 120's right now at least since the outside temps have gotten that high.

So bottom line will adding maximum about of blown insulation solve my problem?
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post #2 of 26
7/18/10 at 6:05pm
Maybe. I would invest in a cheap handheld no touch infrared thermometer and take readings off all the walls and the floor (roll back the carpet) in the bonus room and see which surface is hotter than the room. That might point direction of what to work on first. I would also increase the supply to the room with booster fans that you can turn on when you use the room.
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post #3 of 26
7/18/10 at 6:44pm
Thread Starter 
Good idea i will have to look for one of those next time im out.

I did walk around the room and feel with my hand,everything seems "cool" except the window area. But i didnt pull up the carpet just felt it in different spots and differnet walls, the exterier wall "feel" the same as the interier wall.

i have 1 large, 2 medium and 2 small windows in the room, all 5 have 90% sunscreens. All of them also have 1/8in hardboard nailed into the seals to block light and all but the large one have blackout curtians, the large window does not have a curtian becuase the screen will be blocking it.

Just by touch my biggest heat gain i can feel are the windows,not sure what else i can do to them aside from adding blinds or tint. Would adding alluminum foil on the back of the hardboard reflect the heat enough to make a difference? It wouldnt be visible from outside becuase of the sunscreen so i shouldnt have a problem with my hoa.
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post #4 of 26
7/18/10 at 6:55pm
Many times, these rooms have a vaulted ceiling. These ceilings are thinner and there is less room for insulation than the rest of the house. My HVAC guy said that this caused heat to transition from outside to inside easier.

Also, the ceiling in the garage is not usually well insulated and sealed with a tight vapor barrier. I wish builders would use spray foam in these applications.
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post #5 of 26
7/19/10 at 2:58am
The other issue, often overlooked by contractors trying to save a buck, is bonus rooms are typically the most exposed rooms in a home. In most cases, you have three sides and the roof/ceiling exposed to the outside. In addition, the garage is not a heated/air conditioned space leaving you with the only space in the house with 5 of 6 surfaces exposed to unconditioned space.
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post #6 of 26
7/19/10 at 5:33am
I have this situation: bonus room with less than 1 side attached to the house. I only have a 3' wide hallway connecting it to the 2nd floor of the house. Also, since I added my garage and bonus room after the house was built, I have no return line for the heat pump. I only have 1 supply line that is the longest run in the house. So needless to say, it can get hot (in summer). I have a temporary solution and a permanent solution to this.

Temporary: when we plan to watch movies I open the door and supply line vent way ahead of time and put a box fan in the doorway. It essentially does what bigmouth described by putting extra fans in the supply ducts. It exchanges the air in the room very quickly. That makes it decently comfortable when it is blazing hot outside.

Permanent: I'm starting the early planning stages of moving my theater into the basement.
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post #7 of 26
7/19/10 at 5:53am
I have the same situation over a 3 car garage with vaulted ceilings: hottest room in the house : the electronics adds to the heat load

Building codes usually require heavier sheet rock in the garage ceiling for fire protection and so no fumes from cars can enter living space above: but mine has no insulation [floor is carpeted ] I doubt insulation below the floor would help: most of the heat comes from the vaulted ceiling/ windows/ electronics

The only solution that worked for me was to add a Sanyo ductless air conditioner to augment the built in AC which was marginal
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post #8 of 26
7/19/10 at 5:54am
I have a bonus room in a similar configuration in my house. There is insulation between the garage celling and the floor of the bonus room. Also, my builder used an OSB product called Tec-Shield for the roof sheathing over the bonus room (I actually had them do the entire roof with it). It has a radiant barrier on the underside of the OSB that helps to reflect the heat away from the roof.
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post #9 of 26
7/19/10 at 7:06am
$30 Infrared thermometer.

http://www.harborfreight.com/non-con...ter-96451.html

On the warm windows, The windows I blocked are covered with plywood, insulation, drywall and 1 inch of linacoustic. They don't get direct sunlight.
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post #10 of 26
7/19/10 at 10:16am
I think you're missing the elephant in the room. OK, I meant GARAGE. Since having had my garage doors replaced with 2" steel insulated doors and the weather seals around it replaced, I've noticed a HUGE difference in the temperature of the garage. Granted, I'm not in Arizona, but we've had SEVERAL days pf 95+ in a row and several more of 100+ (and HIGH humidiity) here in Northern Virginia.

You might check how your cathedral ceiling is built. Mine has full 2X10s just like the rest of the roof and there is plenty of rrom to get full insulation in there.
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post #11 of 26
7/19/10 at 10:35am
Thread Starter 
Thanks for all the tips guys

Also my bonus room has just a regular flat ceiling. The master bedroom a couple rooms over has vaulted but it doesnt have the cooling problem.

About insulating my garage door,i am thinking about that to keep the garage cooler but 1 concern, there is a vent in the garage towards the ceiling wouldnt that just let the hot air in anyways if i sealed the garage door good?
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post #12 of 26
7/19/10 at 10:58am
In addition to the fact that your room over the garage does not benefit from having an air conditioned room below it (or a nice cool hunk of earth under it) people tend to pull their cars into the garage at the end of the day. Now you have a couple hundred pounds of steel in the engine, a couple gallons of radiator fluid in the radiator, plus the condenser is all warm from running the AC in the car, etc. etc. All that is now sitting under the house at 180°F or more, just heating up the garage as it all cools down...

One thing that can be easy and useful, depending on the ambient conditions, is to just leave your garage doors open as long as possible after coming home to allow the heat from the vehicles to blow out as much as possible while they cool down. It's not going to fix your problem, but it can help reduce the problem.

-Suntan
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post #13 of 26
7/19/10 at 11:06am
Quote:
Originally Posted by abshard View Post

About insulating my garage door,i am thinking about that to keep the garage cooler but 1 concern, there is a vent in the garage towards the ceiling wouldnt that just let the hot air in anyways if i sealed the garage door good?

Are the walls of your garage insulated? If they are not, insulating the door may not provide much usefulness.

Is the garage door facing South or West? If it is, then insulating the garage door may provide some useful effect. More so from the solar load than from any convective heat transfer from the outside air.

As for the vent in your garage, negligible heat is coming down into the garage from that opening compared to the heat coming in through the walls and a loose fitting garage door that is just a thin slice of metal. Regardless, you really shouldn't plug up the venting in your garage. It is good to have adequate venting in the garage, assuming you drive your cars in/out of there, even if it makes it a little warmer in there.

In any case, if the goal is to keep the room cooler, you'll have better return on your investment to insulate the floor/ceiling between the room and the garage heavily, than you will in insulating the entire garage.

-Suntan
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post #14 of 26
7/19/10 at 11:22am
Thread Starter 
Regaring leaving the garage door open when i arrive,currently its 110-120 during the day and it cools off to a nice 100 at night outside

Im not sure if the garage is insulated, most likely not unless it was require by code i know i didnt pay for and upgrade to insulate thje garage but i did pay for extra insulation in the rest of the house along with 2x6 construction.

i just need to go climb up in that crawl space above the garage and look if its insulated at all or if there is room for more,its just so dam hot in there.

One more concern after i insulate the celing of the garage (or add more) there will still be a gap between the garage ceiling with insulation and the floor of the bonus room correct? Which will most likely stay very hot? Would it be better to use fiberglass batts in the upper part of the crawl space instead of blown cellulose on the bottom or do both?
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post #15 of 26
7/19/10 at 11:24am
I have the same issue with my AZ Master Bedroom right now. AC and ceiling fan runs all night to keep the room at 80 degrees. At 5 am this morning my car's thermometer in the garage below read 102.

My media room is a converted 2-car garage on the other side of the house. Heat is still an issue from Jun - Aug, but I've done better by putting barrier insulation in the attic. Used to be 95 -100 in there late afternoon, now it's more like 85. I get some AC from tapping into the first floor main unit and use a Friederich mini-split 12K BTU to get the room down to 78 or so. I put fans and AC on 2 hours before entering room in the evening and it's good to go.

Hope that helps.

Max
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post #16 of 26
7/19/10 at 12:15pm
One other point, along with the other good suggestions, is that sometimes builders do not put the same amount of ridge vents or attic vents over the bonus spaces. In our current neighborhood, one builder did just that, and most of those homeowners added attic fans, additional ridge vents, or some combination to get proper air flow in that space.
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post #17 of 26
7/19/10 at 12:43pm
My neighbors garage had an afternoon sun heating problem. It would get much hotter than outside so he popped a couple of window fans in the windows, One blowing in one blowing out, both on thermostats.
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post #18 of 26
7/19/10 at 12:57pm
Quote:
Originally Posted by abshard View Post

Regaring leaving the garage door open when i arrive,currently its 110-120 during the day and it cools off to a nice 100 at night outside

As I said, depending on your conditions. That said, your car will have a significant percent of its components a good 80° to 100°F *higher* than your 100°F ambient temps when you first shut off the key. If your garage is already at a very high temp when you get home, shutting all that up in your hot garage is not going to make it any cooler.

In any case, you'll get little sympathy from me, let's just talk in 6 months when my ambient temps are climbing all the way up to -15°F for the daytime high...

-Suntan
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post #19 of 26
7/19/10 at 1:03pm
I also have 2 window fans running in the garage but it does little good: the boilers are in the garage too

To the good: in the winter I rarely have to run the heat in my HT above the garage
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post #20 of 26
7/20/10 at 7:16am
I was given an idea by a HD guy yesterday. He said to leave the garage door up 8-10" or so, enough to create a vent out, but not for others to get in. Then use a swamp cooler at the opposite end of the garage to cool and push air out of the garage.

The only caution he said was using a s.c. in an A/C'd room. Swamp coolers add moisture to the air, while A/C's remove it. So you'd have a fight between the two, which he said the A/C unit would lose and burn out first. Also, he suggested getting a s.c. rated for twice the size of the room as the ratings tend be generous.

Don't know if it would work, but worth consideration.
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post #21 of 26
7/20/10 at 7:31am
Quote:
Originally Posted by Dennis Erskine View Post

The other issue, often overlooked by contractors trying to save a buck, is bonus rooms are typically the most exposed rooms in a home. In most cases, you have three sides and the roof/ceiling exposed to the outside. In addition, the garage is not a heated/air conditioned space leaving you with the only space in the house with 5 of 6 surfaces exposed to unconditioned space.

This is so true. I also learned that my entire 2nd floor wasn't cooling as well as the 1st floor, and after multiple HVAC rep visits and many passing years discovered the A-coils and compressors were installed backwards.

This meant the 1st floor was easily cooled by what was an over-sized zone system and the 2nd floor was under-sized and never being fully cooled in the summer. The air handlers, on the other hand, and the furnaces were correct.

After killing the 2nd floor under-sized system, I replaced it with some slightly over-sized (by a half ton), had two extra source vents installed (one in the Mini Me HT room (now decommissioned) and one in the computer room, and added a new return in the hall.

Now it can reach 95-97ºF outside in Atlanta Summer and those rooms stay 70-72ºF while in use. Yes, I am a Yankee (in the South) and loving my new AC. It was more than worth the correction.

If the original poster doesn't wish to replace the HVAC system then consideration of a split/ductless add-on is the best bet.
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post #22 of 26
7/20/10 at 7:32am
Oops, I should have stated the now decommissioned Mini Me HT room was over the garage, and always not as cool as I'd like it and used with a CRT projector. Can we say heat problems? LOL
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post #23 of 26
7/20/10 at 7:37am
Anyone suggest calling an HVAC company / expert? Tell them what you expect in terms of outcome of project, get a quote, have a couple others bid it, complete the job, enjoy the theater...

Not really a problem at all!
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post #24 of 26
7/20/10 at 10:00am
Is your hot water heater in the garage? If so, replace it with a heat pump for hot water. This effectively air conditions the space when it runs; it's made a huge difference in the temperature of my garage.

That said, my bonus room is over the garage (and is also my theater) and I don't seem to have any heat problems (I'm in S. FL), so a lot of it must be dependent on the HVAC configuration.

Also, I covered all the windows in my media room with "EZ Window Covers". They are totally light blocking, and they are white on the outside; that seemed to bring the temperature down further (even more than that heat pump hot water) for almost no cost. I assume that you've already covered the windows; but make sure that whatever you're using is very heat reflective (white, in my case). That's a really inexpensive fix, if you haven't already done it.
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post #25 of 26
7/20/10 at 11:45am
Or go tankless
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post #26 of 26
7/20/10 at 12:51pm
Quote:
Originally Posted by BIGmouthinDC View Post

Or go tankless

Tankless will probably reduce the temp a bit (no 50G tank of 150 degree water sitting there), but doesn't have the AC effect of a heat pump. If cooling the space is a secondary concern (secondary to having hot water) heat pump is the way to go. If "hot water forever" and increased efficiency (over an electric/gas tank) is the primary concern, tankless is the way to go. And, of course, tankless is silent; heat pump is not.

In FL, the heat pump for HW is a real natural fit, the water isn't that cold anyway, and.. Well.. There's PLENTY of heat!
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