Best approach in general to a hot upstairs?

[SecondCor521]

My house is mostly one level but has a bonus room over the garage. The garage is uninsulated with drywall. The bonus room and the garage both face west and get the afternoon sun. The bonus room and attic are well insulated, and the west-facing window in the bonus room has that reflective window film professionally applied.

Still, the bonus room runs about 5 to 10 degrees hotter than the downstairs. I live on the downstairs and my son lives in the bonus room, which makes it hard to agree on a temperature for the thermostat. Comfortable for him is cold for me, comfortable for me is hot for him.

Options I'm considering:

1. Ductless mini-split. I know these work well and are expensive.
2. Roof ridge vent. Not very expensive, seems like it would help.
3. Dual zone AC. Existing single zone HVAC is in the garage.
4. Attic fan with a thermostat. Attic has vents on the north, south, and west facing sides.
5. Increased roof vents. Attic already has the appropriate number of roof vents, but maybe more would help.

The roof shingles are regular three tab asphalt shingles. Roof is original to the 2004 home. Tentative plan is to replace the roof shingles in the next few years.

Thanks for any input / thoughts / opinions.

 

[Sunset]

commonly the room above the garage has a poorly insulated floor, heat could be coming in from the hot garage.
Putting a venting fan in the garage to blow out the hot air would reduce a source of heat. Only need run it in hot weather, not in Winter.

 

[braumeister]

We had an attic fan in a house years ago and I was really surprised at how effective it was. I recommend it.

 

[Chuckanut]

I would think some type of whole-house fan for the room above the garage might be a big help on all but the hottest days. If there are too many of the very hot days, a simple window AC might work and be more cost effective than a mini-split. If heat is also needed, then the mini split might be a winner in terms of comfort.

 

[TwoBitsCA]

I have a similar situation...I'm thinking a whole-house type fan that would suck the warm air out of the bonus room and into the attic would work. If the door to the bonus room was open, the cooler air in the rest of the house would get sucked into the bonus room in theory.

 

[MichaelB]

You probably have the opposite problem in winter, with the room over the garage warmer than the rest of the house.

The split will work but it’s an expensive option. An attic fan should help a great deal, a window fan in the room above the garage wall also help. More and better insulation should also help some. All 3 combined should help and cost less than the split and much less than a dual zone.

 

[NgineER]

Venting would be good, as sunset points out, floor/ceiling insulation might be lacking between the garage and the bonus room. You might be better off adding a mechanical fan to one of the vents rather than installing a new ridge vent before you have to replace the whole roof.
I assume insulation between bonus room and garage would be hard to access, but pulling down drywall and installing new plus fire taping is probably not that expensive.

Sealing and insulating the ductwork leading to and from the bonus room would likely help too.

You might be able to put baffles in the ductwork from your furnace to direct more airflow to the bonus room vs. your space.

Just some thoughts on how to maybe improve your situation.

 

[target2019]

I put in a better ventialtion exhaust fan just after adding insulation to attic floor. That was a major improvement.

Next came the new roof and GAF gold system. That included ridge vents as well as permeable sheet sealing before the roofing tiles.

You sometimes can go in stages. In your bonus room you may find adding a smaller split will be icing on the cake.

 

[OldShooter]

Garage ceiling insulation would be the first thing I'd check. If, as you say, the bonus room is well insulated then the garage is the last frontier. A good insulation contractor should be able to check for you and offer alternatives for the ceiling and an opinion on whether insulating the garage walls would be cost-effective. He should also have an infrared imaging camera, and be able to survey the bonus room for issues.

 

[Kings over Queens]

Insulate the garage ceiling (heat rises) and introduce a second AC system. You might get away with a window unit or wall sleeve unit, but the minisplit is probably the most efficient and cost effective.

buy once cry once.

 

[GalaxyBoy]

I have the opposite situation where the basement family room stays cold in the winter because the cool air from upstairs pools in the lower level. I found that running the fan on the house HVAC system continuously kept the air mixed and closer to the same temperature. Not a long term solution for you, probably, but might help. One caveat though, my basement room has an air return.

 

[pb4uski]

I have to wonder if you applied spray foam insulation to the ceiling joist cavities of the ground floor of the garage if that might keep the bonus room much cooler. That and perhaps a window a/c unit might do the trick.

I think I would do the insulation first and then see how that works and then add the window a/c only if needed.

 

[Winemaker]

Hot Air rises, cool falls. We have a 2 story home with a basement. When the air conditioner is on, all upstairs doors are closed and cooling ducts are open to the max in the occupied rooms. Downstairs ducts are choked down. Imagine the AC treated air is like water; so you want to "fill" the upstairs room up with the cooler air and prevent it from flooding downstairs. Our house also has 2 return air vents, one above the other, and the lower vent register has a control on it. It gets closed in AC season, so the cool air can "fill" up the room and push the warmer air to the return vent near the ceiling. It really helps out.

We do the opposite once the furnace comes on.

 

[GrayHare]

A window AC will be less costly than some other options and permit him to run it only when he deems that room too hot.

 

[skyking1]

^ that is where I would go. I pick them up for free sometimes.
An active attic vent will help, but ultimately that huge shingled area will defeat passive solutions.

 

[TappyGee]

My house is mostly one level but has a bonus room over the garage. The garage is uninsulated with drywall. The bonus room and the garage both face west and get the afternoon sun. The bonus room and attic are well insulated, and the west-facing window in the bonus room has that reflective window film professionally applied.

Still, the bonus room runs about 5 to 10 degrees hotter than the downstairs. I live on the downstairs and my son lives in the bonus room, which makes it hard to agree on a temperature for the thermostat. Comfortable for him is cold for me, comfortable for me is hot for him.

Options I'm considering:

1. Ductless mini-split. I know these work well and are expensive.
2. Roof ridge vent. Not very expensive, seems like it would help.
3. Dual zone AC. Existing single zone HVAC is in the garage.
4. Attic fan with a thermostat. Attic has vents on the north, south, and west facing sides.
5. Increased roof vents. Attic already has the appropriate number of roof vents, but maybe more would help.

The roof shingles are regular three tab asphalt shingles. Roof is original to the 2004 home. Tentative plan is to replace the roof shingles in the next few years.

Thanks for any input / thoughts / opinions.

Try the register vent fans you can get for about $50 on Amazon. Some of them get great reviews.
My son is over the garage also and we went with the Midea Duo portable inverter AC because he has too much furniture blocking the vents he is not willing to part with. We are very happy with it and have not had to empty any water out of it. They are designed to not have condensate issues.

 

[jldavid47]

Try the register vent fans you can get for about $50 on Amazon. Some of them get great reviews.

+1

They will not completely equalize the temperatures, but they will improve the situation. We use Airtap vent fans and they definitely help us.

 

[rk911]

We put in a ductless mini-split in our attached 4-season sun room 7-8 years ago. Don't recall what we paid but we didn't have to swallow hard, close our eyes and, reluctantly, write a check. The mini-split keeps the room warm in winter and cool in summer.

 

[Plantman]

I would think a window air conditioner would be your best option.

 

[Texas Proud]

I see a few window units listed... I would do that over mini-split... you can get them with a remote...

One option that I did (to be fair, I have a whole upstairs almost as big as downstairs) is split the AC with dampers... If the house ducts are split correctly and one major line feeds the bottom and another feeds the top you can get dampers that open and close, add a thermostat in the room and POOF, you have a dual zone system with one AC.... it worked great...

I have now upgraded my single unit to a variable speed and the temp is what I want it to be on both floors...

 

[treeofpain]

Similar situation. The attic fan helped a bit. Finally got the mini split and wished we had done it sooner.

 

[Koolau]

I've heard of "painting" the roof "white" to reflect much more heat. I've heard it can be effective if done properly but do not know the details, so YMMV.

 

[Ronstar]

I would think some type of whole-house fan for the room above the garage might be a big help on all but the hottest days. If there are too many of the very hot days, a simple window AC might work and be more cost effective than a mini-split. If heat is also needed, then the mini split might be a winner in terms of comfort.

^^This. We had a whole house fan in our last house - 2 story with basement. I would open the basement windows, and turn on the whole house fan. That would draw cool air from the basement into the 2nd story. Worked great - even on hot days - I usually ran the whole house fan in the evenings.

 

[Jerry1]

Fans and insulation would be my first action. Then one other thing that I didn't see mentioned is to put an in line fan in the duct to that room. We had one and it helped a lot. I delivers a lot more cold air to the room. No, nothing like a mini split or window air conditioner but a noticeable difference.

Also, keep the door closed. Cold will sink so you need to capture it in the room. Again, not a miracle but it will help.

After that, pull out your wallet and do whatever. Personally, I'd prefer a mini split over a window unit, but it's all about how much you're willing to spend at that point. My main goal would be to get the most quiet option if I was bringing in a new mechanical device.

 

[jollystomper]

I would go the window or "portable" AC route. Simplest and cheapest solution to start with. We have done this in a room where DW likes it cooler than what the house is set at. Rather than chill the whole house, she can just set the window AC in the room to what she likes. Worst case, if that is not good enough, you have not spent much for starters.