Vaulted Ceiling created air flow issue

9 years ago

We recently opened and vaulted the entire ceiling of our main room which includes living room, dining room and kitchen. Everyday @ 2pm the sun beams right through and this room gets really hot even though the AC is on 68. The vents are on the floor. We are leaking Freon so we know this is part of problem and we want to replace the unit. So we do not know if we just replace the current unit as is or some people said we should put the AC on its own zone in the attic (AC was added to the heating at some point). Even replacing the unit might not solve the airflow issue in this main room so some people said we should consider a fujitsu unit or could a fan work?

Featured Answer

kenjwy

9 years ago

last modified: 9 years ago

On the down side creating the vaulted ceiling increased the cubic footage of space you are cooling, which might be significant depending on how big a percentage this is of your total space. It also may have made your house less efficient by eliminating the insulating effect of the closed-in space you opened, perhaps an attic.

On the plus side a vaulted ceiling can help with cooling because the warmest air rises over your head where you do not feel it. The room can feel chilly in winter for the same reason.

A ceiling fan would likely raise the temperature of the air you feel because it will stir the air up so you lose the advantage of the vaulted ceiling for cooling. (The warmest air won't be over your head anymore.) Of course any fan can promote greater comfort by keeping the air moving, but in this room I'd put it on or near the floor. By the Fujitsu unit I assume you are referring to a mini-split. They'll keep you cool for certain but they're costly, and I would not be putting money into a whole new system until you have the problem with your main system addressed. When that system's working right you can see where you are and make some decisions.

Also consider blinds for the windows letting in all of that sun. Something you can open all the way up for the view when the sun isn't coming in, but close to keep the room cool when the sun shines from that direction.

Sort by:Oldest

Comments (6)

mike_home
9 years ago
What is probably happening is the cold air produced by the floor vents is not able to cool the air at the top of the vaulted ceiling. This is because cold air is denser than warm air. You are going to have to install supply vents near the top of the vaulted ceiling. You should also install a return at the top so warm air can be pulled out of the space. The supply and exhaust vents should be placed on opposite sides of the room.

A fan can help mix the warm and cool air masses. I would think the fan blowing air on you would make it feel cooler due to the wind chill affect. In the winter you can reverse the fan so that you won't feel cool air blowing on you.

The other strategy is to lower the heat load of the room. How much insulation is installed in the attic above the vaulted ceiling? Depending where you live you want at least R30, and ideally at least R40 insulation value. Closing blinds when the sun is out will help. You could also apply a reflective film to the window glass to help reflect the sun's rays. You may like that look instead of closing blinds and drapes.
Jason Goldberg thanked mike_home
Related Professionals
Fayetteville General Contractors · Orange County General Contractors · Kennewick General Contractors · Shreveport Home Remodeling · Baltimore Home Remodeling · Amherst Home Remodeling · Marinette Home Remodeling · Stockton Home Remodeling · Edmonton Home Remodeling · Carbondale Bathroom Remodelers · Middlesboro Bathroom Remodelers · Abilene Bathroom Remodelers · Jamestown Bathroom Remodelers · Williamsport Bathroom Remodelers · Riverside Bathroom Remodelers
Jason Goldberg
Original Author
9 years ago
@mike_home there is insulation throughout the entire vault. Not sure which type. We do not have shades yet and plan on buying 3% solar shades . So you are saying we will benefit more with the supply being at the top then where they are on the floor right now.
mike_home
9 years ago
If you could supply cold air near the top, then it will naturally "fall down" towards the fall. This should create some convection air currents.

If you are going to buy new HVAC equipment then find someone who will do a load calculation. Vaulted ceiling are very nice but unfortunately they present heating and cooling challenges.
klem1
9 years ago
"but unfortunately they present heating and cooling challenges."

That is true so make certain anyone you hire understand's how to address said challenges.
PRO
Austin Air Companie
9 years ago
last modified: 9 years ago
Vaulted ceilings tend to trap heat at the top, but placing a return vent is typically not pleasing aesthetically... same thing with supply vents.

So you have your work cut out for you.

A lot of people do not like to be able to see beyond the grill. Due to the angle of the vaulted ceiling this is very challenging.

Vaulted ceilings are a statement... that statement gets clouded is about the best way I can describe it.

Another option would be to place a ceiling fan in the center of this room and reverse the fan to blow upwards. This will pull air off the floor and push air up to the vaulted ceiling which creates a cascade effect. Depending on the room size you would want a ceiling fan with a wide wing span so you don't have to run it on high speed for it move a generous amount of air.

The idea is to just keep hot air from getting trapped in the vault of the ceiling and pull up the cooler air off the floor. This is aesthetically pleasing as well.