Warm in one room with A/C on and set at 75?

New house [6 months old] and have a bedroom [used as an office] with bay windows. Sun hits these windows most of day until about 4 pm. Tried adding another vent, dark full screens and added two roof ventes on room...A/C set at 75 but this room always [night and day] around 79/80...... Builder also checked for insulation in walls and there is some.....Only way to keep this room cool is to set A/C at 72 but unit runs all day.......








Anyone has an answer ???????????????

Warm in one room with A/C on and set at 75?
well your on the right rabbit. your bay windows are the likely culprit.





get a hold of a commercial glass out fit and get a uv reflective film installed on the glass. you have seen this stuff on big buildings with a lot of glass, it has kind of a blue green iridescent color. its kindly costly, but it helps. i had to have some windows coated in a big office building coated once, there was no way we could keep up with the heat load generated by the glass in the building. after the coating the rooms cooled much better.





have a hvac guy check to make sure the extra branch lines going into the room are coming off the main trunk.





you can increase the airflow into the room by adding a return air grill on the top of the door(unless the room has its own return)





you can try shutting down the vents in the rest of the house a little at a time to better balance the system.





if this still isn't helping, have the take offs replaced with scooped takeoffs.....take offs are where the branch line joins the main trunk.....if the take off is too close to a bend or transition, it will be starved for air, so a scooped takeoff is needed.





as a last, and i mean very last resort, you can add a booster fan to the branches that feed that room. they are usually noisy, and i havent seen very many that have been installed right.





all my best,


Possum,hvac guy
Reply:Return air is very important for proper cooling it is allot more efficient removing the hot air and replacing it with cool air rather than just dumping cold air in a hot room.Check to see if there is a return air vent in the room if so you can check it for air flow with smoke from a cigarette or freshly extinguished candle. If there is little or no air being removed then the return air duct work may not have been designed or installed properly and should be checked, if there isn't any return air then one should be added. If the room is on the second floor then return air is extremely important . but just remember with all homes old and new , hot air rises and you get a couple degrees difference per floor. to minimize the cold air from flowing to the lower levels and hot air rising you should


1-circulate fan all the time by putting fan switch in the on position at thermostat


2-Keep doors closed to each floor of the home including the basement if possible


3- keep door to the problem area closed as much as possible.
Reply:You can have a vent fan added to the vent only into this room. This will put more air into the hot room. You can have a switch directly tied into the a/c and also have an on/off switch installed into the wall.


I'm surprised your contractor didn't suggest this.





An easier method is to put up curtains.
Reply:Awning? Plant a deciduous tree or two? Try to intercept the sun before it hits that part of the house.





I say deciduous tree so that during the winter the sun will shine through the naked branches and help to warm the house when you need it.