About John A. White III Expertise Heating Ventilating air conditioning design construction and troubleshooting, construction management, computer hardware information, installation, troubleshooting, baseball hitting fielding pitching, investment information and ideas
Experience have worked 10 years in the mechanical construction industry designing systems, project management etc. avid computer builder, baseball player
Question We have an approximately 1500 sq. ft. house with a split bedroom design (2nd and 3rd brs are at end farthest from our electric AC unit which is in the attic) Our unit is the same size as other homes in this subdivision, and it cools all the house nicely except for those 2 bedrooms. They each have a duct which is spliced off the main duct. In summer they are hot and in winter (gas heating unit) they are cold. We have been advised by two AC contractors that increasing the size of the ducts (all in the ceiling as we are on a slab) to those 2 brs will increase air flow to those bedrooms. Closing registers in other parts of the house doesn't help. Do you think changing the size from say a 6in to 8 or 9 (a duct damper was also suggested) will help the problem? A booster fan, I am told, could work in summer but may cool the air too much in winter. We would certainly appreciate your input on this matter.
Thank you,
Laurel Rold
Answer Increasing the duct size will help some but you should also increase the register size or add another register to the room and make sure that you provide for some way to return the air to the unit either through a return duct with register or undercut the door etc. It is important to get a good quantity of air but it is almost as important that the air has somewhere to go once in the room. Adding dampers to all of the ducts will help balance the system out. Adding a booster fan will also help for both winter and summer. it won't cool the air especially if the fan motor is in the airstream what it could do is increase the velocity of the air which if it blows on people will seem cooler. I would also make sure that all of the ductwork in the attit is insulated with at least 1" fiberglass duct wrap. the hot air in the attic in the summer and the cold in the winter could be cooling or heating the air as it travels through the ductwork if it is not insulated. If this were my house I would add another register to each room with a seperate or larger duct run and make sure the air will return out of the room and make sure the duct is insulated.
