Air Conditioning Question. I'm receiving very cold air on my main floor but not through the upstairs vents?

Question

I have a 5 year old house that's about 2200sq. ft. I have floor vents. I get good air flow through the floor vents in the basement and on the main level. Also getting good air in one of the bedrooms upstairs. I get very slight cooling in two additional rooms upstairs (but not air conditioning cold by any means). Lastly the biggest room upstairs (the master bedroom) which has 3 air vents is a sweat box. No air flow whatsoever. Any ideas? I changed the furnace filter, but no improvement. Please help.

Answer 1

1) if there is an attic space check to see if its cold in there.
if so your ducts may be cut or have a hole in them. this can happen after a long time just due to bad installation.

2) feel the wall where the ducts might be. if the wall feels cold, and you think there's a duct inside, there ya go.

3) check the plenum. the plenum may have several main ducts leaving from it. One main ducts may be blocked either by dust and dirt over time, or if there is a hole in one of the ducts, insulation form the attic can get in and clog it.

4) try closing all the functioning vents in the house and see what happens

5) are you sure you have only one AC unit? maybe you have two units and one is not working.
Sometimes a house will be set up so that you can turn off an AC unit for the daytime areas of the house and only run the bedroom AC.
If this is the case, look for a second thermostat.

6) another problem can be that your attic space, even if its just the space for insulation may not have proper ventilation.
This causes the air just above the sheet rock to get very hot and makes it harder to cool. on the sides of the house there should be a vent in every peak.

7) there may be no insulation in the ceiling, if so, the sun is heating the attic/insulation space air. feel the ceiling during the day, if it's hot....

I think you have a duct problem check that first.

P.S. (cold air sinks, but insulated ducts and the blower should be enough to get the cold up to any vent)

Answer 2

New 2-story homes often have poor cooling on the upper floor. Because home design favors the "Great Room" effect, with it's open spaces, many new homes lack inner wall partitions. This lack of wall space to install ducts is the main culprit. In order to get ducts from the basement to the second floor HVAC installers must take a twisting and torturous route through the home. All these turns and the inability to find room for larger ductwork means that the right amount of CFM's are not getting to the desired areas. Builders do not want to add to their construction costs so they force the HVAC contractors to submit cheap bids. Cheap bids, of course, mean a cheap job. Or, and this too is quite possible, the HVAC contractor uses cheap, unqualified installers who do a poor job because the HVAC contractor is not following up on his crew's work. You can either install a central air in the attic (for the 2nd floor only) or go with window units upstairs.

Answer 3

It sounds like you either have a duct restriction or a crushed duct. We recommend: 1. have a licenced HVAC contractor look at the ductwork. Only pay the service fee and don't authorize the work. Get three estimates. 2. Have your ducts cleaned. Maybe the restriction is lint or dust and can easily be removed. This is the less expensive route. 3. Make sure you are leaving the warm rooms doors open. Heat needs to escape to the return duct and cannot when the doors are kept closed.

It is possible your unit is undersized for your home. I wouldn't be able to tell you though unless I knew what the climate is where you live and the tonage of your equipment.

Answer 4

YOU NEED A RETURN VENT that goes to the second floor. I had the same problem. Remember cold air sinks, so its very difficult to get the upstairs cool.

Answer 5

open all the vents on the second floor and close all of them on the first floor
it will cool off the second floor and sense cold air falls it will also keep the first floor cool

Answer 6

Have him come decrease back and verify each and every thing out. Your go back air vents ought to no longer have chilly air coming by them, The scent from the water heater should be stagnant water or mould. Have him verify each and every thing out.

Answer 7

1st floor master bedroom not receiving enough cool air even though it has 3 vents...

Answer 8

Do you have only one heat pump (ie AC unit) or two? In other words, is the upstairs on a different zone/thermostat?

Answer 9

sounds like your unit may not be large enough for the square footage..bring in a professional and see.