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Look for a company who does energy audits in your community. They can help you assess your situation, how efficiently your components are operating, and make recommendations on how to improve it.
My AC is never on "all" the time, day and night. Its set to auto (I also have on/off/auto honeywell digital thermostat) and I have dual zone for a 2 story both set to 75 degrees and my electric bill in the summer is around $200 and thats combined with gas using Coserv. OP, if you leave your AC on all day and night, your eliectric bill WILL be high. What I suggest is, and this has happened to my mother-in-law's home, is to pull the thermostat off the wall and re-insert back into the wall connection. Or push your thermostat against the wall. It will make all connections tight and hopefully work again. Make sure all vents are opened in all rooms. Also, make sure both thermostats are running at the same temp. Also, is your attic really hot and non-ventilated (soffits)? Your AC is fighting against the temps in your attic so it could be pushing hot air from the beginning. You may need an exhaust fan and some radiant barrier in your attic to cool down the attic. What you can do is get a infrared laser thermometer from HD or Lowes and get a reading of your vents. It should be pushing cold air 10 degrees cooler than your thermostat. Anything higher, then you may need a freon refill. Also, use shades. Low-E glass will cool your house even more.
It looks like your AC is running quite efficiently.
I tried taking the t-stat out and pushing it back in. All seems to be connected correctly. I also have an infrared temperature gun that I use all the time to check the temperatures. At the coldest register upstairs, the temperature is 60, and at the least coldest register, the temperature is 67 and the temperature at the in-take is around 80. So there is a difference of about 14-15 degrees between the in-take and the least cold register. This is all when the t-stat is set to 78 for upstairs.
I also have energy efficient windows, 16" insulation in the attic, radiant barrier and soffits installed in the house. In fact house was built in end of 2010 and it has hardly ever been lived in. I know my attic is hot, I have been up there when it 95 outside and the attic was blistering hot. I am also thinking of putting couple of attic fans but I am not sure how beneficial they will be.
I am thinking about calling the contractor as I have tried many things but none seem to help.
Here is my conclusion on all this.
The room with the t-stat on the 2nd floor does not get much air from the register because most of the air is going to the register on the 2nd floor that is blowing air to the family room downstairs. This is why the downstairs is cool and the downstairs AC is not running. But this also causes the upstairs registers to get less air. The t-stat room gets even less air because its far away from the AC unit.
If I can somehow close the duct that's blowing air downstairs, I think the issue will be resolved. But again its just my personal opinion. I know that I am questioning how the builder configured my AC units and ducts in the house and this makes me think that I might be wrong cause the builders mostly do not makes mistakes like that. Hence, this makes me clueless once again and I am back to point 0.
I think I will try few other things like getting a new t-stat with +- 2 degrees tolerance, switching the t-stats with each other and other ideas here and there and if something works I will let you all know.
I don't understand why the room with the thermostat upstairs has the least air flow but the unit runs on a short cycle. I'd throttle the register back some on the air supply going to the family room, set the upstairs thermostat to 78 and the downstairs thermostat to 76.
I am thinking about calling the contractor as I have tried many things but none seem to help.
Here is my conclusion on all this.
The room with the t-stat on the 2nd floor does not get much air from the register because most of the air is going to the register on the 2nd floor that is blowing air to the family room downstairs. This is why the downstairs is cool and the downstairs AC is not running. But this also causes the upstairs registers to get less air. The t-stat room gets even less air because its far away from the AC unit.
If I can somehow close the duct that's blowing air downstairs, I think the issue will be resolved. But again its just my personal opinion. I know that I am questioning how the builder configured my AC units and ducts in the house and this makes me think that I might be wrong cause the builders mostly do not makes mistakes like that. Hence, this makes me clueless once again and I am back to point 0.
I think I will try few other things like getting a new t-stat with +- 2 degrees tolerance, switching the t-stats with each other and other ideas here and there and if something works I will let you all know.
Thanks so much.
I think you can have inline fans installed in the ducts to boost output through certain ducts, but obviously you need a professional to evaluate and install that sort of thing. Closing off a vent should be easy - you can get these vent covers which are magnetic flaps to cover vents. If you have a 20°F drop across the register and intake, then I think that your system is cooling just fine. The issue may be in how air is flowing throught the system, as you suspected.
I have similar situation (2 story home with zoned heating & cooling systems). My upstairs cooling unit runs constantly while the downstairs unit runs very little. I have been considering running both cooling systems at the same time, but redirect the downstairs cooling system into the upstairs duct work to substantially increase airflow & cooling capacity to upstairs.
I would redirect downstairs unit by connecting it via a shunt (add a duct from downstairs plenum to upstairs plenum) & add a manual damper valve to downstairs plenum that could be closed & prevent cooled air from going to downstairs duct work, but redirect in into the upstairs ducts.
This would increase ability to cool upstairs & even the wear on A/C units.
I was wondering what others think about this idea.
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Redirect Downstairs A/C unit to Upstairs Ductwork
