I have to set my a/c thermostat to 80 degrees to make it feel like 70 degrees in the house. Why is that?

Obviously the mechanism is OUT OF Calibration. Many NON digital thermostats still function by means of a small vial filled with Mercury. If that has become dislodged; moved; broken; etc.; The thermostat has no practical means by which to function properly.





More valid might just be to purchase a new thermostat.





Silly answers might say "Close your windows when the AC is on"???





Steven Wolf

I have to set my a/c thermostat to 80 degrees to make it feel like 70 degrees in the house. Why is that?
There could be a few things "wrong".





First of all, if you live in an extreamly humid area, expecially if you grew up without air conditioning, you'll typically have a higher tollerance for heat. Working in a 110 degree enviroment normally I'll have the air conditioner set about 85 for the first week I'm home after long underways. As the airconditioner reduces humidity, it will feel cooler than it actually is.





Second, it could be a dirty air filter. If the air filter is clogged with dust and such, you won't get design air flow for the unit, causing the TXV to overcorrect for a given temperature. Air comming out of the vents will be cooler but there won't be as much of it, causing a net reduction in cooling.





Third option is the sensors. For analog systems if there are corrosion products or damage to the bimetallic element the set temperature will indicate either higher or lower than the sensed set temperature. Normally the only way to fix the analog set switch is to replace it. Digital sensors can either become corroded, or dirty, causing an insulating effect and throwing off set temperature in relation to actual temperature.





A fouth possibility is a refrigerant leak. As R-134A systems develop leaks non condensable gasses make the compressor and expansion process much less efficent, causing the whole system to have to work harder to maintain the same temperature. If you're setting the temperature high, this is most likely not the issue.





One last possibility is location of the thermostat. If your thermostat is on an exterior wall, next to a window, or other source of heat, the thermostat element will see a higher temperature and correct to the point where it senses set temperature. One of the most common "offenders" that cause this are dimmer switches with slide resistors.





If all else fails you can always call a HVAC tech and they should be able to find a specific problem, and if anything else, ensure your air conditioning system is working properly.
Reply:It sounds like you have a mechanical type thermostat and it is probably not level. You could save a lot of money by replacing it. You can do it yourself and save. For more info check out the thermostat page at my source.
Reply:what are u talking abt...ACs dont heat air up, atleast the ones i know...





u will die if u live at 80 C..
Reply:heat rises!?
Reply:If it is a digital stat sounds like the sensors is messed up. If it is a normal one your mercury meter is off, you could probably make it more accurate by popping the cover off and twisting it up or down. You can’t miss it, it is a tube filled with mercury.

lady palm