What is the best setting for home air conditioning in summer season. Tks

The cheapest on your electric bill is 78 degrees. It is also the most comfortable, not too hot and not too cold.

I live in an apartment so I keep mine at 76. There is no 'best' setting, it is only what you think is the right balance between electricity bill and comfort. 75-79 is what most people think.

Remember that the thermometer on the thermostat is a very cheap meter and could be of by 5 degrees so if you set your thermostat at 78 and it is freezing you try a higher number or if you are set at 72 and still hot maybe it is the thermostat that is off.

This question really depends on one major thing, Is your system properly sized? If not you may find that at 77-78 it may still feel humid. There is no "best setting", it all depends on your comfort, I go into many houses each week, and I'd say the average set point for most home owners is between 74-and 78 in my area, I also agree with the above answers, it also depends on how much you can afford your untility bill to raise.

Also make sure your tstat is calibrated using a few other thermometers to test it. Some tstats are off by a few degrees from the factory, especially the horizontal White Rodgers ones. Those can be off by 3 degrees cooler.

What should i set the termostat at to turn on the heat

WHAT SHOULD i SET THE TERMOSTAT AT TO TURN ON THE HEAT

I SET IT AT 78 BUT THE SETTING DOES NOT MOVE FROM 67

I'd say you have some sort of problem with your system. Might start by checking your filter. You are better off starting your own thread,your questions will get many more answers.