Q&A for How to Set a Thermostat

The common low temperature setting for regions where it gets in the 90s is 78 degrees.

Yes, when setting a higher temperature, this will lead to less cooling.

When you’re at home during the daytime, try to keep the thermostat set between 68° and 72° F (20-22° C). At night or when you’re away, set it to 62-66° F (17-19° C).

The U.S. Department of Energy recommends keeping your thermostat at 78° F (26° C) while you’re at home to stay cool and save money and energy. To be even more energy efficient, any time you’re away for more than 2 hours, set it to 88° F (31° C).

It will continue to heat/cool your house until it reaches the desired temperature; if the desired temperature cannot be reached, it will continue to cool/heat your house. A "smart" thermostat, such as the Nest, could potentially tell you your house couldn't get that hot/cold. It also can warn you about other things, such as energy consumption, how long it would take to heat/cool the house etc.

Correct.

It probably froze up - see if the lines have ice around them. If so, run the heat until they thaw out and then turn on the AC. Also, if you set your temperature too low, your unit will not turn off, thus causing it to freeze. Try putting the temperature to 71 after it has thawed out. If your unit still isn't blowing cold air, you might be low on freon.

That is an incredibly subjective question with a lot of factors to consider. You'll want to think about outside temperature, personal comfort level, and how much money you want to spend heating and cooling your house, among other things.

Look at the settings on your thermostat and either adjust the temperature so it goes down or select the "cool" setting.

It depends on your personal preferences, but 75 degrees is a pretty average temperature for heating the house.

It just circulates the air inside the room. Since you do not have an AC, the settings for "on and "cool" will just circulate the air in the room to make the air cooler.

All thermostats use an anticipator setting: it shuts off the heat before the set temperature is reached. The heat takes time to reach the thermostat. Different systems have different heat flow patterns, so you must tell the thermostat. The blower adjustment is at the furnace. Ask an expert, unless you are an expert.

The two respective temperature settings rely on the outside temperature and integrity of the system design & installation. As cold air falls to the floor and down stairways, the top floor should be set the lowest, since the attic heat impinges on the room temperature; test this idea by standing on a chair to feel the temperature difference between the the ceiling level and your standing floor level. But, once you have the top floor at your comfort level, depending on the system design, set the lower levels accordingly to your comfort level.

My Honeywell programmable thermostat has a "hold" button. This allows you to set a desired temperature, and the thermostat will "hold" at that temperature. After the hold is canceled, the programmed set time and temperature will resume to the prior setting.

Yes, but it may lead to higher energy consumption, and more maintenance cost on your unit.

It sounds like you need to call an HVAC tech.

Freon has to be professionally evacuated by a HVAC licensed technician. Then the system has to be dried and recharged.