However, the truth is an oversized system will not do a better job of cooling the house or provide any extra comfort over a properly sized unit. Air conditioner size is calculated in BTU (British Thermal Units) and tons, and measures how much heat the system can remove from the home in one hour.
Larger AC units may cool your home faster, but that means the cooling cycle will end faster and they will shut down faster – only to cycle back on again before very long. This rapid cycling creates a lot of wear and tear on the system, shortening its life and increasing the maintenance needed to keep it running.
Larger unit may be more efficient (larger condensers generally are), but make sure you don't oversize it. If the unit is oversized it'll cycle more frequently, which is hard on it. Oversized can also cause some issues with humidity if you have any outside air connections.
When temperatures exceed 100 degrees Fahrenheit outside, setting your air conditioning (AC) to around 75-78 degrees Fahrenheit is generally considered efficient. Here are some reasons for this recommendation:
Homes measuring 1,000-1,500 square feet: You'll need a 2-ton unit, which corresponds to a cooling capacity of 24,000 BTUs per hour. Homes measuring 1,500-2,000 square feet: You'll require a 3-ton unit, equivalent to 36,000 BTUs per hour. Homes measuring 2,000-2,500 square feet: A 4-ton unit is necessary.
3.5 Tons (42,000 BTUs): Suitable for homes ranging from 2,100 to 2,400 square feet. Installation cost ranges from $3,800 to $5,500. 4 Tons (48,000 BTUs): Suitable for homes ranging from 2,400 to 2,700 square feet. Installation cost ranges from $4,000 to $6,000.
Just because the outdoor temperature is above 100, the Ideal temperature to set your AC unit to doesn't change — it's 78 degrees. Higher temperatures in the home are to be expected when the weather is hotter than usual, but your thermostat can still be set the same as if it were a lower temperature outside.
Cooling a house from 80 to 72 degrees is a common goal for many, especially during the peak of summer. On average, this process takes roughly two and a half to three and a half hours.
On average, an air conditioner running in good condition should take about 15-20 minutes to drop the temperature by 1 degree in a standard-sized room. However, factors like outside temperature, unit size, and insulation quality can affect this timing.
Since an oversized AC is too powerful for your home, it will quickly cool your home then shut off, which can raise your energy bills and wear out your AC (from all the starts and stops).
An oversized AC system can be just as bad for your home as having one that isn't big enough. You may think a larger unit means your home cools quicker or could save you money on electric bills. Unfortunately, neither is true, and it can cost you more in the long run.
Installing an air conditioner with too many BTUs for the size of your home will cause it to run for shorter periods of time, thereby causing less-than-ideal temperatures and humidity within your home, more wear and tear on your HVAC system, and higher utility costs.
Is It Better to Oversize or Undersize AC Unit? Neither oversizing nor undersizing your AC unit is ideal. Both scenarios can lead to issues with efficiency, comfort, and longevity of the system.
If your AC is running but not cooling, it could be due to a dirty air filter, incorrect thermostat settings, a malfunctioning thermostat, a refrigerant leak, dirty condenser coils, blocked vents or ducts, a faulty compressor, frozen evaporator coils, or electrical issues.
Most people know that turning up the thermostat on their air conditioner to a higher temperature will result in cooler air blowing from the vents. However, there is a point at which increasing the temperature any further does not make the air cooler – it just uses more energy and costs more money.
If it's 90 degrees outside, most people would set their AC to a perfectly comfortable temperature of 68-72°F.
In general, 80 degrees is too hot for a house if people are inside. However, if people aren't home during the day or for vacation during the summer, an indoor temperature of 80 degrees can save energy until you return and lower the temperature.
Sleep experts believe the best temperature for great sleep is between 68-72 degrees Fahrenheit. But in addition to making you uncomfortable and interfering with healthy sleep patterns, being too hot at any time of day or night can cause health risks like dehydration and heat stroke.
Best AC Temperature Settings While You Are Home
As you consider the most comfortable room temperature for your lifestyle and family, keep in mind that for each degree that you set your thermostat above 72 degrees, you can save up to 3% on your energy bill.
There are benefits to having your air conditioner set to “auto” and “on.” The benefits of the “auto” setting include higher efficiency, lower energy bills, better humidity control, less wear and tear on some components, and quieter running.
For instance, if it's 100 degrees outside, aim to set your thermostat to at least 80 degrees. Adhering to the 20-degree rule maintains energy efficiency, prevents strain on your cooling system, extends its lifespan, and promotes lower energy bills and consistent indoor comfort.
HVAC Pro Cost
Most people pay $500 to $2,500 in labor for AC replacement.
Every air conditioner ton can efficiently cool around 500 square feet of a home. Depending on the system's model, this estimated square footage can be slightly more. This being said, a 3-ton AC system is a reasonably sized unit for a 2,000-square-foot home.