There are a few possible reasons why your AC unit might not be going lower than 75 degrees. Dirty air filter: A dirty air filter can restrict airflow, which can make it harder for your AC unit to cool your home. If your air filter is dirty, it's recommended to replace it every 1-3 months.
Air conditioners make homes more comfortable on hot and humid days. So, it can be frustrating when the AC is not cooling below 75 degrees, even if it has been running for hours. Many factors can cause this issue, including clogged filters, refrigerant leaks and the wrong unit size.
One possible reason your AC is not reaching the set temperature is that the thermostat could be dirty. If dirt, dust, or other debris has accumulated within the thermostat box, it can cause the wires to heat up or other issues. Thermostats are cleaned during routine HVAC maintenance to help prevent this from happening.
Your AC might not cool properly due to thermostat issues, an undersized unit, or extremely high outdoor temps—so check those first. Keep an eye on airflow—replace clogged filters every 3 months, and make sure vents and ducts aren't blocked for efficient cooling.
Answer: If the thermostat is set at 70 but the actual temperature is 75, it means there's a problem with the actual AC system, not the thermostat. Assuming the outdoor unit does not run it could be anything from a bad capacitor, to a tripped breaker, to a bad contactor.
It may just be time for a service check or a new thermostat. Over time wires can become worn out and systems become outdated, becoming less efficient and accurate.
There are a number of reasons why your air conditioner might be running but not cooling. It could be an issue with the thermostat, the compressor, or the evaporator coils. Or, it could simply be clogged with dust and debris, which is preventing it from working properly.
If it's just you and your spouse, you may be fine with the temperature set at 75-77. But if you have kids and pets running around, or you're cooking and using your oven, these things can all raise the indoor temperature noticeably. So, you might find a temperature setting in the 72-74 range more comfortable.
Clean your Air Filters, Vents, and Ducts – A clogged air filter will struggle to meet the thermostat's set temperature since the dirt and debris buildup prevents air from circulating through the vents. And as airflow into living spaces drops, so do comfort levels.
For many of us, 70 degrees is the ideal indoor temperature, but when it is close to 100 degrees outside, your AC unit will be working quite hard to meet these expectations. Consider setting your thermostat at 75 degrees to 80 degrees in your home if the outside temperature is approaching triple digits.
Clean or replace the AC air filter.
A dirty air filter can cause your AC to not cool properly. Over time, dust and debris can accumulate on the filter, restricting airflow and making it harder for your AC to cool your home. Check your air filter and if it looks dirty, clean or replace it.
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.
Yes it is normal. It has to do with the "swing" or differential on your thermostat. This is the amount the thermostat allows the temperature to rise above your setpoint (or fall below setpoint for heat) before the system comes on again.
Sometimes, your furnace or AC system won't hit the thermostat temperature because the thermostat isn't correctly calibrated. This can be a common issue with new thermostats, and also often occurs after a power outage or when the thermostat's batteries are running low.
If it doesn't go below 76 then your central air conditioning unit is probably undersized or the house is old and not insulated properly. Do you have old doors and windows that are letting hot air in? Close off the vents in the basement and make sure air isn't still flowing through them.
Common Causes of an AC Running Constantly
If your AC cooling cycles last more than 30 minutes or run all day, you likely have one of the following common AC problems: Thermostat fault. Dirty or clogged air filter. Low refrigerant.
When the temperature soars, your AC has to work harder to maintain a comfortable indoor climate. It needs to remove more heat from your home, and if it's not properly maintained or appropriately sized for your space, it can struggle to keep up.
Dirty Air Filter
If your air conditioner isn't keeping up with the heat, your air filter may be to blame. A dirty air filter can obstruct the airflow path through the unit.
The normal grading range is from 55 to 100. The number grades correspond to letter grades as reflected in the chart below. The minimum passing grade is 70 (C). Any grades between 55 and 69 (D and F) are considered failing grades for which unit credit is not earned.
If the temperature is set to 74°F but the thermometer shows 78°F, you will have to recalibrate the thermostat to account for this 4-degree deviation. Even with older AC units or furnaces, you might have to recalibrate your thermostat from time to time.
Most modern thermostats will have a clearly marked reset button inside the panel. It's usually small and recessed, so you might need a pointed object like a paperclip to press it. For those wondering specifically how to reset air conditioner thermostat models, the process is generally the same.
Yes, you should turn off your AC if it's not cooling.
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.