Your house takes long to cool at night because building materials (walls, roof, furniture) absorb the day's heat and slowly release it, a property called thermal inertia, while poor insulation and air leaks let warm outside air seep in, fighting your AC and preventing cool air from escaping. Internal heat sources, like appliances and people, also add to the problem, making your cooling system work harder against this retained and incoming heat.
The AC System Has a Dirty Air Filter
A dirty air filter is one of the most common reasons why an air conditioning system takes a long time to cool a home. The filter is responsible for removing dust, pollen, and other airborne contaminants from the air.
Clean the Thermostat
Sometimes, when the room temperature doesn't match the thermostat setting, the problem could be dirt buildup on its interior parts. A dirt coating around the inner components may create excess heat and cause the thermostat to give the wrong readings.
On average, a well-functioning air conditioner can lower the temperature in your home by one degree every hour. So if your house is sitting at 80°F and you want to bring it down to a cool 72°F, you're looking at about 8 hours.
How to tell if your house is poorly insulated
To keep a poorly insulated house cool in the summer, you can invest in the right ceiling fans, optimize existing fans, flush out hot air in the evening, update insulation, weatherize windows and doors, switch to no-heat lightbulbs, and consider installing a whole house fan.
Common symptoms may include irritated, itchy, watery, or burning sensation of the eyes, nose, or throat, or itchy skin or skin rashes. Occasionally, some people report breathing difficulties, especially if they are asthmatic or have other breathing disorders.
The 3-minute rule is a simple but important guideline: wait at least three minutes after turning your air conditioner off before turning it back on. That short pause gives the refrigerant pressure in the system time to equalize.
How cool should my house be if it's 100 outside? Your AC can typically cool about 20°F below the outdoor temperature, so if it's 100°F outside, maintaining 78–80°F indoors is reasonable.
How long should it take AC to drop 1 degree? 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.
The "AC 5000 rule" (or $5,000 rule) is a common HVAC guideline: multiply your air conditioner's age (in years) by the repair cost; if the total exceeds $5,000, replacing the unit is generally more cost-effective than repairing it. This rule helps homeowners decide if it's better to invest in a new, more efficient system versus sinking money into an aging one, but it's a guideline, not a strict law, with other factors like energy efficiency and warranty also influencing the decision.
There are 7 symptoms that can help your identify if you have a bad thermostat:
Without regular maintenance, even a properly sized and newer air conditioner can struggle in the heat. Dirty filters, clogged coils, low refrigerant levels, and blocked drain lines restrict airflow and heat exchange, forcing your system to work overtime.
If the summer temperatures have you needing to chill out, try our tips.
Well, certain problems can prevent an air conditioner from properly cooling down your home including: A dirty air filter. A blocked condenser. A refrigerant leak.
The following tips will be useful.
The AC 20-degree rule is a guideline suggesting you shouldn't set your thermostat more than 20 degrees cooler than the outside temperature, as it prevents your air conditioner from overworking, saves energy, reduces wear and tear, and improves dehumidification, especially when it's very hot outside. For example, if it's 95°F outside, your thermostat should be set to at least 75°F to keep the system efficient.
Most air conditioners should never run below 62°F outdoor temperature. Even though 62°F falls within the manufacturer's 60-65°F range, operating at this temperature puts your system at risk.
As shown in the table below, heat indices meeting or exceeding 103°F can lead to dangerous heat disorders with prolonged exposure and/or physical activity in the heat.
According to the U.S. Department of Energy, the best AC temperature for saving energy is 75–78°F (25.5°C) when you're at home and need cooling. Increase the temperature by about 7°F when no one is home to significantly reduce energy consumption.
Steps for Checking Refrigerant Levels
Are your walls, floors, and ceilings cold to the touch in the winter? If so, it's a sure sign that your insulation isn't working as well as it once was. These parts of your home should feel dry and warm when you touch them. If they don't, it means cold air from the outside is penetrating your home.
Short-term Exposure
The symptoms of irritation are often nonspecific, temporary, and may include itching, coughing, or wheezing. High levels of exposure to airborne fiberglass may aggravate existing asthma or bronchitis-like conditions.
If left untreated, mold exposure can lead to serious health issues, including heart or lung disease or even death. Breathing in mold spores can lead to a serious lung infection called aspergillosis or “mold syndrome.” The symptoms of mold syndrome include coughing, wheezing, and shortness of breath.