There’s nothing worse than sweating while you’re inside your house. If you’re like most people (myself included), your first move is to turn the thermostat down to get the air conditioner running. But what if you find that your AC is already on, but it’s still hot inside? 

If your A/C is blowing cold air, but your home is still hot inside, it could be due to a simple problem like drafts or leaky air ducts. An A/C that’s not large enough for the home can also cause this problem. Be sure to check your filter and thermostat first, and open all your vents for the best airflow.

Why Is My House Hot if My A/C is On?

Reason # 1 Your Home is Drafty

A drafty house can be the source of your too-warm-for-comfort conditions. If windows and doors aren’t sealed properly, or the insulation is poor, warm air can continue to leak in faster than your A/C system can remove it. 

Older houses are more likely to have this issue than modern builds. Still, air can leak in through unexpected spaces. For example, air from an attic or around electrical outlets can make its way into your home, causing drafty conditions. Small cracks in the foundation or around the chimney may also be the culprits. 

Normally, if a drafty house is causing your problems, you’ll have the same sorts of issues in winter and may find that it’s difficult to keep the house warm, too. 

Reason # 2 You Air Ducts May Be Leaking

Like the air seeping in and out through windows, doors, and other openings in your home, air ducts can also be to blame if they’re not sealed properly. Older ducts or damaged ductwork can send your newly cooled air straight into your hot attic rather than into your sweltering living room. 

Leaky air ducts can cause your A/C system to work much harder than it should, too, meaning it could eventually start having problems sooner. And you’ll also probably notice higher utility bills as your A/C has to run more often than it would if your ducts were sealed up.

Reason # 3 Your House is Too Big for Your A/C Unit (about 40% of the time )

After working on over 1000 AC units, we've found that the size of the A/C unit you need is primarily determined by your home’s square footage. If your air conditioner is too small for your home, it simply can't keep up with the cooling demands of all that space. This often results in your A/C running seemingly non-stop and blowing cold air, yet the house still feels warm.

Additionally, if you've made additions to your home, such as adding an extra bedroom or a sunroom, your current air conditioning unit may struggle to adequately cool the increased square footage. This highlights the importance of starting with the right-sized unit from the beginning, ensuring sufficient coverage to keep you comfortable. At Rich’s Heating and Cooling LLC, we base our recommendations on extensive experience, having serviced over 1000 AC units, to ensure optimal cooling performance for your home.

installing a second ac unit can help

Reason # 4 Your Vents Are Closed

If you notice your house is too hot in certain rooms or only in one side of the home, it could be because the vents are closed. Make sure your air vents are open to ensure proper airflow and good circulation throughout your house. 

You might think closing vents in unused rooms will help make the rest of your house cooler. In fact, closing off vents can make your A/C work harder as it tries to push air all the way across your home without any exit points along the way. Not only that, but if you’re trying to cool down the entire home, you’ll want to have that conditioned air flowing throughout the house, not just into certain spaces. 

Reason # 5 You Have a Dirty Air Filter

Regularly changing your A/C filter is one of the simplest tasks you can do to keep your system working properly. Changing the filter according to the manufacturer’s recommendations is critical for the A/C system’s performance. If you don’t feel like your A/C is keeping your house as cool as it should, the filter should be one of the first things you check. 

When the filter gets clogged with dust, dirt, debris, pet dander, and other contaminants, the A/C unit will struggle to move air through the system. Left unchecked, it may become overworked and eventually break down.

We preform both commercial and residential HVAC maintenance. changing ac filter can help the system work better

Reason # 6 There’s No Shade in the Room

The temperature in one room compared to the next can vary significantly just based on whether there’s a tree or some other shade outside. Using window shades and window coverings can also help reduce the temperature considerably. 

If your house feels hotter during the sunniest parts of the day, this could be your issue. Even with your A/C on, the added heat from the sun might be too much for your A/C to keep up with. If this is the case, you could consider installing new windows to block UV rays, or you could use heavy-duty window shades to help keep the sun out. 

Reason #7 Need a New Thermostat

A faulty thermostat can cause problems with your A/C system, especially if it’s not calibrated properly. The thermostat works by reading the temperature in the room, then signaling the A/C to turn on or off depending on your temperature settings. 

When the thermostat isn’t working correctly, it may misread the temperature in the house, preventing your A/C from operating when it should. Sometimes, the issue is something very simple, like replacing the batteries. In other cases, the wiring may be damaged or loose inside the thermostat. 

To find out if the temperature is accurate, use a thermometer to check the temperature compared to what’s displayed on your thermostat. 

Reason # 8 The fan is Not Working

If your A/C fan isn’t working, it could be due to several different reasons. It could be a power issue, a frozen evaporator coil, or even a dead capacitor. To find out what’s going on, you’ll first need to know whether the problem is with the condenser fan located outside your house or the blower located on the inside unit. 

If your fan isn’t running when you think it should, first check the settings on your thermostat. There is typically an “ON” setting, an “OFF” setting, and an “AUTO” setting. If the fan is switched off, try changing it to “ON” and see if you hear or feel it kick on. Another simple fix could be checking the circuit breaker to see if that’s the issue. 

More complex problems will require a service technician, so it helps to check these simple items first, just in case. 

If your A/C isn’t keeping your house cool, several issues could be causing the problem. While some of these can be resolved with simple troubleshooting, more serious problems may require professional assistance.

If you're not comfortable performing the steps we discussed, always call a professional. Reach out to Rich's Heating and Cooling LLC, your trusted Heating Repair, Air Conditioning Repair, and HVAC Company, at (732) 433-0068.

Don’t hesitate to call a technician as soon as you discover the problem - waiting can make the issue worse over time. Take action now to ensure your home stays cool and comfortable.