You may believe running your air conditioner faithfully during summer’s hottest days is enough to keep your home cool. This is not the whole truth: there are many factors that can compromise the air conditioning’s ability to keep your home at the most optimal comfort level. What you Chicago HVAC team is trying to say here is: your air conditioning system cannot alone do the job of keeping your home cool as a cumber.

Your air conditioner unit needs assistance to help it run as efficiently as possible. You’ll be surprised to know how many things can cause your home to retain more heat than it should. In this blog, we will explain first how heat in your home happens; what problems with the air conditioning may be impeding its ability to do a sufficient job of cooling your living spaces; and some guidelines on how to support your air conditioner in doing its work.

Why is My Air Conditioner Blowing Hot Air Instead of Cold?

The laws of physics dictate hot air (conduction) moves towards cool air (convection). Concerning your home, heat from outside is absorbed by your ceiling, windows, walls, and doors. The foundation of your house also absorbs heat. So, you could say the entire infrastructure of your home is under assault by heat waves. No wonder the A / C is not cooling enough. To continue, if your home absorbs heat at a higher rate than the air conditioning can eliminate it, the temperature goes up. This explanation answers the concern: my A / C is blowing but not cold.

In the face of all these factors adding to the heat gain of your home, there are plenty of steps you can take to resolve the issue of your home A / C not blowing cold air, lessening the burden on your air conditioner unit to do all the grunt work of cooling. Assuming your air conditioning system has been completely inspected, and all components are in working order; the remedies for the home A / C blowing hot air, even in the midst of oven-like heat, follow.

Why is My Air Conditioner Not Cooling the House?

Sealing Cracks

A common source of high heat gain, which interferes with the air conditioner’s ability to cool your home, are minute cracks found around the perimeters of doors and windows, which let in heat from the outside. An ingenious method to discovering where these cracks are is to light a stick of incense. When you are near doors and windows, observe if the incense smoke is streaming vertically or horizontally. If the incense has a horizontal tail, that tells you a crack is present which needs sealing.

Besides sealing cracks around the window, you can also buy heavy-weight drapery and blinds, which will further lessen heat gain. In this way, you help your air conditioning unit to optimally perform its cooling operations.

My A / C Isn’t Cold

Roof Replacement

When the time comes to have a new roof installed, it’s an opportunity to reduce heat gain in your house. Roofing shingles both absorb and radiate heat. Heat from the roof works its way into your home via the attic and is absorbed into the ceiling.

One solution for your attic, where temperatures have been known to rise as high as 150 degrees and beyond, is to purchase an attic fan. Having a dedicated thermostat for just the fan will help to determine at what temperature the fan will turn on to keep the attic cool, holding heat gain at bay.

Another facet of shingles, which also adds to the heat gain and affects the air conditioning’s cooling properties, is their color. If they are dark they absorb more heat. This helps in the cold weather months when your home is crying out for heat, but in hot weather it only creates more heat gain. The next time you’re ready to replace the shingles talk to your roofing contractor about what colors are best for both summer and winter months.

My Central Air Conditioner is Blowing Warm Air: Other Reasons

Preparing Meals

When you turn on the stove or oven in summertime, you force your air conditioner to toil harder to address the high heat gain these appliances create. A good rule-of-thumb to follow is once the outdoor temperature soars over 90 degrees, cook outdoors on your patio or sundeck. And to put a fine point on it, your dishwasher, clothes washer, and dryer also add to the heat-load demand. Wait until later in the evening when the temperature drops, ideally just before you retire, to turn on the dishwasher, or do a load of wash.


Desktops and laptops as well as TVs produce heat, so shut them off when you’re not using them.


Shower steam equals heat gain, so ensure everyone in your home uses the ventilation fan in the bathroom.

Water Heater

The water heater is yet another source of heat gain in your home during the summer. Use an insulating blanket to wrap the water heater in.As you can see now there are many reasons your air conditioner is blowing warm air in the house. Take the steps we’ve suggested to bring cooling comfort to your home.