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7 Reasons Why Your House Is Hot Even With Air Conditioning

Brionna Farney

Brionna Farney

Is your home still hot, even with the air conditioner set to a pleasant, cool temperature? Check out these possible solutions to your problem, and stop sweating in the comfort of your home.
Thermostat

Paying your energy bills every month, but still suffering in a warm, uncomfortable home is less than ideal.

If you regularly set your AC to a specific temperature, but it never quite reaches it, there might be an issue with your unit or your home itself.

Window and central air conditioning units are complex systems.

If a part is dirty or slightly worn out, the cooling mechanisms may stop working as efficiently or altogether, making your system overworked.

That means you could also see a bump in your utility bills, even if your home doesn't feel sufficiently cooled.

Consider the reasons below why your home is still hot, even with the air conditioning on.

Then, consult an HVAC professional and get your home temperature—and energy bills—back down to your comfort level.

There's a Blockage in Your Air Conditioning System

Starting with a simple and somewhat obvious fix: Make sure nothing is blocking your air conditioner vents or that they are open.

For example, placing tall furniture in front of your window unit will restrict air circulation and limit your AC’s capability.

Blocking your AC could also lead to a false temperature reading at the internal thermostat.

If your air conditioner thinks it is cooler in your room than it actually is, it will not run as often as it needs to.

Similarly, ensure your vents are not blocked if you have a central air conditioning system with ductwork. In addition, check to see if any of your AC vents are closed.

Even in rooms you rarely use, you should keep all of your ductwork vents open.

When vents are closed, your AC’s blower works in overdrive to move the air in your ducting past the closed vents.

This extra effort can cause your AC to take longer to reduce your home’s temperature, and it may restrict it from ever reaching your desired temperature.

Another major reason you could have blockage is that you haven't replaced your filters in your central air system.

The filters need to be replaced at least once a year and in many cases two to four times a year, depending on your usage.

What To Do

If you have a window AC unit, make sure nothing is blocking the vents.

If you have to place furniture in front of your window unit due to room constraints, provide 18 inches to 24 inches of clearance between the two.

If you have central air conditioning, make sure all your vents are opened, and nothing is restricting the flow of air out of the vents.

Check the filters in your HVAC system and replace them if needed. If you are using heating and cooling throughout the year you may need to change filters every three months.

You can put reminders for yourself or subscribe to a filter delivery service which will remind you.

Your AC Unit Is Too Small Or Old

If your central or window AC unit is too small for the size of your space, it will not be able to keep up with the thermal load.

In other words, your home will never reach your desired temperature setting and will likely remain just a few degrees too warm all summer long.

An undersized AC unit can happen for several reasons, including the unit in your home wasn’t sized correctly from the start, you modified your home and increased the square footage, or you purchased a window AC unit that was not powerful enough.

Likewise, if you have an old unit whether window or central, it may not be as efficient as newer models, and work extra hard to keep up with the cooling.

As a matter of fact, like a unit that's too small, it may never quite reach the desired temperature.

What To Do

Window air conditioners are offered in a range of sizes based on BTUs or British thermal units.

A BTU measures how much energy your AC unit needs to remove heat from your home over the course of one hour.

Air conditioner manufacturers provide a room square footage range based on the BTUs for each unit.

For example, an 18,000 BTU air conditioner can typically handle cooling a 700 to 1,000 square foot space.

When buying a window AC, review the recommended room size for your unit.

If you already own a window AC, determine if you need to buy another one to supplement your needs.

In addition, remember that even if your old model claims to be providing a certain number of BTUs, after some time it becomes difficult for that unit to run as efficiently anymore.

Central air conditioning works in the same way—your AC unit must be appropriately sized for your home.

If you have recently added on to your home, finished an unfinished space, or made other modifications, consult an HVAC professional to see if you need to upsize or upgrade your AC unit.

Your AC Unit Needs Servicing

Managing your home requires reciprocity: give and you shall receive.

If you take proper care of the systems throughout your home, you can generally expect them to function properly for you.

The same goes for your air conditioning system.

If your AC unit has not received regular service and upkeep, that could be why it is not cooling your home.

Unclean or worn mechanical parts will not function as efficiently as those which receive regular maintenance.

Common AC issues that lead to poor performance are a lack of refrigerant due to a leak, dirty or worn condensers, and filthy or damaged air filters.

What To Do

Hire an HVAC professional to inspect and service your AC unit. The inspection will be a lengthy process if it has been a while since your last service.

The unit will require cleaning inside and out and replacing any worn parts.

Before the technician leaves, get an annual inspection on the books for your unit.

Most homeowners have a recurring air conditioning inspection scheduled for the spring of each year, so your AC is ready to go for the summer season.

Your Air Ducts Are Leaking

Central air conditioning requires ductwork to send cooled air throughout your home.

Unfortunately, it is not uncommon for this ductwork to eventually possess holes or gaps that allow cooled air to leak out.

As ductwork ages and is constantly used, holes can develop in the metal or seals can break between sections.

This escaped cooled air is likely released in your attic and never reaches the rest of your home.

What To Do:

Consult a professional HVAC technician to evaluate your entire HVAC system.

This inspection will evaluate your AC system itself, then a close-up inspection of the ducting throughout your home.

If any holes or gaps are located, the technician will use either a mastic sealant or metal tape to seal the air leak.

These two repair options are long-lasting; avoid using duct tape that may wear away over time.

Your Home Isn’t Properly Sealed

If your home feels drafty or has any holes that lead to the exterior, cooled air will find its way outside and warm air inside.

In addition, as homes age, the building materials often wear away, leaving holes, gaps, and cracks exposed to the exterior environment.

Not only are holes in your home’s exterior a place for water, debris, or insects to enter, treated air from the inside can easily escape.

In this case, your air conditioner will continue to cool your space, but never keep up with the demand.

What To Do

Your best bet is to consult a professional to evaluate the exterior of your home for air tightness.

The contractor or building envelope expert will start by inspecting your home for any cracks or holes.

Small exterior openings can be sealed with a simple caulk product.

However, if the gap is big enough, it might require new sections of insulation, waterproofing, or siding.

The professional will also inspect the gaps around doors, windows, and other penetrations for potential sealing issues.

Use caulking around these openings to close up any holes, and if needed, replace worn weatherstripping around doors.

Your Windows Are Inefficient

Inefficient windows are unable to keep cool air inside your home.

Single pane glass windows, prevalent in older homes, only have one layer of glass to keep hot air outside and cool air inside—not enough of a barrier to allow your home’s AC system to run efficiently.

The frame around your window is also a factor. Outdated window frames are poorly insulated.

Additionally, your windows may be damaged, cracked, or otherwise deteriorated, allowing a place for cooled air to escape.

What To Do:

If your windows are dated and inefficient, it is likely time to upgrade.

However, replacing your windows can be a costly project, so consider replacing them just one room or one level at a time.

Often, programs are available that supplement the cost of installing energy-efficient windows or implementing other eco-friendly home trends and upgrades.

Do your research to determine if any credits or rebates are available in your area.

Energy-efficient windows have either double or triple pane glass—these added layers make it more difficult for air to transfer from inside to outside and vice versa.

The window frames are also adequately insulated. An added benefit of improving your home’s windows: reduced energy bills.

Your Home Is Poorly Insulated

This issue goes hand-in-hand with poor sealing and inefficient windows. The higher quality and better condition your exterior building materials are in, the better your air conditioning will perform.

Many older homes lack adequate insulation, making it difficult for your home to retain its heat in the winter and coolness in the summer.

Poor insulation allows treated air to escape through the walls. Adequate insulation slows heat transfer, and may even prevent it entirely.

What To Do:

There are multiple ways to remedy a poorly insulated home. Start by contacting a building insulation provider and requesting an inspection.

They will provide expert advice on improving your building envelope as a whole system.

Possible solutions to improve your home’s insulating properties include installing rolled insulation in your attic or basement or injecting spray foam insulation directly into your existing walls.

In extreme situations where your insulation is extremely lacking, the expert might suggest removing interior drywall or exterior siding and installing brand-new, high-performing insulation throughout your home.

DIY Air Conditioner Repairs vs. Hiring a Pro

While lots of savvy-homeowners are happy to get their hands dirty and save a few bucks by doing home repairs themselves, when it comes to air conditioning systems, DIY is not always the best choice.

If you have a window AC unit that is no longer performing or is too small for your apartment or home, head to the store and buy a new one.

Otherwise, leave the air conditioner repairs to the pros.

A professional HVAC technician will view your AC system as a whole and inspect every potential pain point, from the air ducts to the unit itself, internally and externally.

This ensures every issue is caught and your system can be wholly repaired.

If your AC unit is not the problem and your house itself needs to be assessed, contact a local general contractor with excellent reviews and a positive track record to do so.

Ask the GC and their team to inspect your home’s insulation, exterior sealing, and the condition of the doors and windows to make a recommendation on the required repairs.

Often, it is best to have more than one contractor complete an assessment to get multiple opinions and make an informed decision.

In the dog days of summer, your home should be an escape from the heat. Ensure your air conditioner is in top-notch shape by keeping it clean and free from obstructions.

The condition of your home is just as important as the state of your AC when trying to keep your house cool.

Check your home’s exterior and seal any holes or gaps to ensure your cooled air is not escaping.

Consider replacing outdated doors with newer, energy-efficient models if you have outdated doors or windows.

Also, be sure to prepare your home for the summer season a few months prior to the heat arriving.

Schedule an annual AC inspection in the springtime, so your unit is serviced and ready to go.