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For Homeowners

7 Most Common HVAC Problems and How To Fix Them

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Most common AC problems

When you have a problem with your HVAC system it can put a stop to your life in a hurry.  While some of these common HVAC problems are a quick DIY homeowner fix, others require a professional to repair.

A large majority of these problems are simply due to a lack of maintenance, and if left unattended for too long can add up to a wallet busting bill from your local repair man.  We suggest that all homeowners keep a routine schedule when it comes to HVAC maintenance, which at a minimum should be annually.



Regularly scheduled maintenance for your heating and cooling system by a licensed and certified HVAC contractor is a MUST to keep your system running without breakdowns.  Many of the most common furnace problems can be avoided during an annual maintenance visit.

Technicians will check many of the following items on a furnace maintenance visit:

  • Inspect the flue piping for any damage, birds nests or any other restrictions that can cause a back-up of carbon monoxide inside the home.
  • Inspect all of the high limit switches and roll-out switches that shut down a furnace if there is an emergency.
  • Inspect the heat exchanger inside of the furnace to make sure no breeches have developed over the last season.

Not only are technicians checking for possible future mechanical failure points, but the technician is looking to protect your family from possible dangers with carbon monoxide.

Your heating and cooling system is a very large investment, and routine maintenance can help protect that investment from small problems leading to a large expense.


Replacing your air filter inside your heating and cooling system is the easiest, but most forgotten way to avoid most of the common HVAC problems.  Just like a car requires an oil change every 5,000 miles, your HVAC system requires a new air filter to operate correctly.

When an air filter gets dirty it restricts the amount of air flow thru the appliance.  This can cause overheating problems, extra stress on the blower motor and even causes your energy bill to rise.

We suggest to use a standard 1″ air filter that is pleated and has a firm border.  Some of the high efficiency air filters from 3m are great at catching allergens such as pet dander, mold and dust.  Pay particular attention to these 3m filters as they tend to get clogged quicker since they catch more particles.


Ignition problems can come from a number of causes.  A burned out thermocouple or hot surface ignitor, dirty flame sensor or a blown out pilot can cause a furnace to lockout on safety and not heat your home.

Sometimes the first step is to simply turn the furnace power off and let the board reset itself.  Then turn the furnace back on and see if the appliance lights.  If the furnace does not come back on call an HVAC technician as this type for problem is best solved by a certified professional.

Performing a homeowner DIY fix on natural gas and/or high voltage can be a very risky and dangerous task.


There are hundreds of different models of thermostats on the market today, but most fall into the category of programable or non-programable.

Most of the modern thermostats operate partly or primarily by batteries.  A dead giveaway that the batteries maybe dead is if the screen is very dim, or even blank.  Check to see if your thermostats has batteries and more importantly think about the last time you replaced them. This may do the trick!

Other thermostat problems that could be the culprit is the scheduling/timing is off.  Check the settings to see if the schedule has called for the thermostat to turn off the appliance.  You may have to google the model for an installers guide if you do not have the brochure.

After you have checked these two common thermostat problems and you are still unable to get the system functioning reach out to a professional HVAC tech for help.


Inside a heating and cooling system there are many moving mechanical parts, that over time can begin to wear out.  Belts and bearings are the most common parts that wear out if not properly tightened and lubricated during routine maintenance.

Symptoms of mechanical  wear and tear can easily be prevented and/or repaired proactively during regular maintenance visits.  Mechanical wear and tear always seems to show its ugly head during the hottest or coolest time of year when you HVAC system is operating under full load.


Furnaces naturally make some noise while they operate, but when you hear noises that are out of the normal it’s cause for concern and requires attention.  Squealing noise is the most common furnace noise and is caused by a bearing in the blower motor that is failing.  This sound will not go away and a new blower motor is required.  A booming or explosion noise is the most dangerous and is cause of immediate attention.  The boom can come from delayed ignition of natural gas, which sometimes is caused by a gas valve or combustion air problem.

If you are hearing booming noises coming from your furnace turn off the appliance immediately and call an HVAC professional.


The most common reason that a breaker trips on a furnace is due to a blower motor which is over working.  This can be an easy DIY fix if your filter is dirty.  The dirty filter is restricting the airflow and is causing the blower to over amp.  Simply change the filter in the furnace, then switch the breaker back on and most of the time this solves the problem.

Another reason that your breaker or fuse has been tripped is a power surge.  This is especially true during the summer time when a thunderstorm has gone thru.  The electrical disturbance can cause either a spike or drop in voltage that results in a breaker tripping or fuse blowing.

The worst senerio is when your breaker trips on your air conditioner.  This almost always is a sign of a compressor failure or burn-out.  If this is the case I am sorry to tell you but you are in the market for a new air conditioner.  The breaker tripping was merely a result of a catastrophic failure of the compressor and it caused a dead short.

Best way to fix your common HVAC problems

Without a doubt the best way to fix your common HVAC problems is simply to hire a professional.  Although this may cost you a few hundred dollars, the repair will come with some sort of guarantee.  We wrote an article about what to look for in hiring a HVAC Contractor and you can read it here.

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