Before calling in an HVAC tech, try these troubleshooting tips. You may be able to fix the issue yourself and save some money along the way.
Welcome to New Homeowner Bootcamp, Family Handyman’s essential guide for navigating the challenges of homeownership, from little-known post-purchase tasks to money-saving maintenance and upgrades.
When your HVAC system stops working, your first instinct may be to reach for the phone. While large problems may merit the expertise of a professional, there are several things you can check first to do some troubleshooting yourself. If the issue appears to be one of the options on this list, then there’s good news! You can fix the problem yourself and save the money you would have spent on an HVAC technician for your home improvement budget (or just set it aside for a rainy day).
We spoke to HVAC experts to get some insight on what to look for and when it’s time to call in a professional. This way, you can go out with confidence, knowing that you’re well-equipped to keep your home at the right temperature. Additionally, you can rest assured that if you’re calling in help, it’s because the problem is serious.
Renting vs. Owning
If you’re renting your home, your property manager is likely in charge of scheduling big repairs. If you do end up needing to call in an HVAC tech, it’s a good idea to call your property manager to report any issues prior to calling a technician. It is not uncommon for technicians to arrive and be unable to make repairs without the owner’s consent.
Help Your System Out
You should help your system out as much as possible to prevent issues. When the temperature becomes unbearable outside, it’s a good idea to keep your curtains and blinds closed on the west side of your home since this is normally where the sun shines and traps heat within the home. Even something this small can keep your HVAC system operating smoothly and in top condition for many years.
You should also be aware of the limits of your system. On average, there will always be a 20-degree temperature difference between the inside of your property and the outside. For example, if it is 92 degrees outside, homeowners can expect their indoor temperature to be an average of 72 degrees. However, if it is significantly warmer such as 100+ degrees, the unit can experience difficulty in trying to cool the property. So while it may be warmer than you’d like on a particularly hot day, if you’re around 20 degrees cooler than the outside temperature, your system is probably still working.
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Air Filter
There are several HVAC issues that you can fix yourself. If your system isn’t working as expected, your first order of business should be checking your air filter and replacing it if necessary. If you have pets, carpet, or if your home is near fields or construction zones, it’s a good idea to have multiple filters on hand for convenient replacement. As a general rule, 1-in. filters should be changed every month, 2-in. filters should be changed every 2 months and 4 – 5-in. filters should be changed every 6 to 12 months.
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Circuit Breakers
It is not uncommon for power switches and breakers to be accidentally turned off when other appliances are being installed. If the air filter wasn’t the issue, you should check your circuit breaker to make sure the issue isn’t as simple as needing to turn a switch back on. Circuit breakers are typically located in the garage, although in some homes you can find them in the basement, hallway or storage room. Jeff Ault, a virtual HVAC expert with Frontdoor, says that “for outdoor units, check the disconnect near the condenser.”
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Vents
Vents are a sensitive component of any cooling and heating system. When HVAC troubleshooting, it’s important to check vents, ducts, and grills for blockage as that can be the leading factor of irregular air flow. Be sure to keep your furniture or plants at least two feet away from vents. Ault also notes that it’s important to “look for water around the indoor unit. A clogged condensate drain can cause leaks or shut the system off.”
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Power Outages
Before you call an HVAC tech, it is imperative to ensure you have power. If you’re having issues at a commercial property, it can be difficult to determine during business hours. However, this is often the main cause of irregular airflow. If your issues is in your home this is still a good step; a power outage is a straightforward explanation and generally doesn’t require expensive parts to repair.
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Check the Batteries
While there are a number of contributing factors such as blocked vents that can constrict air flow or lead to irreversible damages, the problem might be as simple as changing your batteries. This HVAC troubleshooting tip is often overlooked, but it’s one of the easiest fixes out there! If the thermostat is not lit, it is time to change the batteries.
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Check the Outside Unit
It’s easy to overlook your outside unit during checks of the HVAC system. However, it’s the central point for airflow into a building. HVAC technician Josh Mitchell has a handy list of things to look for on your unit: debris, bent fins or pooling water.
Debris such as leaves and branches can suffocate the entire unit as they are sucked onto the surface. If this is the issue, you can utilize a hose with a spray nozzle to rinse the unit. Start from the top to the bottom to remove excess debris once you’ve shut the power off. To prevent this from happening again, you should keep a minimum of a 3-feet radius of debris free area.
There’s an additional test too, one you can do by placing your hand over the vent. “If the air feels weak or warmer than it should be, it’s worth getting it checked before it gets worse.”
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Summer Frost
If you’re having problems with your cooling system in the summer, sometimes the cause is counterintuitive. Believe it or not, your pipes can actually freeze from overuse. If this turns out to be the problem, you’ll have to thaw out the system to resolve the problem. Block out some time for this; the process can take up two hours. Turn the unit off at the thermostat but turn the FAN on to efficiently thaw out the system. And to prevent the issue from happening going forward, be realistic about your settings. As tempting as it may be, do not set the thermostat below 70 degrees no matter how hot it gets outside! Otherwise you run the risk of freezing the system again.
Please note, when the system is thawed out and you turn it back on, it will continue cooling. However, it can potentially freeze over again. This could go on for a day or two. If this continues to persist for several days, it’s time to call in a certified HVAC tech as it can be an indication of further damage.
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Watch Out for Wires
Sometimes you can damage your HVAC system when clearing your property of weeds. Exercise caution when using a weed whacker around an outdoor unit because it can lead to clipped wires. Be on the lookout for wires that are out of place as you approach the unit. If you spot any, please contact your local certified HVAC tech.
FAQs
What are some early warning signs to look for?
Mitchell explains that there are a couple of places to look first before you go through the whole troubleshooting checklist: unusual power consumption, run time and uneven or mismatched cycles. “If the unit is pulling higher amps than expected, that often points to failing capacitors or motors, which tend to degrade slowly,” he says. “A healthy central AC compressor should draw about 8 to 10 amps. Anything above that, and I know I need to take a closer look.”
When it comes to runtime, a long period can point to sizing issues. Per Mitchell, “If the system is running for more than 20 minutes per cycle on a mild day (under 80°F), there’s a good chance the unit is either oversized or low on refrigerant. Both of those issues will shorten the lifespan of the system and increase wear on the compressor.”
After the runtime comes cycling issues. “If one room is 4 to 6 degrees warmer than the others, there might be a duct blockage or damper issue that’s often overlooked,” Mitchell explains. “Many people forget that flexible ducts can kink, especially in attics. About 30% of the energy in ducted systems is lost due to leaks or poor layout, according to the Department of Energy.”
Are there any troubleshooting areas that often get overlooked?
Mitchell says there are definitely troubleshooting areas that are overlooked. “One thing I don’t think enough people talk about is the importance of checking your line set insulation. If the suction line (the thicker copper pipe) is missing or damaged on the outside unit, you’re losing efficiency every time the system runs.” He warns that lost efficiency will show up on your energy bill, spiking it by about 10% a month.
When is it time to call in a professional?
Sometimes, even after troubleshooting, the issue persists. Mitchell says you should call in the professionals “if you’re hearing metal-on-metal sounds, smelling burnt wiring, or seeing frost on your indoor coils.” While it may be expensive, “it’s cheaper to call someone out for a $150 diagnostic than to wait and replace a $2,500 compressor.” As a general rule, “if it looks unsafe or feels like it’s getting worse by the day, don’t try to fix it on your own.”
Ault chimes in with a quick checklist:
- Breakers keep tripping.
- There’s a burning smell.
- You hear loud grinding, banging, or hissing.
- The system short cycles.
- High electric/gas bill, even if everything is working.
How do you know whether to replace or repair the HVAC system?
While your HVAC system should keep you cool for many years, it will eventually need to be replaced. If your system “is over 12 years old and you’re calling for service more than once a season, you might be throwing money at a system that’s already on its way out,” Mitchell says. According to him, “the average HVAC lifespan is about 15 to 20 years, but frequent minor breakdowns usually start showing up by year 12.”
About the Experts
- Josh Mitchell is an HVAC technician with Air Conditioner Lab.
- Jeff Ault is a Virtual HVAC Expert with Frontdoor, a service which connects homeowners with skilled tradespeople via virtual chat to walk through their home care and maintenance issues.
