18 Simple HVAC Troubleshooting Tips You Can Do Yourself

HVAC Troubleshooting: Your First 5 Steps

Is your HVAC system blowing cool air in the winter — or no air at all? Is your air conditioning underperforming? Try these 5 simple DIY HVAC troubleshooting steps before anything else.

Step 1: Check for a Power Outage

Is there a power outage in your area you aren’t aware of? If your home has a backup generator, the power may have cycled between the grid and your generator — this can affect the overall function of your HVAC system.

Step 2: Check the Circuit Breaker

Open your circuit breaker panel to see if it’s flipped. Inspect the breaker for any blown fuses. If there aren’t any, flip the breaker and wait 5-10 seconds. Then, turn the power back on and check if your HVAC problem is corrected.

Step 3: Try an HVAC System Reset, Then Shut Off the Power

Each component of your HVAC system — furnace, air conditioner and heat pump — has its own dedicated reset method. Check your user manual for each malfunctioning component, and try a system reset.  

If the problem persists after your HVAC system reset, shut off the power before attempting any further fixes to avoid electrocution risk.

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Step 4: Check, Clean or Replace the Air Filter

Clogged air filters create significant strain on your HVAC system. They restrict proper airflow, limit heating and cooling capacity, and occasionally cause larger issues like overheated equipment and mechanical shut downs.

If your air filter hasn’t been cleaned in over a year, replace the air filter entirely. If it’s been under a year and there isn’t any visible damage, thoroughly clean the filter and return it to the component or vent.

Step 5: Check for Vent Blockages

After you clean your air filters, do the same with your vent grills and covers. Dust and grime buildup on your vent covers limits proper air flow and may be the source of your HVAC issue.

Schedule annual HVAC vent cleaning through HOMR, and we’ll do the rest.

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5 Easy Steps to DIY Furnace Repair

If your furnace isn’t working properly, try the following 5 DIY steps before calling a furnace company for a diagnostic check:

Step 1: Make Sure the Furnace Door is Closed Properly

Many homeowners miss this simple fix — your furnace is prevented from operating if the service door isn’t fully closed. Open the furnace door, check for any obstructions, then firmly close it. Turn your furnace on again — if this was the issue, it should return to normal function.

Step 2: Shut Off Power to Your Furnace

If you’ve recently experienced a power outage or surge, shut off power to your furnace. Wait 15-30 seconds, then switch the power back on. 

Step 3: Inspect the Burner Flames

With your furnace power turned on, activate the burners by adjusting your furnace thermostat upwards. Look at your burner flames after you turn up the thermostat.

Your burner flames should be blue in color and maintain a consistent level. If you see yellow flames, this indicates dirty burners in need of cleaning.

Don’t breathe directly on the flames — this may create a false yellow flame indication. Do not attempt to adjust or clean the burners yourself, this is a job for your furnace repair company.

New furnace installation costs around $4,600, and emergency furnace repair can run you close to $1,000. Learn 6 easy steps to save money on home furnace repair.

Step 4: Vacuum Out Your Furnace 

Shut off the power to your furnace, then shut off any gas intake as well. Vacuum your furnace thoroughly, and check for signs of black soot around your blowers. Eliminate as much dust as possible without tampering with the burners or other internal components of your furnace.

Use a shop vac with an extended hose attachment for this DIY project. 

Step 5: Change the Furnace Filter

Change the filter in your furnace at least once every 3 months. You don’t need overly expensive filters for your furnace — a simple fiberglass furnace filter performs well and costs under $5.

If the issue isn’t resolved after these 5 steps, call a furnace professional. We don’t recommend removing your furnace blower or cleaning your flame sensor without expert knowledge. 

Rather leave furnace work to the pros? Start here with a no-hassle project estimate.

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5 Quick DIY Thermostat Repair Checks

If your HVAC system is blowing out air at the wrong temperature, your thermostat is the first place to check. Follow these 5 thermostat troubleshooting steps before you call a pro — if they solve the problem, you’ll save $150-$200 on a diagnostic fee.

Step 1: Check the Power Source

If your thermostat has a display screen that’s off, that’s a sure sign the power to your thermostat isn’t working properly.

If the power switch is fully on but the power is off, take the cover off the thermostat. Replace the batteries (if your thermostat is battery powered).

Step 2: Make Sure Your Thermostat is Level

If your thermostat has a mercury bulb, it must sit fully level on the wall to operate properly. If your thermostat isn’t flush and level against the wall, make it level and see if that fixes the issue.

Step 3: Check the Thermostat Settings

Your thermostat may simply be adjusted to the wrong settings and/or the wrong timing. This is a common issue with smart and programmable thermostats, which can be a bit tricky to program correctly on the first try.

Verify that your thermostat is set to Heating mode if you want heat, and Cooling mode if you need air conditioning. You may need to manually override settings on your smart thermostat until it “learns” your patterns of behavior.

If your thermostat’s acting up, now’s a great time to consider the switch to a smart thermostat. Check out our rankings of the top 3 smart thermostat products.

Step 4: Check for Loose or Disconnected Wires

Thermostats are temperamental when it comes to wiring. Loose or even partially disconnected wires cause thermostats to stop working. Before you begin, always turn your thermostat power off at the breaker before checking wires.

Open your thermostat cover and inspect each terminal. Tighten the wire connections with a screwdriver  If you suspect any wire corrosion, we suggest calling an HVAC professional or electrician to handle the issue.

Step 5: Clean Your Thermostat

Dust, dirt and debris can cause thermostats to malfunction over time. Turn off power to your thermostat, then remove the cover and use compressed air to clean the thermostat. You may also use a small microfiber cloth or brush to remove dust.

Past this step, diagnostic thermostat repair involves using a multimeter to test the terminals and perform an overall transformer test. We suggest leaving these jobs to the pros.

Get your HVAC thermostat diagnostic done with a free quote through HOMR.

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3 DIY Air Conditioner Troubleshooting Tips

Step 1: Open Your AC Vents

The first step in DIY AC maintenance is to make sure all your air conditioner vents are fully open and unobstructed. If the vents in a single room are partially blocked, the warm air from that room will raise the temperature of your home.

Step 2: Check For Low Refrigerant Levels

Your air conditioning unit uses refrigerant to absorb warmth from the air and generate the cool air you desire. If your refrigerant levels are low, that generally indicates a refrigerant leak in your system — call an AC repair company to fully diagnose and fix this issue.

We live and work in Dallas — knowing a great AC repair service is crucial here. Read our updated buying guide and see which 2 AC companies we trust the most.

Step 3: Clean Your AC Condenser Unit

If your AC vents are fully open and the refrigerant levels are fine, try cleaning your AC condenser unit. Locate the condenser outside your home — it’s the large box that occasionally makes loud noises while your air conditioning is working.

Make sure all tall grass, plants and weeds are trimmed away from the condenser — these blockages cause ice to form on the condenser coils. Use a hose to clean the condenser by pointing it downwards along its exterior grills.

Cleaning your AC condenser can get grimy — reach out and we’ll handle it for you!

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7 Times You Should Call an HVAC Professional

When do you know it’s time to call an HVAC service? If you hear, smell or see something unusual around your furnace, boiler or AC system, call a pro immediately.

Here’s a list of 7 HVAC jobs that should be left to the professionals:

1. There’s no air blowing out of your vents.

Dirt, dust and debris can limit or restrict air flow from your vents. But if there’s no air coming out of your vents, that indicates a larger HVAC system issue. 

2. You’ve performed DIY HVAC fixes more than twice on the same unit.

If you’ve completed the DIY HVAC troubleshooting steps in this article more than twice on the same component, the issue requires the assistance of an HVAC repair service.

3. Your HVAC units are making odd noises.

If your HVAC system is making unusual sounds, that’s cause for concern — especially loud mechanical groans, straining noises or whirring. Do not attempt to diagnose or fix these noise-related issues yourself.

4. There’s a bad smell coming from your AC unit.

At best, that funky odor is an external smell that was pulled into your AC system. At worst, you’re dealing with metal corrosion, leaky freon or grinding motor parts. Don’t let the situation linger, as these issues can cause a fire, explosion or toxic fumes to enter your home.

Let’s help you make sure that odd noise or smell isn’t an emergency. Ask an expert!

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5. There are fluid leaks around your HVAC units.

Fluid leaks and pools around your HVAC units may not be water — they may be freon, which is extremely hazardous to touch. Do not attempt to fix or clean this yourself.

6. Your AC system is cycling on and off frequently.

Is your air conditioning system cycling on and off every few seconds? This is called ‘short cycling’. Short cycling has several potential causes, including dirty filters and coils, low refrigerant levels, frozen coils or a faulty compressor.

Short cycling causes your AC to experience bursts of maximum power usage, causing your energy bills to skyrocket. Call an AC repair company to address this issue ASAP.

7. Your HVAC system is over 15 years old.

The average home HVAC system has a lifespan of 15-20 years. If your system exhibits any of the above issues and is over 15 years old, it may be time to upgrade and replace your HVAC components.

Average HVAC Maintenance and Repair Costs

If you have to call an HVAC contractor to conduct repairs to your furnace, heat pump, air conditioning unit or vents, expect to pay the following for replacement parts (not including labor):

Table: Average HVAC Replacement Parts Costs

Expect to pay these average costs for HVAC repairs and labor:

Table: Average HVAC Repair Costs

Best HVAC Maintenance Schedule for Homeowners

Monthly HVAC Maintenance Schedule

Complete the quick tasks on this monthly HVAC maintenance schedule to ensure your system is running smoothly at all times. If nothing’s wrong with your system, you can check off this whole list in 15-20 minutes.

• Clean coils
• Clean fans
• Check vents
• Inspect AC refrigerant lines for leaks
• Check thermostat settings
• Visual furnace check for cracks and corrosion
• Ensure 2-3 feet of clear space around all HVAC system components

Seasonal HVAC Maintenance Schedule

Do the items on this list seasonally — once every 3 months, or once annually during the appropriate season.

• Replace air filters in furnace (every 3 months)
• Replace air filters in air conditioner (every 3 months)
• Routine air conditioner maintenance (every spring)
• Turn off water flow to your furnace (every summer)
• Turn on water flow to your furnace (every fall)
• Routine furnace maintenance (every fall)
• Replace your humidifier filter (every fall)

Prepping your home HVAC system for winter is vital to healthy air flow and proper home heating. Read our 15-step winter home maintenance checklist for best practices.

Annual HVAC Maintenance Schedule

Homeowners should complete these 3 HVAC maintenance tasks once per year.

• Replace air filters in heat pump (more often if needed, 2-3x per year for health concerns)
• Lubricate your AC motor and replace the fan belt if needed
• Schedule annual maintenance with an HVAC technician