AC Troubleshooting Tips

Keep Your AC Unit Running Smoothly in Denver, CO 

As Denver’s trusted HVAC experts at Squeak’s Plumbing, Heating & Air, we’ve been serving Denver, Boulder, Lafayette, and surrounding areas since 2005. Our founder, Larry Benavidez—a licensed master plumber and HVAC technician with over 20 years of hands-on experience—has helped thousands of homeowners avoid costly breakdowns and extend the life of their air conditioning systems. In this guide, we’ll share proven troubleshooting tips based on real-world service calls from our team. These insights draw from industry best practices endorsed by organizations like the Air Conditioning Contractors of America (ACCA) and ENERGY STAR guidelines, empowering you to diagnose and resolve common AC issues quickly and safely.

Common AC Problems Homeowners Face

1. Low or no cooling
2. Higher than usual energy bills
3. Odd noises, vibrations, or smells
4. Water leakage or ice formation
5. AC not turning on or short‐cycling

With Denver’s dry heat summer’s and high-altitude challenges, proactive AC maintenance is key. Remember, while these DIY steps can prevent minor problems, complex issues like refrigerant leaks or electrical faults require professional intervention to avoid safety risks or voiding warranties. Ready to dive in? Let’s troubleshoot like pros.

1. Combat Dirty or Clogged Air Filters: The Silent Efficiency Killer

Why It Happens: In Colorado’s dusty environment—exacerbated by pollen from the Front Range and construction in growing suburbs like Lafayette—air filters capture airborne particles to protect your AC’s blower and coils. Over time (typically every 1-3 months), they clog, restricting airflow by up to 50%, according to ACCA research. This forces your system to overwork, spiking energy use by 15% or more.

Signs to Watch For:

• Reduced cool air from vents
• Ice buildup on refrigerant lines or evaporator coils
• Higher utility bills (e.g., an extra $50-100/month in peak summer)
• Leaking water from the indoor unit due to frozen coils

Expert Fix: Inspect your filter monthly during cooling season. Slide it out of the return air duct or furnace housing—most are 1-inch pleated fiberglass types (MERV 8-11 rating recommended for homes). Hold it to light: If you can’t see through it, replace it immediately. Pro tip from Larry: Opt for washable electrostatic filters for longevity in our arid climate; they last up to a year with proper cleaning.

Prevention Tip: Schedule bi-annual filter changes with an HVAC professional. Neglecting this can lead to compressor failure, costing $1,500-2,500 to repair.

2. Fix Incorrect Thermostat Settings: A Simple Seasonal Switch

Why It Happens: Thermostats are the “brain” of your HVAC system, signaling when to cycle on. With Colorado’s rapid weather shifts—from 90°F days to chilly evenings—it’s easy to overlook the mode during spring or fall transitions. A “HEAT” or “OFF” setting on a “COOL” day means your AC won’t engage, or worse, it runs inefficiently.

Signs to Watch For:

• Warm air blowing from vents despite the unit humming
• AC not turning on at all
• Inconsistent temperatures room-to-room

Expert Fix: Verify your thermostat is set to “COOL” and the fan to “AUTO.” Adjust to 78°F for optimal efficiency (per ENERGY STAR), saving up to 10% on bills. For smart thermostats like Nest or Ecobee, use the app’s diagnostics to rule out wiring issues. Larry’s advice: In high-altitude areas like Boulder (5,430 ft elevation), account for thinner air by calibrating 1-2°F lower than sea-level norms to maintain comfort.

Prevention Tip: Program seasonal reminders or integrate with our maintenance plans. Faulty thermostats cause 20% of service calls—don’t let it be you.

3. Clear Closed or Blocked Vents: Ensure Even Airflow Everywhere

Why It Happens: Furniture, rugs, or even forgotten dampers in unused guest rooms can obstruct vents, unbalancing your system’s pressure. This strains the blower motor and compressor, potentially shortening their lifespan by 30%, as noted in ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) studies.

Signs to Watch For:

• Uneven cooling (hot spots in certain rooms)
• Noisy operation or short cycling
• Rising energy costs from overcompensation

Expert Fix: Conduct a full-home walkthrough: Open all supply and return vents fully, and remove any blockages. Use a flashlight to check for dust buildup inside ducts—vacuum gently if accessible. In multi-story Denver homes, ensure basement returns aren’t covered by storage.

Prevention Tip: Map your vent locations on a home diagram for quick checks. Our pros use anemometers to measure airflow during tune-ups, identifying hidden restrictions early.

4. Clean Your Dirty Outdoor Unit: Rinse Away Debris for Peak Performance

Why It Happens: Colorado’s pine needles, cottonwood fluff, and urban pollen accumulate on condenser coils, reducing heat exchange efficiency by 20-30%. Without fins (the delicate coil surfaces) clearing heat, your AC pulls more amps, risking burnout.

Signs to Watch For:

• Warm exhaust air from the outdoor unit
• Poor overall cooling despite running non-stop
• Frequent cycling or unusual noises

Expert Fix: Turn off power at the breaker, then gently hose down the unit from the top (use low pressure to avoid bending fins). Clear debris from the base. For stubborn grime, apply coil cleaner (available at hardware stores) and rinse after 10 minutes. Larry warns: Never use a pressure washer— it can puncture coils, leading to $800+ leaks.

Prevention Tip: Trim nearby shrubs and schedule annual cleanings. In wildfire-prone areas like the foothills, this step prevents ash buildup too.

Why Early AC Troubleshooting Matters

An air conditioning system that’s acting up doesn’t only make things uncomfortable—it can also waste energy, shorten the life of your equipment, and lead to expensive repairs. As a locally owned and operated HVAC service in the Denver, CO area with over 20 years of experience handling thousands of residential cooling systems, we’ve seen how small issues left unchecked become big problems. In this guide, we’ll share tips both you can do safely at home, and signs to call the pros—so you get reliable performance and lower utility bills.

When to Call the Pros: Signs It’s Beyond DIY

While these tips resolve 70% of homeowner issues (based on our 18+ years of data), persistent problems like strange odors, grinding sounds, or no power demand expert eyes. Low refrigerant? That’s EPA-regulated and requires certified techs like ours. Delaying can escalate a $200 fix to a $5,000 replacement.

Some additional signs it’s time to call the HVAC experts at Squeak’s:

• You see ice forming on any part of the system beyond the evaporator coil
• Hissing or bubbling sounds suggest refrigerant leak
• Fan motor is making loud, grinding noises
• The unit repeatedly cycles on and off (short-cycling)
• Water leaking into the house or pooling around indoor unit
• The system is over 10-15 years old and major components like the compressor are failing

At Squeak’s, we prioritize transparent diagnostics—no upselling, just reliable results. Larry’s commitment to the community shines through our 24/7 emergency service and 100% satisfaction guarantee.

Maintenance Routines to Extend Your AC’s Lifespan

• Replace or clean air filters every 30-90 days (depending on use, pets, indoor air quality)
• Schedule yearly professional maintenance (clean coils, check refrigerant, inspect electrical components)
• Keep outdoor unit clear by trimming plants/shrubbery at least 2 feet all around
• Keep ducts clean and seal any leaks to improve efficiency
• Use ceiling fans to relieve load on AC on milder days