Short answer: An air conditioner that sits idle for four to five months accumulates desert dust on internal components, develops potential capacitor weakness from disuse, and can become a nesting spot for insects and rodents. These issues compound silently — and the first time you'll notice is when you flip the system on during a 95-degree day and it doesn't respond the way you expect. A professional spring tune-up catches these problems before they become emergency repairs. Call The Cooling Company at (702) 567-0707 to schedule yours.
Key Takeaways
- Idle doesn't mean safe. Your outdoor unit has been exposed to five months of desert dust, wind-driven debris, and temperature swings — even though it hasn't been running.
- Capacitors weaken without use. The electrical components that start your compressor can degrade during extended inactivity, leading to hard-start failures when you need cooling most.
- Pests move in fast. Spiders, scorpions, and rodents treat dormant outdoor units as shelter. Nesting debris and chewed wiring cause short circuits and airflow blockages.
- Refrigerant micro-leaks go unnoticed. A slow leak that started last fall has had all winter to worsen. By spring, your system could be significantly low on charge.
- One tune-up catches all of it. A professional 25-point inspection before the first warm week eliminates guesswork and prevents the $800–$2,500 emergency calls we see every June.
The Quiet Months Aren't Quiet for Your AC
Here in Las Vegas, most homeowners shut off their air conditioning sometime in October. The nights cool down, the days become tolerable, and the thermostat switches to heat — or just stays off entirely during those mild stretches in November and December.
By the time February rolls around, your AC unit has been sitting dormant for roughly four to five months.
That might sound harmless. It's not running, so nothing is wearing out, right?
Not exactly. Your outdoor condenser unit is still exposed to everything the Mojave Desert throws at it: dust storms, windblown sand, construction debris (especially in rapidly developing neighborhoods like Skye Canyon, Cadence, and Inspirada), overnight temperature swings from 35 to 65 degrees, and the occasional hard rain that deposits mineral-laden water across the coil fins.
Your indoor components — the evaporator coil, blower motor, drain line, and air handler — are sitting in a dark, enclosed space where moisture can accumulate and dust settles layer by layer.
I've been working on HVAC systems in this valley for over 35 years. Every spring, I open up units that looked fine from the outside and find problems the homeowner had no idea were developing.
Here's what actually happens during those quiet months.
Desert Dust Coats Everything — Including What You Can't See
Las Vegas averages roughly 4.2 inches of rain per year. What we lack in moisture, we make up for in airborne particulates. Fine desert dust — a mix of caite, calcium carbonate, and silica — infiltrates your outdoor unit through the condenser grille openings even when the fan isn't spinning.
Over four to five months of inactivity, this dust:
Coats condenser coil fins. Even a thin layer of desert dust acts as an insulating blanket that reduces heat transfer efficiency. When the system fires up in spring, it has to work harder to reject heat, which means longer run cycles and higher electric bills from day one.
Clogs the condensate drain line. Dust that settles inside the air handler mixes with residual moisture in the drain pan. This forms a paste-like buildup that partially or fully blocks the drain. When cooling starts and condensation flows, backed-up water can overflow into ceilings, walls, or the air handler cabinet itself.
Settles on the blower wheel. Dust accumulation on blower wheel blades creates imbalance. An imbalanced blower vibrates, which wears bearings faster and reduces airflow. You might not hear it immediately — the vibration is subtle at first — but over a full summer of operation, it accelerates motor wear.
The fix is straightforward. A technician rinses the condenser coil, clears the drain line, and inspects the blower during a standard AC maintenance visit. Takes about 20 minutes of a 45-minute appointment. But if nobody checks, these issues stack up and compound across the entire cooling season.
Capacitors Don't Like Sitting Idle
Your air conditioner has two types of capacitors: a start capacitor that provides the initial jolt of energy to get the compressor spinning, and a run capacitor that sustains the motor during operation.
Capacitors are electrochemical components. They store and release electrical energy. When they operate regularly — charging and discharging through daily cooling cycles — they stay within their rated tolerance. But when they sit unused for months, the dielectric material inside can slowly degrade.
This isn't theoretical. It's one of the most common findings during spring tune-ups in Las Vegas. I'd estimate we flag capacitor weakness in one out of every five systems we inspect in March and April. The capacitor still technically works, but it's operating at 60–70% of its rated microfarad value instead of 95–100%.
What does that mean in practice?
A weak start capacitor makes the compressor struggle to turn on. You might hear a humming or clicking sound from the outdoor unit when the thermostat calls for cooling. The compressor tries to start, can't get the rotational momentum it needs, and either trips the thermal overload or blows a fuse. On a 105-degree afternoon, that's the difference between a $150 capacitor replacement and a $300+ emergency service call — assuming a technician is even available that day in peak season.
A weak run capacitor causes the compressor or fan motor to draw excessive amperage during operation. The motor overheats, efficiency drops, and the system cycles off on the high-pressure safety switch. You'll notice the house isn't reaching the set temperature, or the unit keeps turning on and off in short bursts.
Both scenarios are completely preventable with a capacitance test during a spring tune-up. The test takes 60 seconds with a multimeter, and a proactive replacement costs $120–$180 in parts and labor. Finding out the hard way in July costs three to four times that.
Pests Treat Idle Units as Real Estate
This one surprises homeowners the most, but it shouldn't. Your outdoor condenser unit is a metal box with openings, sitting in a yard in the desert. During the cooler months when it's not vibrating or generating heat, it becomes prime shelter for:
Black widows and brown recluses. They spin webs across the condenser coil interior and the electrical compartment. Webs don't just look bad — they trap debris that further clogs airflow, and spiders near electrical connections create a short-circuit risk.
Roof rats. Southern Nevada has a well-documented roof rat population. They'll chew through low-voltage thermostat wiring, gnaw on capacitor leads, and shred the insulation off refrigerant line sets. The damage can be invisible from outside the unit.
Scorpions. They squeeze through remarkably small gaps. A bark scorpion inside an electrical compartment won't damage the system by itself, but it's a safety hazard for the homeowner who opens the access panel without checking first — and the surprise sting is no joke.
Paper wasps. They build nests inside the top cover of the condenser where the fan motor housing creates a protected space. When the system turns on and the fan spins up, nest material gets thrown into the coil fins or jams the fan blade.
During every spring tune-up, we pull the electrical panel cover and visually inspect for nesting, webbing, and chew marks. About 15% of units in neighborhoods near open desert — Summerlin, Henderson foothills, Mountains Edge, North Las Vegas near the desert corridor — show some level of pest activity after winter.
Refrigerant Micro-Leaks Get Worse Over Time
Refrigerant doesn't get "used up" during normal operation. Your AC circulates the same charge of refrigerant in a sealed loop, absorbing heat indoors and releasing it outdoors. If the system was properly charged at installation, it should hold that charge for its entire lifespan.
But micro-leaks happen. A vibration-loosened flare fitting, a pinhole corrosion spot on the evaporator coil, a rubbed-through line where copper tubing contacts sheet metal — these tiny leaks release refrigerant so slowly that you might lose a pound or two over an entire year without noticing any performance change.
Here's the issue with idle time: during winter, the refrigerant in your system equalizes to a resting state. Pressures drop to ambient levels. This changes the stress points on fittings and joints. A fitting that was seeping at the rate of half a pound per year during active cooling might leak faster or slower at resting pressure — but it's still leaking.
By the time you fire up the system in spring, a leak that started as a minor inconvenience last August could have dropped your charge by two or three pounds. That's enough to cause:
- Reduced cooling capacity (the house takes longer to reach the set temperature)
- Ice formation on the evaporator coil (the coil gets too cold because there isn't enough refrigerant to absorb heat efficiently)
- Compressor overheating (low charge causes the compressor to work harder, which shortens its life)
A spring tune-up includes checking refrigerant pressures against manufacturer specifications. If the charge is low, the technician can locate the leak, repair it, and recharge to spec — before you're running the system 14 hours a day in July and the leak accelerates under full operating pressure.
Electrical Connections Corrode and Loosen
Your outdoor unit has dozens of electrical connections: wire terminals on the contactor, capacitor leads, fan motor plugs, compressor terminals, and the disconnect wiring. These connections are exposed to temperature cycling — expanding in afternoon heat, contracting in overnight cold — hundreds of times during winter.
Over months, this thermal cycling loosens terminal screws and causes micro-arcing at connection points. Corrosion from desert minerals and occasional moisture accelerates the process. A loose connection creates resistance, which generates localized heat, which causes further loosening. It's a slow-motion failure spiral.
The most common electrical failure we find during spring inspections is a pitted contactor. The contactor is the relay that switches your compressor and fan on when the thermostat signals for cooling. The contact points inside it develop pitting (tiny craters from previous arcing) that worsens over idle months as oxidation builds on the metal surfaces. A pitted contactor may still close the circuit, but it draws excessive amps, overheats, and can eventually weld itself shut — leaving your compressor running non-stop even when the thermostat isn't calling for cooling.
Contactor replacement is a $100–$150 repair during a scheduled tune-up. It's a $300+ emergency call when it fails at 2 a.m. and your system won't shut off.
The Air Filter Is Already Overdue
Most homeowners change their air filter based on the schedule recommended by the filter manufacturer — every 30, 60, or 90 days. But here's what happens in practice: you change the filter in September or October, the AC shuts off for the season, and you forget about the filter entirely until spring.
That filter has been sitting in your return air duct for four to five months. Even though the AC wasn't running, your furnace or heater likely was — pulling air through the same filter. And even during periods where neither system ran, dust settles through the ductwork by gravity and accumulates on the filter media.
By February, that filter is carrying five months of accumulated particulates. When you turn on the AC for the first time, it's pushing air through a partially clogged filter from day one. That means restricted airflow, higher static pressure, longer run times, and reduced indoor air quality before you've even started the cooling season.
The easiest thing you can do right now — before scheduling any professional service — is replace your air filter today. Walk to the return vent, pull out the old filter, check the size printed on the frame, and buy a fresh MERV 13 replacement. It costs $12–$18 and takes two minutes. If you do nothing else before summer, do this.
What a Spring Tune-Up Actually Catches
When we perform a spring AC tune-up, we're running through a 25-point inspection specifically designed to catch the problems that develop during idle months. Here's what we're checking and why:
| Inspection Point | What We're Looking For | Why It Matters |
|---|---|---|
| Capacitor test | Microfarad reading within 5% of rated value | Prevents hard-start failures |
| Contactor inspection | Pitting, arcing marks, loose terminals | Prevents overheating and weld-shut failures |
| Condenser coil rinse | Dust buildup, bent fins, debris | Restores heat transfer efficiency |
| Refrigerant pressure check | Suction and discharge pressures vs. spec | Identifies leaks before summer demand |
| Condensate drain flush | Blockages from dust-moisture paste | Prevents water damage indoors |
| Electrical connection tightening | Loose terminals from thermal cycling | Prevents arcing, overheating, fire risk |
| Pest inspection | Nesting, webbing, chewed wiring | Prevents short circuits and safety hazards |
| Thermostat calibration | Temperature accuracy within 1°F | Prevents overcooling and energy waste |
| Amp draw measurement | Compressor and fan motor amperage vs. nameplate | Identifies motors under stress before failure |
| Air filter check | MERV rating, condition, sizing | Ensures proper airflow from day one |
The full inspection takes 45 to 60 minutes. At the end, you get a written report of everything checked, anything flagged, and recommended repairs ranked by urgency. No surprises. No guesswork.
When to Schedule: The March Advantage
Here's what most Las Vegas homeowners don't realize: the best time to schedule AC maintenance isn't May. It's right now — late February through March.
Why? Three reasons:
Scheduling availability. In March, HVAC companies have open appointment slots throughout the week. By May, every company in the valley is booking two to three weeks out. By June, emergency calls dominate the schedule and routine maintenance gets pushed to whenever there's a cancellation.
Technician focus. A technician performing a tune-up in March has time to be thorough. The same technician in June is running five or six calls per day in extreme heat, juggling emergency repairs with scheduled maintenance. March appointments get unhurried, detailed attention.
Repair lead time. If the tune-up reveals a failing capacitor, worn contactor, or low refrigerant, you have weeks to schedule the repair at a convenient time and a standard rate. In June, those same repairs carry emergency premiums, and parts availability tightens as every contractor in town is ordering the same components.
The current promotion for a tune-up won't last into peak season. If you've been meaning to get this done, now is the time.
What You Can Do This Weekend (No Tools Required)
Before you even call for a professional tune-up, you can do a quick visual check of your system that takes 15 minutes:
Walk outside and look at your condenser unit. Is anything leaning against it? Are there weeds or debris piled around the base? Clear a two-foot perimeter on all sides.
Check the disconnect box (the small metal box on the wall next to the outdoor unit). Make sure the door closes flush and there are no signs of rust, ant trails, or water staining.
Go inside and locate your return air vent. Pull the filter. If it's gray, clogged, or you can't remember when you last changed it — replace it today.
Find your thermostat and switch it from "heat" to "cool." Set the temperature five degrees below the current indoor reading. Walk outside. Do you hear the outdoor unit start within two minutes? If yes, good sign. If not — or if you hear clicking, humming, or buzzing without the fan spinning — that's a call to make.
Look at the copper refrigerant lines running from the outdoor unit to the house. The larger insulated line (the suction line) should have intact foam insulation with no tears, cracks, or exposed copper. Damaged insulation wastes energy and allows condensation.
These five checks take 15 minutes and give you a baseline understanding of your system's condition. They don't replace a professional tune-up — but they help you have a more informed conversation when the technician arrives.
The Bottom Line
Your air conditioner has been sitting through a Las Vegas winter. That means desert dust on the coils, potential capacitor degradation, possible pest intrusion, slow refrigerant loss, and electrical connections that have been loosened by months of temperature cycling.
None of these problems announce themselves. They wait until you need cooling on the first 95-degree day and your system either underperforms, short-cycles, or doesn't start at all.
A spring tune-up — scheduled now, while appointment slots are wide open — catches every one of these issues in a single 45-minute visit. It's the difference between walking into summer with confidence and crossing your fingers.
Call (702) 567-0707 or book online to schedule your spring AC tune-up. We serve the entire Las Vegas Valley — Henderson, Summerlin, North Las Vegas, Green Valley, Enterprise, Southern Highlands, and everywhere in between.