🧰 Introduction: Treat Your AC Right — and It’ll Treat You Right
Hey there — Tony Marino here. I’ve spent decades installing and repairing all kinds of air conditioning systems, and one thing I can tell you for sure: the better you maintain your AC, the better it will perform — period. Through-the-wall air conditioners, in particular, last a long time if you look after them properly.
Neglecting your unit can lead to clogged filters, frozen coils, strange noises, or leaky water — all of which can shorten its lifespan and send your energy bills skyrocketing.
In this article, I’m going to walk you through everything you need to know about keeping a through-the-wall AC running like new. I’ll also show you how to troubleshoot common issues so you can tackle them before they turn into costly repairs. Ready? Let’s jump in.
🧹 Routine Maintenance Tasks to Keep Efficiency High
Regular upkeep is the cornerstone of a healthy AC. Every month during the cooling season, do a few basic checks — they don’t take long and can save you money in the long run.
🔵 1. Clean or Replace the Filters
Your AC’s air filter traps dust, pet dander, and other debris. A clogged filter restricts airflow, forcing the unit to work harder and wasting electricity.
✅ Check it every 4–6 weeks during the cooling season — sooner if you have pets or live in a dusty area.
✅ Reusable filter? Rinse with warm water, dry thoroughly, then reinstall.
✅ Disposable filter? Replace with a new one if it looks dirty.
If you’d like more guidance on improving your home’s indoor air quality — including proper filter selection — check out this EPA article on improving indoor air quality.
🔵 2. Keep the Exterior Coil Clean
Your unit’s exterior coil needs good airflow to dump heat outside. Dirt, debris, and spiderwebs can clog it up.
✅ Inspect the exterior grille regularly.
✅ Use a soft brush or a garden hose with light water pressure to rinse debris off the coil.
✅ Trim any shrubs or plants at least two feet away.
And if you want to dive deeper into understanding your system’s components and why coil cleanliness matters, the U.S. Department of Energy’s AC maintenance guide is a helpful read.
🔵 3. Check the Drainage
Your through-the-wall AC unit removes a lot of moisture from the air. That water needs a clear path to drain outside — if it doesn’t, you’ll get water leaking into your home.
✅ Check the drain hole and pan for clogs.
✅ Use a pipe cleaner or compressed air to clear blockages.
✅ Ensure the unit tilts slightly outside to encourage drainage.
🔵 4. Inspect Insulation and Weatherstripping
Even a tiny gap around your unit can let in hot, humid air and drive up your energy bills.
✅ Check foam insulation around the edges of the wall sleeve.
✅ Replace weatherstripping if it’s brittle or cracked.
✅ Add a cover in the off-season if you live in a cold climate.
If you’d like more expert information on sealing up air leaks, check this article on energy efficiency and weatherization from ENERGY STAR.
🔧 Common Troubleshooting Issues — and What to Do About Them
Every homeowner eventually hears a strange noise or feels like the AC isn’t as cold as it used to be. Here are some common issues and the quick fixes you can try before calling a pro.
🧊 1. Unit Freezing Up
Symptoms: Ice on the coil, water dripping inside.
Causes:
❄️ Restricted airflow (dirty filters, blocked grilles)
❄️ Low refrigerant charge
❄️ Faulty thermostat
Quick Fixes:
✅ Turn the unit off and let it thaw.
✅ Check and clean the filter and exterior grille.
✅ Make sure the drain is clear.
If icing keeps happening despite your best efforts, you may have a refrigerant leak. Since handling refrigerants like R-32 requires certification and specialized tools, call a professional HVAC technician. The EPA’s guidelines on refrigerant safety explain why proper refrigerant handling is so important for safety and environmental protection.
🔊 2. Unusual Noises
Symptoms: Rattling, buzzing, or grinding noises during operation.
Possible Culprits:
⚙️ Loose sleeve or mounting screws
⚙️ Debris in the fan
⚙️ Failing motor bearings
Quick Fixes:
✅ Tighten any loose screws or brackets.
✅ Check for and remove debris around the fan.
✅ Run the unit and listen closely — if the noise is still there, it may require a professional bearing replacement.
💦 3. Water Leaks Inside
Causes:
💧 Improper tilt
💧 Clogged drain pan or hole
💧 Excessive humidity or refrigerant issue
Quick Fixes:
✅ Check that the unit is tilted slightly toward the outside.
✅ Clear any drain blockages with a pipe cleaner.
✅ If leaking continues, shut the unit off and call a pro.
🌡️ 4. AC Runs But Doesn’t Cool Properly
Causes:
❄️ Dirty filter
❄️ Insufficient refrigerant
❄️ Leaky wall sleeve allowing warm air infiltration
❄️ Dead compressor
Quick Fixes:
✅ Check the filter — clean or replace.
✅ Check weatherstripping around the unit and seal gaps.
✅ Make sure the thermostat is set to a low enough temperature.
If the unit still can’t keep up, you may have a refrigerant leak or compressor issue. A certified tech can test the refrigerant pressure and repair as needed.
🧰 When to Call a Professional
There’s a lot a homeowner can do to keep a unit in good shape. But some jobs need a pro — especially anything to do with refrigerant or internal electrical components.
Here’s when you need to pick up the phone:
✅ Repeated icing on the coil despite a clean filter and good airflow
✅ Strange electrical smells or burning odors
✅ Frequent tripping of the breaker
✅ Low refrigerant suspected — this must be handled under EPA 608 guidelines
✅ Dead compressor, which is a major repair that might mean it’s time for a new unit
And if you want to understand more about refrigerants like R-32 and their role in modern ACs, this article from AHRI on refrigerant safety and industry trends is a great read.
🧠 Proactive Tips to Extend the Life of Your AC
Beyond basic maintenance, here are a few extra pro-tips to help your unit last:
✅ Set a regular maintenance schedule. Write it on your calendar or set a phone reminder to check filters and drainage every month during the summer.
✅ Use a programmable thermostat. Let the AC cycle less when you’re not home.
✅ Consider an energy-efficient upgrade. If your unit is 10–15 years old, upgrading to a high-efficiency model (possibly with R-32 refrigerant) can pay for itself in energy savings.
✅ Cover the unit in winter. Use a breathable cover if you live in a cold climate to keep snow and debris out.
✅ Conclusion: A Well-Maintained AC is a Happy AC
When you take care of your through-the-wall air conditioner, it rewards you with years of quiet, efficient, trouble-free cooling. Maintenance doesn’t have to be complicated — most of the basics like filter checks and drainage are easy to do yourself.
And when you do need help with refrigerant checks, electrical repair, or other technical tasks, a trained HVAC pro can keep your unit safe and up to code. Keeping up with these simple habits will help your AC last longer, run more efficiently, and cost you less in the long run.
And if you ever need a new or replacement unit — or just want to browse the latest high-efficiency models — check out The Furnace Outlet’s full selection of through-the-wall air conditioners. We’ve got a great range of sizes and styles to suit any space.
✍️ About the Author
Tony Marino is a veteran HVAC technician with over 20 years of hands-on experience. Known for his no-nonsense advice and easy DIY guidance, Tony loves sharing practical HVAC knowledge so homeowners can stay comfortable and informed.
