Mini splits are one of the most efficient and popular ways to cool homes across Massachusetts — especially in older homes, additions, or when switching from oil or baseboard heat. But like any HVAC system, sometimes they stop cooling properly.

Whether you just had your system installed or you’ve had it for years, here are five common reasons your ductless mini split might not be cooling — and what you can do before calling Endless Energy for service.

✅ 1. Your Mini Split Is Set to the Wrong Mode

Let’s start simple: check your remote or thermostat settings. Mini splits can heat, cool, dehumidify, or run just the fan. If it’s set to:

  • “Heat”, it may actually blow warm air — even on a hot day.

  • “Dry” or “Fan”, it may feel like it’s running, but not actually cooling.

Fix it:
Set your unit to “Cool”, lower the temperature below room temp, and make sure the fan speed is turned up. Wait 5–10 minutes to see if the system starts blowing cold.

🧽 2. The Filter Is Dirty or Clogged

Mini split filters are usually washable and need to be cleaned every 1–2 months — especially during peak summer. If the filter is clogged with dust, it can restrict airflow and prevent the system from cooling efficiently (or at all).

Fix it:
Open the indoor unit’s front panel, remove the filter, and rinse it under warm water. Let it fully dry before reinstalling. If the unit starts cooling again afterward, problem solved.

❄️ 3. The Outdoor Unit Is Blocked or Overheating

Your mini split’s outdoor condenser needs to “breathe.” If it’s covered in leaves, mulch, cottonwood fluff, or debris, it may overheat and shut down cooling to protect itself.

Fix it:
Make sure there’s at least 18–24 inches of clearance around the unit. Remove any obstructions, and gently rinse the fins with a garden hose (no pressure washers!). If it still isn’t cooling, it might need a deeper coil cleaning.

⚠️ 4. The System Is Low on Refrigerant

Mini splits are closed systems, so they shouldn’t lose refrigerant unless there’s a leak (which can develop as systems get older). But if your system is several years old, or the installation wasn’t done properly, low refrigerant can cause:

  • Weak or no cooling

  • Ice buildup on indoor coils

  • Short cycling (turning on and off rapidly)

Fix it:
This one’s for the pros. Call Endless Energy — we’ll run diagnostics, check pressure levels, and repair the leak before recharging the system.

🔌 5. The System Needs a Reset or Is in “Defrost” Mode

Sometimes a power outage, surge, or even a system glitch can cause your mini split to freeze or get stuck in the wrong mode.

Fix it:
Try turning the system off at the breaker, waiting 60 seconds, and turning it back on. This can clear temporary glitches.

If your system is blowing lukewarm air on a cool day, it might be in defrost mode — a normal cycle where the outdoor unit clears ice. It usually resolves on its own within 5–10 minutes.

🧰 Still Not Cooling? Call Endless Energy.

If none of these steps solve the problem, we’re ready to help. Our HVAC techs are factory-trained on Mitsubishi, Fujitsu, and all major mini split brands — and we service systems whether we installed them or not.

We’ll:

  • Diagnose the issue fast

  • Check for refrigerant leaks, electrical problems, or bad sensors

  • Get your home cool again — without upsells or surprises

👉 Book your mini split repair or service now

Bonus Tip: Prevent Issues with a Tune-Up

Just like a car, your mini split runs better and lasts longer with regular care. Ask about Endless Energy’s $89 tune-up specials for first-time customers in Massachusetts — and our annual maintenance plans for ongoing savings and peace of mind.

Ready to get your AC tune-up? Give us a call at 508-501-9990 or schedule your maintenance directly online.