Some issues are obvious — the system simply will not turn on. Others are more subtle but still require prompt attention to prevent a minor problem from becoming a major one. Here are the most important warning signs Ontario homeowners should never ignore:

The System Is Running But Not Cooling

If your ductless unit is powered on and the fan is running but the air coming out is warm or only slightly cool, the system has lost its ability to remove heat from the room. The most common causes are low refrigerant due to a leak, a dirty or iced-over evaporator coil, or a failed capacitor in the outdoor unit. This is a functional breakdown that requires immediate professional attention — running a refrigerant-starved system causes compressor damage that turns a $300 repair into a $2,000 one.

The System Will Not Turn On at All

A complete failure to power on points to an electrical issue — a tripped circuit breaker, a blown fuse, a failed control board, or a wiring fault. Do not repeatedly reset breakers and try to force the system back on without understanding why it tripped. Call a certified technician to diagnose the root cause before damage compounds.

Ice Is Forming on the Indoor or Outdoor Unit

Ice on your ductless system is not a sign that it is working too hard — it is a sign that something is wrong. Ice formation is most commonly caused by low refrigerant levels, a dirty evaporator coil restricting airflow, or a blocked air filter. If you see ice on your unit, turn the system off immediately and switch to fan-only mode to allow the ice to melt before calling for service. Running an iced-over system risks permanent compressor damage.

Water Is Leaking From the Indoor Unit

A small amount of condensation is normal during humid Ontario summers, but water dripping or pooling under your indoor unit is not. It almost always indicates a clogged condensate drain line — a quick repair on its own, but one that can cause significant water damage to walls, ceilings, and flooring if left unaddressed. This qualifies as an urgent repair call.

Loud, Unusual, or New Noises

A properly functioning ductless system operates near-silently. If you are hearing grinding, rattling, banging, hissing, or clicking that was not there before, something mechanical or electrical has changed. Rattling often indicates a loose fan blade or debris inside the unit. Hissing points toward a refrigerant leak. Grinding or squealing suggests a failing motor or bearing. None of these should be left to worsen.

Foul or Musty Odours From the Unit

A musty or mouldy smell coming from your indoor unit typically means mould or mildew has developed in the drain pan, on the evaporator coil, or inside the unit casing. Beyond the unpleasant odour, this is a health concern — mould spores are being distributed into your home's air with every cycle. A thorough cleaning and coil treatment is required.

The System Is Short-Cycling

Short cycling — where the system turns on, runs for only a minute or two, then shuts off and immediately restarts — is a sign of a control issue, a refrigerant problem, or a sensor fault. It is also extremely hard on the compressor, which takes the most electrical strain during startup. A system that short-cycles needs to be diagnosed and repaired before it causes a full compressor failure.

Here is a reference guide to the most frequent ductless system repair issues our technicians encounter across Ontario, with typical cost ranges and urgency guidance:

Note: Repair costs are estimates for the Ontario market and vary based on the brand, system age, parts availability, and specific fault. A diagnostic fee may apply and is often credited toward the repair. Protection plan holders pay no out-of-pocket repair costs for covered components.

We know that when your AC is down in the middle of a heat wave, the last thing you want to hear is that a technician will call you back during business hours. Here is exactly what happens when you call us at any hour:

• You reach a live person — not a voicemail, not an automated system. Our dispatch team answers around the clock.
• We take your address, a description of what the system is doing, and we immediately check technician availability in your area.
• We give you a realistic arrival window based on current dispatch load and your location — we do not promise a time we cannot keep.
• A certified technician arrives with a fully stocked service vehicle carrying the most common replacement parts for all major ductless brands.
• The technician performs a complete diagnostic to identify the root cause — not just the symptom — before recommending any repair.
• You are given a clear, written quote before any work begins. No surprise charges.
• If you are a protection plan holder, covered repairs proceed at no additional cost to you beyond any applicable service call fee.

You do not need to have purchased your system through Constant Home Comfort for us to repair it. Our certified technicians are trained and equipped to diagnose and repair ductless systems from all major manufacturers operating in the Ontario market, including:

• Daikin — including all Fit, Aurora, Quaternity, and Emura series models.
• GREE — including Sapphire, Vireo, Flexx, Livo, and Cascade series.
• Lennox — including all Mini-Split series models.
• Bosch — including Climate 5000 and 8000 series.
• Mitsubishi Electric — including all Mr. Slim and Hyper-Heating series.
• LG — including Art Cool, Dual Inverter, and multi-zone systems.
• Samsung — including Wind-Free and multi-zone mini-split systems.
• Carrier, Bryant, Fujitsu, Panasonic, and other brands operating in the Ontario market.

If your brand is not listed above, call us anyway — our team has experience across a wide range of systems and will let you know upfront if there are any limitations with your specific unit.

This is one of the most important questions our technicians help Ontario homeowners answer — and we always give an honest recommendation rather than defaulting to whichever option generates more revenue. Here is the framework we use:

Repair Is Usually the Right Choice When:

• The system is less than 8 to 10 years old and has been reasonably well maintained.
• The failed component is not the compressor — most other components are cost-effective to replace.
• The repair cost is less than 40 to 50 percent of what a comparable new system would cost installed.
• The system is still performing efficiently when operating — the issue is an isolated component failure.

Replacement Makes More Sense When:

• The system is 12 to 15 years or older and has had multiple repair events in the past two to three years.
• The compressor has failed — replacing a compressor on an aging system often costs nearly as much as a new installation, without the benefits of a new system warranty, improved efficiency, and modern technology.
• The repair estimate exceeds 50 percent of the cost of a new comparable system.
• The refrigerant type used in the system is R-22 (Freon), which has been phased out in Canada and is extremely expensive when available. Systems running R-22 refrigerant are strong replacement candidates.
• You want to take advantage of current rebate programs that apply to new high-efficiency systems — rebates that do not apply to repair scenarios.

Our technicians will give you a clear, honest comparison of repair cost versus replacement value at the time of diagnosis. If replacement is recommended, Constant Home Comfort can often have a new system installed the same day or within 24 hours, with financing options available to make the transition as easy as possible.

Understanding why ductless systems fail helps Ontario homeowners take steps to prevent the most common issues. The leading causes of ductless AC breakdowns our technicians encounter are:

Skipped Annual Maintenance

The single most preventable cause of ductless system failure is deferred maintenance. Dirty coils force the system to work harder, reducing efficiency and accelerating component wear. Clogged condensate drains cause water damage. Low refrigerant that could have been caught during a tune-up instead goes unnoticed until the compressor is damaged. Annual professional servicing catches all of these issues before they become failures.

Refrigerant Leaks

Refrigerant does not get consumed — if your system is low on refrigerant, there is a leak somewhere in the system. Leaks develop over time at connection points, in the coil, or in the line set. A system running low on refrigerant loses cooling capacity, overworks the compressor, and will eventually fail completely. Refrigerant leaks must be located, repaired, and the system recharged — simply adding refrigerant without fixing the leak is a temporary and wasteful measure.

Electrical Component Wear

Capacitors and contactors in the outdoor unit are high-wear components that fail with normal use, particularly under the sustained demand of Ontario summers. These are inexpensive parts but cause complete system shutdowns when they fail. Catching worn capacitors and contactors during annual maintenance is a low-cost way to avoid a mid-summer breakdown.

Clogged Air Filters and Coils

Indoor unit air filters should be cleaned every 4 to 6 weeks during active use — this is a simple task homeowners can do themselves. When filters are left dirty, airflow across the evaporator coil is restricted. This causes the coil to ice over, the system to lose cooling output, and eventually component damage from operating under strain. Dirty outdoor condenser coils cause the same problem from the other direction — the system cannot release heat effectively and overheats.

Age and Accumulated Wear

Most ductless systems are designed for 15 to 20 years of service with proper maintenance. Systems approaching or past the 12-year mark have accumulated significant component wear and are statistically more likely to require repair. For older systems, a protection plan or proactive replacement discussion makes sense.

While some failures are unavoidable, the majority of ductless AC repair calls in Ontario are preventable with basic care and professional annual servicing:

• Clean your indoor unit air filters every 4 to 6 weeks during the cooling season. Most indoor units have simple slide-out filters that rinse clean under a tap and can be reinstalled once dry.
• Keep the area around your outdoor condenser clear. Trim back vegetation to at least 12 inches on all sides, and remove any debris — leaves, grass clippings, or cottonwood seed — that accumulates around the unit.
• Do not run the system with ice forming on the unit. If you notice ice, switch to fan-only mode to melt it and call for service.
• Book a professional annual tune-up every spring before the cooling season begins. This is the single most impactful thing you can do to prevent mid-summer breakdowns.
• Enroll in a protection plan. Covered repairs cost you nothing beyond the plan premium, and the peace of mind through a full Ontario summer is genuinely valuable.

Constant Home Comfort provides 24/7 ductless air conditioner repair service throughout Ontario. Our dispatch network covers:

• Toronto and all Toronto neighbourhoods including North York, Etobicoke, Scarborough, and East York.
• The Greater Toronto Area including Mississauga, Brampton, Vaughan, Richmond Hill, Markham, Thornhill, Aurora, Newmarket, Stouffville, and Durham Region.
• Hamilton and surrounding communities.
• Ottawa and Kanata.
• Barrie and surrounding Simcoe County.
• Burlington, Oakville, and Halton Region.
• Waterloo Region including Kitchener and Cambridge.
• London and surrounding areas.
• Additional communities throughout Ontario — call us to confirm coverage in your area.

• Genuine 24/7 availability — a real person answers every call, any hour of the day or night.
• Fast dispatch — we do not make you wait days for a non-emergency appointment when your home is 35 degrees inside.
• Certified technicians trained across all major ductless brands — we carry the tools and parts to repair any system we encounter.
• Honest diagnostics — we tell you what is wrong, what it costs to fix, and whether repair or replacement makes more financial sense for your situation.
• Transparent pricing — you receive a written quote before any work begins, with no surprise charges on the invoice.
• Protection plan holders receive covered repairs at no out-of-pocket cost — just call and we come.
• If your system needs replacement, we can often install a new unit same-day or next-day with financing available.

How quickly can you send a technician for emergency ductless AC repair?

Response times vary based on your location and current dispatch load, but we prioritize emergency calls — particularly during heat advisories and extreme weather — and aim to have a technician on-site as quickly as operationally possible. Call us at 1 (888) 675-5907 and our dispatch team will give you an honest arrival window based on current availability.

Do you charge extra for after-hours or weekend emergency repairs?

After-hours and weekend service calls may carry a different service call rate than standard weekday appointments. Our dispatch team will be transparent about applicable fees when you call — there are no surprise charges. For protection plan holders, covered repairs are handled at no additional cost regardless of when you call.

Can you repair a ductless system that is not the brand you sell?

Yes. Our technicians are trained and equipped to service all major ductless brands in the Ontario market, including Mitsubishi, LG, Samsung, Fujitsu, Panasonic, Carrier, and others, in addition to the brands we sell and install. You do not need to have purchased your system through us to receive repair service.

My ductless AC is not cooling but it is running. What should I do?

Do not continue running the system at full demand if it is not cooling — this risks compressor damage if the issue is low refrigerant. Switch the system to fan-only mode to keep some airflow moving and call us for a diagnostic visit. The most common causes are low refrigerant, a dirty or iced coil, or a failed capacitor — all of which are repairable, provided the compressor has not yet been damaged.

Is it worth repairing a ductless AC that is 10 years old?

It depends on what needs to be repaired. A 10-year-old system with a failed capacitor or a clogged drain line is absolutely worth repairing — these are inexpensive fixes on a system that likely has years of life remaining. A 10-year-old system with a failed compressor is a closer call and warrants a direct comparison of repair cost versus new system installation. Our technicians will give you that comparison honestly.

What is the best way to avoid emergency ductless AC repairs?

Annual professional maintenance is the single most effective preventive measure. Cleaning the indoor air filters regularly — every 4 to 6 weeks during the cooling season — is the most impactful thing homeowners can do themselves. Enrolling in a protection plan removes the financial sting from repairs that still occur despite good maintenance.

Do not spend another night sweating through a breakdown that our team can fix today. Constant Home Comfort has certified technicians available around the clock, dispatched across Ontario, ready to diagnose and repair your ductless system fast.

Call 1 (888) 675-5907 right now for emergency dispatch, or use our online service request form for non-urgent repair bookings. We serve homeowners across Toronto, the GTA, Hamilton, Ottawa, Barrie, Burlington, Waterloo, London, and throughout Ontario.