Commack HVAC Company is the full-service heating and cooling contractor for homes and businesses across Commack and Suffolk County. When the heat stops working on a January night, or the air conditioner quits on a humid July afternoon, one call gets the job moving. We handle everything from a routine seasonal tune-up to a full system replacement, and we are available any hour, any day of the year.
Calling an HVAC company doesn't have to be stressful, and we work to make sure it isn't. Whether you own a single-family home, manage a multi-unit rental, or run a commercial property, we scope the job on the call, confirm the price before anything is scheduled, and send someone who knows the work. We find the fault. We make the repair. We restore the comfort.
Call for a quote: (631) 623-9591
Every home's heating and cooling setup tells a different story, and we handle the full range of what comes up in this area. AC repair, air conditioner service, furnace repair and replacement, heat pump installation and service, full HVAC system installation and replacement, thermostat and smart-control upgrades, ductwork repair and sealing, indoor air quality and air filtration, and seasonal maintenance and tune-ups are all part of what we do.
A seasonal tune-up covers the components that matter: heat exchanger condition, refrigerant charge, airflow through the coil, and the controls that tell the system when to run. A smart thermostat upgrade can make a real difference in how consistently a home holds temperature, and we size and configure the control to match the equipment it runs. Ductwork that leaks at the joints loses conditioned air before it reaches the room, and sealing those connections is often the fix for uneven temperatures that a new thermostat alone won't solve.
For indoor air quality, we look at what the existing system can support: upgraded filtration, whole-home air purification, and ventilation adjustments that reduce humidity and stale air. HVAC work sized and installed the way the manual calls for means the system runs the way it was designed to, and that shows up in comfort and energy bills both.
No heat in the middle of winter. No cooling during a heat advisory. A furnace that won't turn on, an air conditioner blowing warm air, a heat pump short-cycling every few minutes. These are not situations that wait for a weekday morning, and we don't ask you to wait either.
We take emergency calls around the clock, nights, weekends, and holidays included. When you call, you reach someone who can walk through the symptoms with you, scope what the visit will cover, and get the job on the schedule. Common urgent calls we handle include a furnace not firing, a boiler losing pressure, an AC that has frozen up on the coil, or a heat pump that is running but not moving any heat.
HVAC service booked around your schedule means we work with what you have, not the other way around. If the system is down, call and we will work through what it takes to get the air running right.
Suffolk County's housing stock runs the full range, from post-war Cape Cods with cast-iron radiators to newer construction with high-efficiency heat pumps. Oil heat is still common across Long Island, older homes often have no ductwork at all, and the coastal humidity makes summer cooling a genuine concern rather than a seasonal afterthought. Systems like yours are familiar ground in these neighborhoods. The three services below come up constantly in this area, and we handle each one as a specialty rather than an exception.
A hydronic heating system circulates hot water through baseboard radiators or radiant floor loops to heat the living space. It is a different job from forced-air furnace work, and it requires knowing the equipment: the heat exchanger, the circulator pump, the expansion tank, the zone valves, and the controls that coordinate them. Boilers are common in Commack and across Long Island's older neighborhoods, and the symptoms that bring us out include a boiler that won't fire, no heat in one zone while others run fine, pressure that keeps dropping, or a system that bangs and knocks through the pipes.
We handle boiler repair, boiler service, and boiler replacement. When a boiler is past its useful range and a replacement makes more sense than another repair, we size the new unit to the actual heat load of the house. Permits handled where the job needs them, so the work is done to the standard the local inspectors enforce.
The Northeast runs on oil heat more than anywhere else in the country, and Long Island is no exception. Converting away from oil is one of the most common equipment decisions homeowners in this area are working through right now, and the options have expanded considerably. On the equipment side, a conversion means removing the existing oil furnace or boiler and installing a gas furnace, a heat pump, or a hybrid system that pairs a heat pump with a gas backup for the coldest days.
We handle the heating and cooling equipment side of the conversion. We size the replacement unit to the home, handle the installation, and make sure the new system integrates with the existing distribution, whether that is ductwork, hydronic baseboard, or a new ductless setup. Heat pump installation on Long Island makes particular sense given the region's push toward electrification, and a properly sized heat pump handles both heating and cooling from a single system. Call us and we'll walk you through your options.
Many homes in Commack were built without central ductwork, and adding ducts to a finished space is often more disruptive than it is worth. A ductless mini-split solves that problem directly. An outdoor compressor connects to one or more indoor air handlers mounted on the wall or ceiling, delivering heating and cooling to the room without touching the walls or ceilings of the rest of the house.
Mini-splits work well for finished basements, room additions, converted attics, and older homes where a window unit has been the only option. Each air handler operates independently, so a room that runs hot in summer and cold in winter can be dialed in without affecting the rest of the house. We handle mini-split installation, mini-split repair, and service on existing ductless systems. Reach out and we'll work out what it needs.
For homeowners, the questions that come up most often involve system replacement decisions, what a tune-up actually covers, and whether a smart thermostat upgrade is worth doing before or after a full system replacement. We answer those questions on the call, without pressure, so you can make a decision that fits the house and the budget.
For property managers and landlords, the priority is keeping units comfortable and minimizing the time a system is down. We coordinate multi-unit work, handle commercial heating and cooling repair, and understand that a tenant without heat or AC is a problem that needs a same-day answer, not a scheduled estimate. Commercial clients across Suffolk County work with us for the same reason residential customers do: the job gets scoped before it gets started, and the price is confirmed before anyone shows up.
For homeowners and property managers who want it done right, the call is where it starts. When you reach us, you get someone who knows the trade and can talk through what the system is doing, what it is likely to need, and what the visit will cover. The system is checked before parts are quoted, so you are not paying for a component that turns out not to be the problem.
No pressure and no gimmicks, just straight HVAC answers. The price is confirmed before we schedule, and what the visit covers is settled on the call. If the job turns out to need more than the initial scope, that conversation happens before the work does, not after. A price agreed before each visit. Clear scheduling each visit. Code-compliant every time.
We serve Commack as our primary area and work throughout Suffolk County. Nearby towns we cover regularly include Smithtown, Hauppauge, Kings Park, Northport, Elwood, Huntington, and Dix Hills. If you are in the surrounding area and unsure whether we cover your address, call and ask. We are available any hour, any day, and that applies to new calls and existing customers alike.
Common signs include a system that runs constantly without reaching the set temperature, one that short-cycles every few minutes, refrigerant leaks visible as ice on the coil or water pooling under the indoor unit, and energy bills that have climbed without a clear reason. Unusual sounds from the compressor or air handler are also worth paying attention to, particularly grinding, rattling, or a high-pitched squeal. If the system is showing more than one of these at the same time, a diagnostic visit is the right next step. Age and repair history both factor into whether repair or replacement makes more sense.
A boiler service call covers the components that keep a hydronic system running correctly: the heat exchanger, circulator pump, expansion tank, zone valves, and the pressure and temperature controls. If the system is losing pressure, banging through the pipes, or leaving one zone cold while others run fine, the technician traces the symptom to its source before recommending a repair. The repair cost is presented before any work is authorized. Boiler work is HVAC work, not plumbing, and we handle it as a regular part of the service we offer in this area.
A conversion starts with removing the existing oil-fired equipment and installing the replacement heating system in its place. We handle the equipment side: sizing the new unit to the home's heat load, installing it, and making sure it integrates correctly with the existing distribution, whether that is ductwork or hydronic baseboard. The gas-line run to the unit is plumbing work handled separately by a plumber. The quote covers the equipment and the installation, and it is confirmed before anything is scheduled.
A heat pump moves heat rather than generating it. In summer, it pulls heat out of the home and releases it outside, working the same way a central air conditioner does. In winter, it extracts heat from outdoor air and moves it inside, even when temperatures are well below freezing, depending on the equipment. A properly sized heat pump handles both functions from the same outdoor unit and indoor air handler, which is why it is a practical choice in a climate like Long Island's where both heating and cooling seasons are genuine.
A system that is losing efficiency works harder and runs longer to reach the same result. A refrigerant leak reduces the system's ability to move heat, so the compressor runs more. A clogged filter restricts airflow, which forces the blower to work against resistance. A heat exchanger that is not transferring heat correctly makes the burner run longer than it should. Each of those conditions shows up in the energy bill before it shows up as a complete failure, which is why a tune-up that catches them early saves more than the cost of the visit.
Leaky ducts push conditioned air into wall cavities, attic spaces, and crawl spaces instead of into the rooms where it belongs. The result is uneven temperatures, rooms that never quite reach the set point, and a system that runs longer than it should trying to compensate. Undersized ducts restrict airflow in a different way, creating pressure imbalances that show up as weak supply in some rooms and excess pressure in others. Both problems are diagnosable on a ductwork inspection, and sealing or resizing the affected sections is often a more cost-effective fix than replacing the equipment.
A spring AC tune-up covers coil cleaning, refrigerant level check, airflow verification, and thermostat calibration. A fall heating tune-up covers the heat exchanger, burner assembly, filter, and the safety controls that protect the system from running outside safe limits. The goal in both cases is to find a worn part or a developing problem while the system is still running, not after it stops on the hottest or coldest day of the year. Scheduling before the season means fewer emergency calls and a system that is ready when it is needed most.
Turn the system off at the thermostat if it is making unusual sounds, cycling rapidly, or showing signs of a refrigerant leak such as ice on the coil or water on the floor. Do not attempt to reset breakers repeatedly or bypass safety controls. Keep children and pets away from the equipment area, particularly the outdoor unit. If the home is losing heat in cold weather, close interior doors to hold warmth in the occupied rooms while you wait.
Someone who can provide access to the equipment and answer questions about how the system has been behaving should be present. For indoor equipment like a furnace or air handler, that means access to the mechanical room or utility space. For outdoor units, access to the side or rear of the property where the condenser sits. If the property is a rental and the owner will not be present, make sure the tenant knows the technician is coming and what they will need access to.
Clear a path to the furnace, air handler, and indoor unit, and move any stored items away from the access panel and the area around the equipment. For outdoor condensers, remove debris from around the unit and make sure there is a clear path from the entry point of the home to the equipment. If the system has floor or wall registers that are blocked by furniture, move those as well so airflow can be verified across the whole system.
Permits are handled where the job needs them, and the permit requirement is confirmed as part of the job scope before work begins. Requirements vary depending on the scope of the work and the municipality, and we confirm what applies to your address before scheduling. For replacement and installation jobs, the permit process is built into how the work is planned, not treated as an add-on after the fact.
Commack HVAC Company takes calls around the clock, every day of the year. Whether the system is down right now or you are planning ahead for a replacement or seasonal service, the next step is the same. We protect your home. We service your system. We earn the call.
Call for a quote, any hour, any day: (631) 623-9591
Every heating and cooling job in Commack comes with its own set of variables: the age of the equipment, how the home was built, and what the system has been doing before it stopped working right. The table below covers the services we handle across Suffolk County, who each one fits, and what is practical to know before you call. If a service you need is not listed or you are not sure which row fits your situation, a call gets you a straight answer.
| Service | Scope of Work | Common Needs | Helpful Details |
|---|---|---|---|
| Ductwork Repair & Sealing |
| Homes with uneven temperatures, rooms that never reach the set point, or rising energy bills without a clear cause | Leaky ducts push conditioned air into wall cavities and attic spaces. Sealing the connections is often the fix for comfort problems a new thermostat alone will not solve. |
| AC Repair & Service |
| Homes or businesses with a central AC that has stopped cooling or is running poorly | A system that runs constantly without reaching the set temperature often has a refrigerant or airflow problem, not a failing compressor. |
| Seasonal Maintenance & Tune-Ups |
| Homeowners who want to catch developing problems before the peak heating or cooling season | Scheduling a tune-up before the season means fewer emergency calls and a system that is ready when it is needed most. |
| Boiler & Hydronic Heating Service |
| Homes in Commack and across Long Island with hot-water baseboard or radiant floor heating | Boilers are common in this area's older housing stock. A system banging through the pipes or leaving one zone cold is a diagnostic visit, not a replacement conversation. |
| Indoor Air Quality & Air Filtration |
| Households dealing with dust, allergens, humidity imbalance, or stale air | Filters, airflow, and thermostat settings explain more faults than people expect. We check what the existing system can support before recommending any upgrade. |
| Ductless Mini-Split Installation |
| Homes without existing ductwork, room additions, finished basements, and converted attics | Each indoor air handler operates independently, so a room that runs hot in summer and cold in winter can be dialed in without affecting the rest of the house. |
| Emergency HVAC Service |
| Any situation where the system is completely down, nights, weekends, and holidays included | When you call, you reach someone who can walk through the symptoms, scope the visit, and get the job on the schedule. |
| Full System Installation & ReplacementMost Popular |
| Homeowners replacing an aging or failed system, or upgrading to a more efficient setup | A system's age and repair history both belong in the replacement decision. We scope the job on the call and confirm the price before anything is scheduled. |
| Heating & Furnace Repair |
| Any home with a forced-air furnace that has stopped firing, is short-cycling, or is producing uneven heat | A furnace that runs briefly and then shuts off is often tripping a safety limit, which points to airflow or heat exchanger issues worth catching early. |
| Heat Pump Repair & Service |
| Homes with a heat pump that is not heating or cooling effectively, or that is short-cycling | A heat pump that blows cool air in heating mode often has a reversing valve fault, not a refrigerant problem. |
| Oil-to-Gas & Heat-Pump Conversion |
| Long Island homeowners moving away from oil heat and weighing gas, heat pump, or hybrid options | We handle the heating and cooling equipment side of the conversion. The gas-line run is plumbing work handled separately by a plumber. |
| Thermostat Installation & Smart Controls |
| Homeowners who want better temperature control or are upgrading before or after a system replacement | A smart thermostat configured to match the equipment it runs makes a measurable difference in how consistently a home holds temperature. |
How often should a heating or cooling system be serviced, and does it matter which season?
A good baseline is once a year for a system that handles only heating or only cooling, and twice a year for a heat pump that runs year-round. For a forced-air furnace or boiler, a fall service visit catches developing problems before the heating season starts. For a central air conditioner, a spring visit before the first hot stretch is the right time. Getting on the schedule before the peak season also means the work gets done without competing with emergency calls.
What does it mean when one room is always hotter or colder than the rest of the house?
Uneven temperatures usually trace back to one of three things: a duct that is leaking, undersized, or blocked before it reaches that room, a zone valve or damper that is not opening fully, or an air handler that is not moving enough airflow for the square footage it serves. A duct inspection and airflow check are the right starting point. In some cases the fix is sealing or resizing a duct run. In others, a ductless air handler added to the problem room is the more practical answer.
What does it mean when the system makes a banging, grinding, or squealing noise?
A banging sound from a boiler usually points to water hammer or air trapped in the lines. A grinding noise from a furnace or air handler often means a blower motor bearing is worn. A high-pitched squeal from an outdoor AC unit or heat pump can indicate a failing compressor or a refrigerant pressure issue. None of these sounds are normal operation, and running the system while they continue tends to turn a repair into a replacement. A diagnostic visit identifies the source before the problem gets further along.
System Checked Before Parts Are Quoted
We diagnose the system before recommending a repair, so you are not paying for a component that turns out not to be the problem. The repair cost is presented before any work is authorized.
How does a dirty filter or coil affect how the system runs?
A clogged filter restricts airflow across the coil, which forces the blower to work harder and can cause the coil to ice over. A dirty evaporator or condenser coil reduces the system's ability to transfer heat, so it runs longer cycles to reach the same result. Both conditions show up in energy bills before they show up as a breakdown. Replacing the filter regularly and scheduling a coil cleaning as part of a tune-up are the two simplest things that keep a system running the way it was designed to.
What causes a system to short-cycle, and is it something to address right away?
Short-cycling means the system starts, runs for a minute or two, shuts off, and then restarts. The most common causes are an oversized system that satisfies the thermostat too quickly, a refrigerant charge that is off, a dirty coil or filter restricting airflow, or a safety control tripping because the system is running outside its safe operating range. Short-cycling puts extra wear on the compressor and other components, so it is worth diagnosing rather than waiting to see if it clears on its own.
Is older equipment worth repairing, or does it make more sense to replace it?
The answer depends on the age of the equipment, the cost of the repair, and the repair history. A system that is 15 years old and needs a compressor replacement is usually a replacement conversation, because the compressor cost approaches or exceeds what a new system would cost, and the rest of the equipment is still aging. A system that is 8 years old with a failed capacitor or a worn contactor is a straightforward repair. We scope the job on the call, explain what we find, and give you the information to make the decision that fits the house and the budget.
Emergency No-Heat and No-Cool Calls Handled
We take calls around the clock, nights, weekends, and holidays included. When the system is down and the heat or cooling cannot wait, the call gets the job on the schedule.
What does choosing between a furnace and a heat pump actually involve?
A furnace burns fuel, generates heat, and moves it through ductwork. A heat pump moves heat from outdoor air into the home in winter and reverses the process in summer, handling both heating and cooling from a single system. In a climate like Long Island's, where both heating and cooling seasons are genuine, a heat pump covers both without a separate AC unit. In the coldest stretches of a Suffolk County winter, a heat pump that is sized for the climate handles the load well, and a hybrid setup that pairs a heat pump with a gas backup is an option for homeowners who want additional coverage on the coldest days. We walk through the tradeoffs on the call based on the home's existing distribution and how it is currently heated.
How does a smart thermostat or control upgrade actually work, and what does the installation involve?
A smart thermostat replaces the existing wall control and connects to the heating and cooling equipment through the same low-voltage wiring. The installation covers confirming compatibility with the equipment, running any additional wiring if the existing setup does not include a common wire, mounting and wiring the new control, and configuring it to match the system's operating parameters. We walk through the settings before we leave so the control is actually set up to run the system the way the household uses it, not left on factory defaults.
Code-Compliant Work on Every Job
Permits are handled where the job needs them, and the permit requirement is confirmed as part of the scope before work begins. HVAC work installed the way the manual calls for is the standard on every visit.
When does it make sense to call a technician rather than attempting a fix yourself?
Replacing a filter, resetting a tripped circuit breaker once, or adjusting thermostat settings are reasonable starting points before calling. Anything beyond that, including refrigerant handling, heat exchanger inspection, electrical controls, or gas-fired equipment, is work that requires the right tools and knowledge to do safely and correctly. A repair that goes wrong on a furnace heat exchanger or a refrigerant line is a more expensive problem than the original fault. If the system is not responding after basic checks, a diagnostic call is the right next step.
How is an emergency no-heat or no-cool call handled differently from a scheduled visit?
We take emergency calls around the clock, any day of the year. When you call about a system that is completely down, the call covers what the system is doing, what the equipment is, and what the visit will include. The goal is to get someone out as quickly as the schedule allows. The diagnostic process on an emergency visit is the same as on a scheduled one: the system is checked before parts are quoted, and the repair cost is presented before any work is authorized. If the system cannot be repaired on the first visit, we explain what the next step is before we leave.
What signs point to a failing compressor or blower motor?
A failing compressor often shows up as a system that runs but does not cool or heat effectively, a hard start where the outdoor unit struggles to turn on, or a tripped breaker that keeps returning. A failing blower motor typically produces reduced airflow from the registers, a grinding or humming noise from the air handler, or a system that heats or cools at the equipment but does not distribute it through the home. Both components are diagnosable on a service call, and the repair decision depends on the age of the equipment and the cost of the component relative to a replacement.
Call us at (631) 623-9591 any hour, any day, and we will walk you through what the system needs and what the visit will cover.
(631) 623-9591