M & D Plumbing Heating and Air Conditioning has been the go-to heating and cooling contractor for Commack homeowners and businesses since 2018. Locally owned and operated right here in Suffolk County, New York, we handle the full range of residential and commercial HVAC work, from a simple thermostat swap to a complete system replacement. Quick response. Straight pricing. No surprises at the unit.
We've served this area long enough to know what works, and what doesn't, when it comes to keeping homes and businesses comfortable through a Long Island winter or a humid July heat wave. When we started in 2018, the goal was simple: build a heating and cooling company that Commack families and local businesses could actually count on. Not a company that sends whoever is available, but a team that shows up prepared, explains what it found, and gets the work done right.
Eight years later, that focus hasn't changed. We've serviced and replaced systems all over these neighborhoods, and we've built our reputation one service call at a time. Customers reach a real local person when they call, someone who knows the area and can talk through the problem before a technician ever pulls up to the driveway. We offer no-pressure estimates, priced up front, so you always know what you're looking at before any work begins.
Give us a ring and we'll take care of it.
Our technicians know the homes and systems in this area, and we've worked on just about every configuration you'll find across Suffolk County. Whether your central air system is struggling to keep up on a hot afternoon, your furnace isn't firing on a cold morning, or you're thinking about upgrading to a more efficient heat pump, we handle it.
Our full service menu covers AC repair and service, furnace repair and service, heat pump installation and repair, full HVAC system replacement, ductwork repair and sealing, thermostat and smart-control installation, indoor air quality and air filtration, seasonal maintenance and tune-ups, ductless mini-split systems, and boiler and hydronic heating. Every job comes with clear communication from the first call to the final test, so you're never left guessing about what was done or why.
Call and we'll get the air running right.
Staying ahead of HVAC problems keeps your home comfortable, and that starts with having a team you can call for anything heating and cooling related. For homeowners, we cover the everyday work: AC tune-ups and repairs when the system isn't cooling the way it should, heating and furnace repairs when temperatures drop, heat pump service and installation, full system replacements when a unit has run its course, thermostat upgrades and smart-control installations, ductwork repairs and sealing, and indoor air quality improvements including filtration and ventilation.
We also handle emergency no-heat and no-cool calls. If your system goes down on a cold night or during a heat wave, you don't have to wait until the next business day. We're available when you need us, and we'll get someone to your door as quickly as possible.
What sets our technicians apart is straightforward: they treat commercial properties with the same care and attention they bring to a family home. For property managers, office managers, retail operators, and restaurant owners, HVAC downtime is a real problem. A broken rooftop unit in July or a heating failure in February affects your tenants, your customers, and your bottom line.
We handle commercial AC repair, commercial heating repair, ongoing commercial HVAC maintenance, and full system replacements for commercial properties across the area. We work efficiently to minimize disruption, and we give you upfront estimates so you can plan accordingly. We treat your property and its systems the way we would our own, and we communicate clearly at every step so there are no surprises when the invoice arrives.
Comfort problems don't wait, and neither do we. When your heat goes out in the middle of a January cold snap or your air conditioning stops working on one of those heavy Suffolk County summer days, you need a technician who can respond quickly, not one who schedules you a week out.
We offer emergency HVAC service and same-day scheduling options for Commack and the surrounding communities. Whether it's a furnace that won't fire, a heat pump that stopped responding, or a central air system that's blowing warm air, our technicians are ready to diagnose and address the problem fast. Quick to arrive. Careful with your home. Tidy when we leave.
We're ready to get your heating and cooling running again.
We've heard plenty of stories from customers who called another company, got a vague quote over the phone, and then faced a much larger number on the invoice after the job. That's not how we work.
When you call us for an estimate, we assess the job, explain what we found, and give you a clear number before any work begins. If the scope changes once a technician is on-site, we talk to you about it before moving forward. No hidden fees, no charges that appear out of nowhere, no pressure to approve work you didn't ask for.
HVAC repair costs, replacement costs, and installation costs vary depending on the system, the scope, and the equipment involved. We don't believe in one-size-fits-all pricing, but we do believe in telling you exactly what something will cost before we start. Call for a quote and we'll walk you through it honestly.
The quality of any HVAC service comes down to the people doing the work. Our technicians are trained and experienced across the full range of heating and cooling systems you'll find in homes and businesses across Long Island. That includes older oil-burning furnaces, modern heat pumps, ductless mini-split systems, central air setups, boiler and hydronic heating systems, and everything in between.
We've also handled oil-to-gas and heat-pump conversions as homeowners across the area look for more efficient alternatives to aging equipment. And for homes without existing ductwork, we install ductless mini-split systems that deliver zoned comfort without the disruption of a full duct installation.
Every technician we send to your property shows up prepared, communicates clearly about what they're doing, and leaves the space clean when the job is done.
We're not satisfied until you are. If something isn't right after a repair or installation, we want to know about it, and we'll make it right. That's not a policy written on paper somewhere; it's how we've operated since day one. Our reputation in Commack and across Suffolk County is built on repeat customers and referrals from neighbors, and we take that seriously on every single call.
If a job doesn't meet your expectations, call us. We'll come back and address it, no runaround.
We're based in Commack and serve customers throughout Suffolk County and the surrounding communities. Whether you're a few miles away or across the county, we can get a technician to your location.
We've serviced and replaced systems all over these neighborhoods, and we know the housing stock, the system types, and the seasonal demands that come with living on Long Island.
Communities we serve include:
If you're in the area and not sure whether we cover your location, just call. Chances are, we've already worked on a system near you.
We have been doing this work in Commack since 2018, which puts us at eight years in the community. We started with a simple goal: build a heating and cooling company that local families and businesses could actually count on, and that focus has not changed.
We are a locally owned, family-run business based right here in Commack. When you call, you reach a real local person who knows the area, not someone reading from a screen in another location.
We show up prepared, explain what we find, and give you clear pricing before any work begins. We treat your home and its system the way we would our own, which means honest feedback and no pressure to approve work you did not ask for.
We pick up the phone and work to get a technician scheduled as fast as the job requires. For emergencies, same-day response is often possible. For routine work, we typically have availability within a few days and work around your schedule where we can.
Our technicians know Long Island's housing stock, its climate, and the specific systems that run in homes and buildings throughout this part of New York. They arrive prepared, communicate clearly throughout the job, and leave the work site clean when they are done.
Yes. We are quick to arrive, careful with your home, and tidy when we leave. That is not just a saying. It reflects how every technician on our team is expected to handle a job site, from the first tool out of the truck to the last piece of packaging picked up.
M & D Plumbing Heating and Air Conditioning is Commack's locally owned, full-service heating and cooling contractor, ready to help homeowners and businesses across Suffolk County with everything from a quick repair to a complete system overhaul. When you call (631) 623-9591, you reach a real person who knows the area and can get you scheduled fast.
Whether you need emergency service today, a seasonal tune-up before the weather shifts, or an honest estimate on a new system, we're here to help. Quick response. Straight pricing. No surprises at the unit.
Call (631) 623-9591 to schedule service or request an estimate. We'll take care of the rest.
We handle the full range of residential and commercial heating and cooling work in Commack and across Suffolk County, from a same-day repair call to a full system replacement. Every job is performed by qualified HVAC technicians who know Long Island's homes, its climate, and the equipment that runs in them. The table below outlines what each service covers, who it fits best, and a practical note to help you decide where to start. Call us at (631) 623-9591 and we will walk you through the right option for your situation.
| System Service | What's Included | Best Suited For | Things to Know |
|---|---|---|---|
| Ductless Mini-Split Installation | Single-zone and multi-zone setups, Heating and cooling in one system, No ductwork required | Older homes without ducts, additions, sunrooms, or rooms that never reach the right temperature | Installation is typically cleaner and faster than retrofitting a full central system into an existing home |
| Emergency HVAC Service | Same-day and after-hours availability, No-heat and no-cool response, Honest diagnosis before any repair begins | Anyone whose heat or air conditioning has stopped working and cannot wait | We are available every day from 8:30 AM to 9:30 PM, including weekends |
| Heat Pump Repair and Service | Refrigerant leak checks, Airflow and control system testing, Heating and cooling mode diagnostics | Homes running a heat pump for year-round comfort on a single system | Heat pumps handle both seasons, so a problem in one mode often affects the other |
| Oil-to-Gas and Heat Pump Conversion | Removal of oil-fired equipment, Gas or heat pump system installation, Guidance on efficiency and operating costs | Homeowners ready to move off oil heat and reduce dependence on fuel deliveries | The Northeast carries more oil-heated homes than anywhere else in the country; conversion work is a regular part of what we do here |
| Thermostat and Smart-Control Installation | Programmable and smart thermostat installation, Wiring and settings configuration, Compatibility check with existing equipment | Anyone with an erratic system or who wants better control over comfort and energy use | A properly configured smart thermostat can meaningfully reduce energy use over time |
| Full System Installation and ReplacementMost Popular | Central AC and furnace replacement, Heat pump system installation, Energy-efficiency upgrade options | Homeowners whose system is aging, failing repeatedly, or no longer cost-effective to repair | We provide clear pricing before any work begins so you know the full cost up front |
| Boiler and Hydronic Heating Service | Hot-water baseboard and steam systems, Pressure and noise diagnostics, Radiant heat repair and maintenance | Older Long Island homes running boilers, radiators, or radiant floor heat | Many Suffolk County homes have boiler systems that have run for decades and benefit from regular service |
| Seasonal Maintenance and Tune-Ups | Spring and fall system tune-ups, Key component checks and safety confirmation, Pre-season performance review | Any homeowner or property manager who wants to avoid unexpected breakdowns | Systems that get regular maintenance last longer, break down less often, and cost less to operate |
| Heating and Furnace Repair | All makes and models, Blower and air handler service, Heat exchanger diagnostics | Any home or business that has lost heat or is getting inconsistent warmth | Emergency furnace repair is available when you cannot wait for a scheduled visit |
| Ductwork Repair and Sealing | Leak detection and sealing, Damaged section repair or replacement, Airflow balancing | Homes with uneven temperatures, high energy bills, or rooms that never feel right | Leaky ducts are one of the most common and overlooked causes of comfort and efficiency problems |
| AC Repair and Service | Diagnostic and refrigerant checks, Condenser and coil inspection, Airflow and cycling troubleshooting | Homeowners with a unit blowing warm air, cycling too often, or not keeping up | Same-day availability is often possible for urgent calls during the cooling season |
| Indoor Air Quality and Air Filtration | Whole-home air purifiers and scrubbers, Air filtration system installation, Whole-home humidifier installation | Families concerned about allergens, dust, dry air, or what the system is circulating | Long Island homes run their systems hard through humid summers and dry winters, making air quality equipment a practical upgrade |
How do I know whether to repair or replace my heating or cooling system?
Age and repair history are the two biggest factors. A system under ten years old that has been maintained and has a straightforward problem is usually worth repairing. When a system is older than fifteen years, has needed multiple repairs in recent seasons, or the repair cost approaches half the price of a replacement, replacement often makes more financial sense. We walk through both options with you honestly and give you clear pricing on each so you can make the call with full information.
What are the signs that my air conditioner or furnace may need to be replaced soon?
For an air conditioner, watch for rising energy bills without a change in usage, frequent repair calls in the same season, uneven cooling across the home, or a system that runs constantly without reaching the set temperature. For a furnace, warning signs include unusual noises, short cycling, cold spots in the home, or a heat exchanger that a technician has flagged as cracked or compromised. Neither list is exhaustive, but any of those patterns is worth a diagnostic visit.
How often should I schedule maintenance or a tune-up?
Once a year per system is the standard recommendation, and timing matters. For a central air system, a spring tune-up before the cooling season starts is ideal. For a furnace or boiler, a fall visit before you need heat is the right window. If you run a heat pump year-round, one visit in spring and one in fall covers both modes. Regular maintenance is the single most reliable way to avoid unexpected breakdowns and keep operating costs in check.
Transparent Upfront Pricing
We give you clear pricing before any work begins, whether it is a repair call or a full system replacement. No hidden charges, no surprise totals at the end of the job.
Why is one room in my home always hotter or colder than the rest?
Uneven temperatures usually point to one of a few causes: leaky or undersized ductwork, a zoning issue, a dirty filter restricting airflow, or equipment that is not sized correctly for the home. Ductless mini-splits can solve the problem in rooms that have never been comfortable, and duct sealing or repair often resolves it in homes with existing ductwork. A diagnostic visit gives us a clear picture of what is actually happening before we recommend a fix.
What does a seasonal tune-up actually cover?
A tune-up visit covers the key mechanical and electrical components of the system, confirms safe and efficient operation, checks refrigerant levels on cooling equipment, inspects the heat exchanger on a furnace, and tests controls and safety switches. We also look at the filter, the blower, and the coils. If something looks like it could become a problem before the next season, we flag it and explain what we found. The goal is to catch small issues before they turn into expensive repairs.
Can I get same-day service if my heat or air conditioning stops working?
Same-day availability is often possible, especially if you call early in the day. We offer emergency service for no-heat and no-cool situations throughout Commack and the surrounding area every day from 8:30 AM to 9:30 PM, including weekends. Call us at (631) 623-9591 and we will ask a few quick questions about the system and get a technician scheduled as fast as we can.
Same-Day and Emergency Availability
We are available every day from 8:30 AM to 9:30 PM, including weekends, and same-day service is often possible for urgent heating and cooling calls throughout Commack and Suffolk County.
What causes a system to short-cycle, and is it serious?
Short-cycling means the system turns on, runs briefly, shuts off, and repeats the cycle without completing a full heating or cooling run. It can be caused by an oversized system, a dirty filter blocking airflow, a refrigerant problem, a faulty thermostat, or a control board issue. It is worth addressing promptly because short-cycling puts extra wear on the compressor and other components and raises energy costs. A diagnostic visit identifies the root cause so the fix addresses the actual problem.
How do ductwork leaks affect my energy bills and comfort?
Leaky ducts allow conditioned air to escape into unconditioned spaces like attics, crawl spaces, or wall cavities before it ever reaches the rooms you are trying to heat or cool. The system works harder to compensate, energy bills go up, and some rooms never reach the right temperature. Sealing and repairing ductwork is one of the more cost-effective improvements a home can get, and the comfort difference is often noticeable right away.
Experienced With Older and Newer Systems
Long Island's housing stock ranges from decades-old boiler systems to newer heat pump installations, and our technicians are comfortable working on all of it.
What is involved in switching from oil heat to a heat pump or gas system?
The conversion involves removing the existing oil-fired equipment and installing a new gas furnace or heat pump system in its place. We handle the heating equipment side of the job. We walk you through the options based on your home's layout, existing ductwork, and what makes the most sense for your long-term operating costs. Many Suffolk County homeowners are making this move to reduce dependence on fuel deliveries and take advantage of more efficient technology.
Do I need to be home when the technician comes out?
For most service calls and installations, yes, an adult should be present. The technician needs access to the equipment, may need to ask questions about what the system has been doing, and will want to walk you through the findings and pricing before starting any work. If your situation is complicated, call us and we will work out the logistics together.
How does your pricing work, and will the estimate change once the technician arrives?
A technician assesses the system, explains what they found, and gives you clear pricing before any work begins. If the scope changes once we are on-site, we talk to you about it before moving forward. There are no hidden charges and no surprise totals at the end of a job. No-pressure estimates, priced up front, are how we handle every call, whether it is a repair visit or a full system replacement.
Call (631) 623-9591 and we will help you figure out exactly what your system needs and get you on the schedule.
(631) 623-9591