COOLINGAC Installation & Replacement
Licensed AC installation & replacement on Long Island. Central air, ductless mini-splits & high-efficiency systems across Nassau & Suffolk County.
- CENTRAL AIR
- MINI-SPLITS
- HIGH-EFFICIENCY
- FREE ESTIMATES
Central air, ductless mini-splits and commercial cooling — installed right the first time and serviced fast when a Long Island heat wave hits. Licensed and insured across Nassau and Suffolk County, 24/7.
22+ YEARS ON LONG ISLANDLICENSED & INSURED · NASSAU & SUFFOLK
PLUMBING · HEATING · COOLING · CONTRACTING
Have An Emergency? We’re Available 24/7.
631-587-0085WE ANSWER EVERY CALLLong Island summers are humid as much as they are hot, and humidity is what most air conditioning fails to deal with. NJM installs, repairs and maintains central air, ductless mini-splits and commercial cooling for homes and businesses across both counties, with licensed technicians available around the clock through the season when a failure is not something you can sleep through.
We service every major brand and we size systems from the house rather than from the old unit’s label. Because the same licensed team handles heating, plumbing, gas and contracting, a cooling job that runs into ductwork, electrical or framing stays with us instead of stalling.
Master PlumberLicensed to pull permits
TASK 86/87Certified for gas work
Navien NSSFactory-trained on tankless22+ years on Long Island · Plumbing, heating, cooling, gas and contracting under one roof
One licensed team, one number to call, across Nassau and Suffolk County.
COOLINGLicensed AC installation & replacement on Long Island. Central air, ductless mini-splits & high-efficiency systems across Nassau & Suffolk County.
COOLINGFast AC repair & seasonal maintenance across Nassau & Suffolk County. Licensed HVAC techs, 24/7 emergency service, all major brands on Long Island.
COOLINGDuctless mini-split installation, repair & service for Long Island homes & businesses. Mitsubishi, Daikin & all major brands across Nassau & Suffolk.
COOLINGCommercial HVAC & cooling for Long Island businesses. Rooftop units, ductwork & 24/7 emergency service across Nassau & Suffolk County. 22+ years.
We don’t charge to quote a job. We do charge to find a problem nobody has identified yet. Which one you need — and what it costs — gets agreed on the phone, so nothing about the cost is a surprise on the doorstep.
You get the number on the phone, before anyone is dispatched, and it is what you are charged when the technician arrives. One rate across all four trades — plumbing, heating, cooling and gas.
A licensed, insured technician carrying the certifications the work needs, and the time to find what has actually failed — not a quick look and a guess.
A call-out advertised at almost nothing gets recovered once someone is standing in your basement. Get the number before anyone travels — from us, or from anyone else you call — and hold them to it when they arrive.
A boiler that fails in January is not a purchase anyone planned. Financing is available on the big-ticket work, so a system replacement does not have to come out of savings in one go.
Boiler, furnace and water heater replacement, a full air conditioning system, a whole-house repipe, sewer and water main work, and larger contracting jobs — kitchens, bathrooms, dormers and extensions.
At the estimate, before anything is scheduled. It is worth asking even if you think you will not need it, because knowing it is there changes what you are willing to consider fixing properly.
The price of the job. The quote is the quote whether you finance it or not — and on a straightforward repair it is usually not worth the paperwork. We will tell you which one you are looking at.
Three different answers to "my house is too hot", and the right one is decided by the building rather than by the equipment catalogue.
If the house already has usable ductwork, central air is normally the straightforward answer. One system, one thermostat, and the ducts are already in the walls. The question worth asking first is whether those ducts are actually up to it — a lot of Long Island duct runs were sized for a furnace and never for cooling, and pushing a new system through undersized returns produces a house that is still uneven and an owner who thinks they bought the wrong unit.
If there is no ductwork, ductless is usually better than the alternative of creating some. That is the case in a converted attic, an addition, a sunroom, a garage conversion, or an older house where running ducts would mean opening up finished space and losing ceiling height. One outdoor unit can carry several indoor heads on their own thermostats, and the same equipment heats as well as cools, which matters in a room the boiler never reached properly either.
For a commercial building the question is different again — rooftop package units and commercial splits are their own discipline, with their own access, curb and service requirements.
And sometimes the answer is not a system. If the complaint is that some rooms never cool while others freeze, or that the house feels cold and clammy rather than cold and dry, that is usually airflow or sizing rather than a failed unit. Replacing the equipment carries the problem across to the new one. We would rather diagnose that first and tell you the unit is fine, because a system replacement that does not fix the complaint is the most expensive way to be disappointed.




What it says on the coupon is what comes off the bill. Mention it when you call.
Load calculation first. A system that is too big cools the air without pulling the moisture out of it.
Code NJM-AC200Expires October 31, 2026See the details →$50 OffFifty dollars off the repair. We find what failed rather than topping it up and leaving.
Code NJM-ACREP50Expires October 31, 2026See the details →Maintenance PlansA system nobody services runs longer to do the same job, costs more doing it, and picks the first heat wave to stop. Preset or custom plans, for homes and for commercial buildings.
Code NJM-COOLPLANNo expiryAsk us →The building decides it, not the equipment. If you have usable ductwork, central air is normally the simpler answer, though the ducts are worth assessing first because plenty of Long Island duct runs were sized for heating and never for cooling. If you have no ductwork — an addition, a converted attic, a sunroom, or an older house where running ducts would mean opening up finished space — ductless is almost always the better answer than manufacturing ductwork to suit. We will tell you which one your house is, and we install both, so there is no incentive to steer you.
Probably not, and a bigger system will often make it worse. Uneven cooling is usually airflow — undersized or leaking ducts, blocked or insufficient returns, or a system fighting a badly balanced house. A cold but clammy house points at short cycling, which is what an oversized unit does. Both of those follow you to a new system if nobody diagnoses them, so we look at the airflow before quoting equipment. It is a cheaper conversation and quite often it is the whole answer.
Ours does, and that is the practical reason for using us. A cooling job runs into other trades more often than people expect — a new condenser needs the electrical to support it, a ductless head needs a penetration made good, a duct run through a finished ceiling needs framing and finishing afterward. When those sit with three separate companies the job stalls between them. Plumbing, heating, cooling, gas and contracting are all our own licensed team, so it stays one schedule and one company accountable.
That is the signature of an oversized system. It cools the air quickly and shuts off before it has pulled the humidity out, so the house feels clammy even at a low temperature. It can also be an airflow problem. Either way, more tonnage makes it worse rather than better. The fix is usually correct sizing or an airflow correction, both of which we handle — so it is worth a diagnosis before anyone sells you a bigger system.
Once a year, before the cooling season. A tune-up covers coil cleaning, refrigerant level, electrical connections, the condensate drain and airflow. The large majority of emergency calls we take in July trace back to something that would have been caught in spring.
Yes. Ductless mini-splits cool and heat individual rooms or zones with no ductwork at all, which is why they work so well in Long Island Capes, converted attics, additions and sunrooms. One outdoor unit can run several indoor heads.
Yes — rooftop units, split systems and ductwork for offices, restaurants, retail and multi-family properties across Nassau and Suffolk County, with the same 24/7 emergency response as our residential work.
All major brands, including Lennox, Trane, Carrier, Mitsubishi and Daikin. We work on whatever is already installed rather than pushing one manufacturer.
Central air systems generally run ten to fifteen years with regular maintenance, and window or wall units less. Age alone does not condemn a system — what changes the calculation is a major component failure, particularly the compressor.
Yes, for diagnostic visits — where something has failed and nobody knows why yet. It buys a licensed technician's time to find what has actually gone wrong, and it is one rate across plumbing, heating, cooling and gas. We give you the figure on the phone, before anyone is dispatched, and after-hours, weekend and holiday calls are quoted the same way. Estimates for new installations and renovation work are free.
Yes, without qualification — 24 hours a day, every day of the year, including nights, weekends and holidays. Call 631-587-0085. Regular office hours are Monday through Friday 7:00 AM to 6:00 PM and Saturday 7:00 AM to 5:00 PM.
Yes. This is the kind of job most people are not expecting to pay for all at once, particularly when the old one has just failed. Financing lets the work happen when it needs to rather than when the savings catch up. We finance through Synchrony, subject to credit approval. Ask when you call and we will go through the options for your job.
Yes, free and with no obligation, including for a new system. We look at the house and take the measurements sizing depends on before quoting anything. Requests through the form get a response within 24 hours.
Based in North Babylon, working across both counties — close enough to get there fast, local enough to know the housing stock and the permit offices.
Proudly serving all of Nassau and Suffolk County, with deep local roots near our North Babylon home base.
Get A Free Estimate5 out of 5 stars
NJM Mechanical Inc are awesome!!!!! Just Had a maintenance call / yearly service. Always professional prompt service. I had Neil as my service tech - great job.

5 out of 5 stars
Neil has handled all my A/C needs over the years. He's very communicative and open about service charges. He never steers you wrong

5 out of 5 stars
Neil Mazzella was able to add me to his emergency call list, same day service. Temps reached 100! Efficient, fixed the unit within a hour!


Free estimates with no obligation, 24/7 emergency response, and 22+ years serving homes and businesses across Nassau and Suffolk County.