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Commercial Rooftop HVAC Units (RTUs) for New York City & Long Island Buildings
The rooftop unit is the workhorse of commercial HVAC — and the equipment your building's comfort complaints, energy bill, and capital budget all trace back to. Com+ Mechanical repairs, replaces, and installs packaged rooftop units across retail, office, restaurant, warehouse, medical, and mixed-use buildings throughout New York City's five boroughs and Long Island, with every recommendation grounded in a real load calculation — never a rule-of-thumb guess.
Rooftop HVAC Unit Types & Configurations
Gas/electric packaged rooftop unit
The dominant configuration in commercial New York: an electric refrigeration circuit for cooling paired with a natural-gas furnace section for heating, in one cabinet. It's proven, parts-ubiquitous, and inexpensive to operate where gas is cheap. Its trade-off is on-site combustion — relevant for buildings tracking Local Law 97 emissions — and a gas train, venting, and combustion safety inspections that an all-electric unit doesn't carry.
All-electric and heat-pump rooftop units
A heat-pump RTU reverses its refrigeration cycle to heat the building from outdoor air, with electric-resistance backup for the coldest days. No gas line, no flue, no combustion — which removes that equipment from your LL97 emissions footprint entirely. Heat-pump RTUs have matured dramatically in cold-climate performance and are now the default specification for new commercial construction and conscientious replacements in the NYC metro.
Single-zone vs. multi-zone (VAV) configurations
A single-zone unit conditions one space with one thermostat — simple, common in small retail and restaurants. Multi-zone units (and single-zone units feeding a variable air volume, or VAV, system) serve several areas off one cabinet with zone dampers or reheat, trading simplicity for control. Zoning strategy is a design decision made before the unit is selected, not after — which is why it belongs in the assessment, not the installation.
Efficiency tiers: single-stage, two-stage, and variable-capacity
Baseline single-stage units run full-on or full-off; two-stage units modulate in steps; variable-capacity units (with variable-speed blowers and compressors) match output to load continuously. The efficiency payoff is real — most commercial buildings spend most of their runtime at part load — and it compounds across a fleet of units. We weigh the tier against your runtime, energy rates, and LL97 exposure rather than defaulting to first cost.
Economizer and ventilation equipment
Modern commercial RTUs include an economizer — motorized dampers that bring in cool outdoor air for free cooling when conditions allow — plus demand-controlled ventilation for occupancy-based outside air. A working economizer is one of the highest-ROI components in the cabinet; a seized actuator or failed sensor is also one of the most common and least noticed failures. Economizer function should be verified on every maintenance visit, not assumed.
Capacity, curb footprint, and rigging reality
RTUs run roughly 3 to 25+ tons per unit, and the practical constraints on any given roof — structural capacity, curb dimensions, crane access, and street logistics in NYC — shape what can actually be installed, not just what's on a spec sheet. The replacement that matches your existing curb footprint and lift path is often dramatically cheaper than the one that doesn't. Both belong in the scoping conversation.
What Is a Rooftop HVAC Unit (RTU)?
A rooftop unit — RTU, or packaged rooftop unit — is a self-contained HVAC system: one factory-assembled, weatherproofed cabinet holding the compressor, coils, blower, heating section, filters, and controls, mounted on the roof and ducted down into the space below. It cools, usually heats, and ventilates the building without occupying a square foot of leasable floor area. Capacities commonly run from about 3 tons to 25+ tons per unit, and larger buildings deploy a fleet of them — often one per zone, wing, or tenant. Gas/electric packages (electric cooling, gas heating) are the most common configuration, while all-electric heat-pump RTUs are increasingly specified as buildings pursue electrification under Local Law 97. For a component-by-component breakdown of what's inside the box, see our commercial rooftop unit guide — this resource is the decision hub: choosing, sizing, costing, and replacing them.
What This Rooftop Unit Resource Covers
Why Buildings Run on RTUs — and When Something Else Fits
Our Simple Process
From call to comfort in 6 easy steps
1. Rooftop assessment
We document the existing unit or units, curb dimensions and condition, roof access and rigging path, gas and electrical infrastructure, and controls landscape — before any equipment is discussed.
2. Load calculation
Cooling and heating loads are verified against your actual building envelope and usage — not matched blindly to the tonnage of a legacy unit that may have been wrong the day it was installed.
3. Options & efficiency analysis
We present configuration options (gas/electric vs. heat-pump), efficiency tiers (single-stage vs. variable-capacity), and lifecycle cost comparisons — including Local Law 97 emissions impact where it applies.
4. Proposal & scheduling
A fixed, itemized written proposal covering equipment, curb or curb-adapter work, rigging, tie-ins, controls, permits, and disposal — with lift and tie-in scheduling planned around your building's operating hours and tenants.
5. Rigging, installation & tie-ins
Crane set, curb adapter fabrication and installation, gas and electrical connections, duct transitions, and controls integration — executed by EPA 608-certified technicians with permits coordinated where required.
6. Commissioning & maintenance
Startup, refrigerant charge verification, airflow balancing, economizer function testing, and controls checkout — followed by an annual maintenance plan (2-4 visits) that protects efficiency, capacity, and warranty coverage.
Why Property Managers Call Com+ for Rooftop Units
Assessment-first, not catalog-first
Every recommendation starts with the roof, the curb, the loads, and the building — not a per-ton price sheet. If a like-for-like changeout is the right answer, we say so; if re-engineering the zoning saves you money long-term, we show you the math.
Occupied-building specialists
We work over occupied retail, office, and restaurant space routinely: lifts scheduled around operating hours, after-hours rigging when needed, certificates of insurance for managed properties, and tenant coordination that keeps complaints off your desk.
NYC logistics handled
Street occupancy and crane logistics, curb adapter fabrication, gas and electrical tie-ins, and permit coordination with licensed Professional Engineers are standard scope on our RTU projects — not surprises billed later.
One accountable contractor
Assessment, equipment, rigging, tie-ins, commissioning, and the maintenance plan that follows all sit with one company and one point of contact — no finger-pointing between the equipment vendor, the rigger, and the controls tech.
Transparent Pricing
No fees. No surprises. Just honest service.
Rooftop repair & assessment
For units worth saving: diagnostic assessment, component replacement (compressors, blower motors, controls, economizer actuators), refrigerant management, and gas-side repairs on gas/electric packages.
- Full diagnostic with written findings and repair-vs-replace recommendation
- OEM or approved components with warranty on parts and workmanship
- Economizer and controls repair and recalibration
- Honest recommendation when repair is throwing good money at a dying unit
Like-for-like replacement
Swapping an end-of-life unit for a matched modern replacement: same capacity and footprint philosophy, updated efficiency and refrigerant, minimal ductwork or zoning changes.
- Load-verified sizing (not blind tonnage matching)
- Curb reuse or curb adapter fabrication
- Crane rigging scoped before the lift is booked
- Startup, commissioning, and disposal of the old unit
Re-engineered / electrified replacement
Replacing aging gas/electric packages with heat-pump RTUs, re-zoning, or converting to VRF where the building's emissions targets and usage profile justify it — the Local Law 97 path.
- Local Law 97 emissions impact modeling before specification
- Zoning redesign and duct modification where it pays
- Electrical capacity and gas disconnection scope
- Phased execution across a fleet of units, building stays occupied
We do not publish flat per-ton or per-square-foot RTU prices — a number produced without a load calculation, curb assessment, and rigging review is the wrong number for your building. Request a rooftop assessment and we'll respond with a fixed, itemized proposal.
Own a Commercial Property?
Business+ plans start at $499/year — includes 2 rtu tune-ups, 10% off all services, and priority scheduling.
Equipment & Brands We Service
Factory-trained technicians for all major HVAC manufacturers
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Serving the New York City Metro Area
Commercial HVAC service for buildings across the five boroughs and nearby counties
Frequently Asked Questions
Get answers to common questions about our services
What is a rooftop HVAC unit (RTU)?
A rooftop unit (RTU) is a packaged, self-contained HVAC system — compressor, coils, blower, heating section, filters, and controls in one factory-assembled, weatherproofed cabinet — mounted on the roof and ducted down into the building. It cools, usually heats, and ventilates the space without occupying interior floor area, which is why it is the default HVAC choice for low-rise commercial buildings.
How much does a commercial rooftop HVAC unit cost?
Cost depends on far more than tonnage: the unit's configuration (gas/electric vs. heat-pump), efficiency tier, curb fit and condition, crane access and rigging path, gas and electrical infrastructure, controls scope, and occupied-building logistics. Two identical 10-ton changeouts in different buildings can land at very different totals. Com+ Mechanical scopes every replacement after an on-site assessment and issues a fixed, itemized proposal — no per-ton guesses.
How long do commercial rooftop HVAC units last?
Typically 15-20 years when properly maintained — and meaningfully less when maintenance is skipped. Salt-air exposure near the coast, economizer neglect, dirty coils, and oversized short-cycling units all shorten life. A well-maintained unit at year 18 is a replacement candidate; a neglected unit at year 12 usually already is.
Gas/electric RTU or heat-pump RTU — which is right for my building?
Gas/electric is proven and cheap to run where gas is cheap, but it carries on-site combustion that counts against Local Law 97 emissions. Heat-pump RTUs are fully electric, have matured in cold-climate performance, and remove that combustion from your emissions footprint. Com+ Mechanical models the LL97 impact and lifecycle cost for your building before recommending either — the right answer varies by gas rates, runtime, and emissions exposure.
What tonnage RTU does my building need?
There is no reliable rule of thumb — roughly 1 ton per 400-600 sq ft is a starting guess that is wrong often enough to be dangerous. Real requirements depend on envelope, occupancy, ventilation, equipment loads, and hours of use. Com+ Mechanical sizes every unit from an actual cooling and heating load calculation, which regularly un-sizes legacy units that were oversized (wasting money) or undersized (never keeping up) from day one.
Can the new RTU reuse the existing curb?
Sometimes. New units almost never match the old footprint exactly, so a custom curb adapter is usually fabricated to mate the new unit to the existing duct penetrations — that is normal and budgeted. But a curb that is corroded through or structurally compromised needs replacement, which adds roofing work. Com+ Mechanical assesses the curb during the rooftop visit so the proposal reflects it, rather than discovering it on install day.
Should I repair my rooftop unit or replace it?
As a working framework: units over 15 years old facing a compressor failure, units still running phased-out R-22 refrigerant, and units with recurring repair bills approaching a meaningful fraction of replacement cost are usually better replaced — modern efficiency, refrigerant, and warranty coverage beat patching a dying unit. Units under 10 years with a single component failure are usually worth repairing. Every diagnostic includes a written repair-vs-replace recommendation.
How disruptive is an RTU replacement to tenants?
Far less than most capital projects. A like-for-like changeout is typically a one-day crane set: the old unit comes off and the new one goes on, with tie-ins and startup the same or next day. Lifts are scheduled around your building's operating hours — often after-hours — and replacing one unit at a time means the rest of the building keeps running. Rigging and access are planned in the proposal, not on install day.
Does replacing rooftop units help with Local Law 97 compliance?
It depends on what replaces what. Swapping gas/electric packages for heat-pump RTUs eliminates on-site combustion — a direct LL97 emissions reduction. Replacing an old gas unit with a newer gas unit improves efficiency but does not reduce combustion. Buildings with meaningful gas-fired rooftop fleets should factor LL97 timelines into their replacement sequencing — emissions impact is modeled before equipment is specified.
Which RTU brand is best — Carrier, Trane, York, Daikin, or AAON?
All are credible in the right application. Carrier, Trane, and York dominate volume and parts availability; AAON excels in semi-custom and high-performance applications; Daikin Applied is strong where VRF or applied configurations are in play. The right brand depends on capacity match, efficiency tier, controls integration, and local parts and service support. See Com+ Mechanical's commercial RTU brand rankings for the detail.
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Need a Rooftop Unit Assessed, Replaced, or Installed?
Get an on-site rooftop assessment, a load calculation, and a fixed itemized proposal — not a per-ton guess. Com+ Mechanical repairs, replaces, and installs commercial rooftop HVAC units across New York City and Long Island, with rigging and tenant logistics handled end to end.
Request a Rooftop Assessment