Packaged Rooftop Units

Packaged Rooftop Units

Packaged Rooftop Units (RTU) are HVAC units designed to be placed on rooftops. They are used for residential, commercial, and industrial applications. Lightning mechanical offers installation, service, and maintenance for rooftop units across the New York Tri-State area, including New Jersey, Harrisburg, PA, and Southern Maine.

Packaged Rooftop
Packaged Rooftop Units

What are Packaged Rooftop Units?

Rooftop units are heating and air conditioning solutions whose components all come prepackaged in a single large unit to be installed on rooftops. They are highly cost-effective, easy to install, ready-made solutions for cooling or heating all types of multistory buildings, though they are primarily favored by commercial facilities.

Why Choose Packaged Rooftop Units?

Packaged rooftop units offer many benefits over split systems, including:

  • Lower initial cost
  • Reduced installation time - no ductwork or required
  • Minimal Control Wiring Installation - most of the wiring is already done inside the unit
  • Quiet - no deadening required since they are on the roof
  • High Security - The only security restriction needed is rooftop access
  • Ultra High Efficiency
  • Ease of Maintenance - No technicians wandering around your property; they can change filters and audit system performance all from the roof

However, Packaged Rooftop Units do have some drawbacks

  • High Installation Costs - These units can weigh several tons and require large cranes to be placed on top of buildings.
  • Must be Installed by specialized Rooftop Unit Technicians - The all-in-one nature of these air conditioning systems makes them pretty unique to work with (particularly packaged heat pump models)

A Packaged Rooftop Unit is right for you if:

Packaged Rooftop Units

Packaged rooftop units are a cheap to run and simple solution, but the installation cost might be prohibitive for some. If you have a large indoor space to cover with one air conditioning unit, then a Packaged Rooftop Unit might be what your building needs. Low total cost and high reliability make arranging to finance initial installation a common strategy for commercial buildings.

Packaged heat pump models with constant volume powered exhaust are popular refrigeration and heating options for commercial establishments across America.

The grey metal box of an RTU is a common sight on the rooftops of:

  • Banks
  • Supermarkets
  • Movie theaters
  • Office Buildings
  • Shopping Centers and Malls
  • Restaurants
  • Coffee shops
  • Hospitals
  • Hotels

No matter the industry, what this broad range of commercial buildings has in common is a need for cost-effective, ultra-high efficiency, and performance climate management solutions. Having it all in a convenient package rooftop format just makes sense.

Packaged Rooftop Units

Types of Packaged Rooftop Units

Rooftop units can be manufactured as air conditioners, heat pumps, or electric resistance heater systems. They come in a wide array of sizes and capacities designed to suit any type of building. Some may even have multiple refrigerant circuits for cooling different areas at once.

Packaged rooftop units can be configured to use one or multiple indoor units. They are available in both direct expansion (DX) and inverter compressor designs.

RTU Components

Because they are the HVAC equivalent of plug-and-play devices, RTU's come in many different component configurations. Manufacturers know that energy costs are a huge part of the air conditioning system ownership experience and come up with a range of products to suit every situation. Each company puts its own spin on innovative technology to achieve great energy star ratings and force you to compare products carefully.

That being said, packaged rooftop units all operate on the same basic refrigeration principles. The differences arise in the configuration and choice of the following key components.


Compressors are the most important component in a rooftop unit, and manufacturers put a lot of time and effort into their designs. A compressor is essentially a pump for vaporized refrigerant fluid. It compresses it to raise its temperature and powers it through the rest of the system


Condensers are how the system vents excess heat. Not unlike your car's radiator, condenser coils expose refrigerant to the outside air and turn it back into a cool liquid. This process can be assisted by condenser fans to further reduce refrigerant temperatures. Condensers are also sometimes referred to as heat pumps, although this isn't strictly true as heat pumps don't require mechanical input like that of a compressor.

Constant Volume Powered Exhaust

An important feature to mention for RTU's is constant volume powered exhaust; although not a key component of rooftop units or even essential to the refrigeration cycle, powered exhaust systems are a common rooftop cooling solution for small spaces.

In a Constant Air Volume system (CAV), an exhaust fan runs at a constant rate to cool or heat refrigerant. It's an economical solution but not the most energy-efficient. We recommend going with a more modern Variable Air Volume system where the fans are engineered to run at optimal speeds depending on what the outdoor air is currently like and what indoor temperature end users set.

Metering Equipment

Metering devices control the flow of refrigerant that the compressor pushes through. They are either thermostatic or electronic heating valves and are what give the end-user the ability to set their indoor temperature. Opening and closing the valves can make the system pump out heat or cool air indoors by manipulating the amount of refrigerant that reaches the evaporator.


The evaporator coils are what cools or heats your indoor space. They work a lot like the condensers except for the fact they interact with indoor air. By controlling the temperature of the refrigerant running through the evaporator, you can control the temperature of the room.

Packaged Rooftop Units

Which Packaged Rooftop Unit should I Choose?

Lightning Mechanical Services can help you decide which Packaged Rooftop Unit would best suit your needs.

Packaged rooftop units are very good at what they do, but not every unit is right for every building. Our technicians and engineers are factory trained by all of our supported manufacturers and can provide expert insight into the best RTU for you.

Our product offering includes systems with variable capacity range, return air systems, low leak damper economizers, and refrigerant control systems. You don't strictly need to know what all of those terms mean; that's what we're here for. What you do need to know is that choosing us to find the right system for your workplace or retail establishment involves sitting down to compare products, energy cost, and air quality.

You can start with an evaluation of your needs and our recommendation for which Packaged Rooftop Unit is right for you right now! Connect with us, and Lightning Mechanical Services will analyze your requirements to recommend the best solution available on the current market for energy-efficient operation.

Our Brands:

We offer support on the entire product lines of all major air conditioning manufacturers. Our expertise across such a broad range of products leaves us uniquely positioned to find the most energy-efficient air conditioning options for customers in any industry.

Following is an alphabetized list of all the manufacturers whose outdoor air options we support.

Packaged Rooftop

Have you been considering a rooftop unit from a manufacturer not featured on this list? Don't worry! We have a wealth of experience with all the major manufacturers and brands. It may take a little digging to find an appropriate model, but we will help you through every step of the process.

Contact us via email or call us Mondays through Fridays from 8 am to 6 pm for more information.


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