Rooftop HVAC Units

An HVAC unit for a rooftop is a self-sufficient unit that provides heating, ventilation, and air conditioning to a commercial or industrial building and is located on the building's roof. These units are designed to regulate the temperature over large areas such as warehouses, offices, and retail spaces. They are comprised of what would otherwise be separate heating components (compressors, fans, and a series of coils that perform either heating or cooling functions) housed in a single, easy-to-access, weatherproof cabinet. The rooftop location and the self-contained nature of the unit's design allow for a lot of flexibility in arranging the other parts of an HVAC system.

With the right kind of maintenance, a rooftop HVAC unit should last between 15 and 20 years. That means, of course, that some units are not making it to the end of those spans, and some are exceeding them. What might account for such variation? In my mind, and in the mind of the EP, who helped me with research for this piece, several factors are at play. The quality of the installation, the intensity of usage, conference conditions, and the kind of inspections and repairs (if any) that happen while the unit is on the roof all seem to affect how long an HVAC unit might last.

The rooftop HVAC system presents numerous advantages for commercial and industrial buildings. Its singular location outside the building allows for nearly unhindered floor space. Nevertheless, placement is not just about space; it is also about access. Rooftop heat pumps, like rooftop units, allow service personnel to perform the normal maintenance that keeps either type of unit running cleanly and efficiently. The rooftop space is also an ideal location for heat pump/rooftop unit noise dissipation because of the distance from occupied spaces.

At a minimum, rooftop HVAC systems should be maintained twice a year, with service ideally timed for the spring and fall. The kind of detailed examination and care that a rooftop-unit demands and deserves can usually be satisfied by a good care contract with a capable and conscientious service provider. It's definitely not a good idea to think that a rooftop-unit is just like an ordinary furnace or air-conditioning system and can do fine without anything but the most rudimentary maintenance on some sort of fall-spring schedule. It is also definitely not a good idea to think that if you can't hear it or see it that it is okay.

Several important aspects determine the pricing of rooftop HVAC systems. First and foremost is size and capacity. Here, the simple rule that larger means costing more operates across the spectrum of rooftop units. Next up, in terms of pricing, are energy efficiency ratings. Brands with good reputations for durability and performance will usually be more expensive. Finally, things like easy installation, local climatic concerns, and specific building requirements (custom versus standard) can affect both the price of the unit and the total investment in the system.

The myriad ways in which rooftop HVAC systems can be tailored to specific structures allow for a level of customization not seen in other types of HVAC systems. The units can be made to any size and to a variety of specs to fulfill the demands of the spaces above and below. They can be outfitted with modern smart tech to allow for not just remote monitoring but also next-level climate control. If you can dream it, you can likely achieve it with a rooftop unit.

Multiple signs point to a need for replacement of a rooftop HVAC unit. First and foremost, watch for your energy bills to increase; that can be a sign that the unit is working harder than it should. Next, pay attention to how often you’re calling for service. A strongly performing unit should only need to be serviced a couple of times a year, while a flagging unit may need several mid-season checkups. Also, take a listen. If you hear anything that you wouldn’t consider "normal sounds," that could mean your unit is in need of a replacement. And of course, if your unit is more than 15 years old, it’s on borrowed time.

Rooftop units for heating, ventilation, and air conditioning are designed to endure a variety of environmental rigors. They have tough, weatherproof outer shells that protect the internal parts from the kinds of high winds and driving precipitation that would challenge most other types of enclosures. They use ultraviolet-resistant coatings to help the tough outer shells withstand long-term exposure to the sun. They have internal parts that are resistant to corrosion.

Today's rooftop HVAC systems are not just designed for efficiency and effectiveness; they're also created with environmental sustainability in mind. Many contemporary designs feature eco-friendly refrigerants with lower global warming potential. Even the average rooftop HVAC model emits fewer greenhouse gases than in years past, thanks largely to the energy-efficient design standard models now adhere to. And when counting all the net GHG emissions associated with a rooftop model, many come up with less than half of the overall mobilization effect of solar power working in tandem with “everything else” that happens on a rooftop.

There are several main ways that rooftop HVAC units differ from ground-based systems. First, rooftop units are completely self-contained, which means there is no need for separate indoor and outdoor components. Second, rooftop units offer a much more compact and streamlined design, which is extremely valuable in urban settings where ground space can be at a premium. Finally, rooftop units are quieter than ground-based systems.