In high-density commercial and residential developments, the rooftop serves as a critical mechanical plinth for Package Rooftop Units (RTUs). Placing an HVAC system on a roof is a strategic engineering choice that utilizes the structural load-bearing capacity of the building’s frame to centralize cooling. This placement offers a thermodynamic advantage: because cold air is naturally denser than warm air, downward distribution requires significantly less static pressure from the blower motor. This guide analyzes the forensic benefits of RTUs, including protection from ‘surface-level debris’ and the mitigation of noise-transient pollution.
Why is some air conditioning on the roof?
People place their air conditioners on the rooftop for various reasons like convenience and protection from thieves and vandals. Some other technical reasons include;
- If the air conditioner is installed in a building after full construction and it was later discovered that the rooftop is the only access point for the attic to work the return air duct, and distribution ducting.
- If there is direct access to the ground space that can be used for distribution ducting and when highly valued rentable areas are not occupied by the air handling unit.
Why is air conditioning on the roof in Arizona?
Air conditioners are placed on the roof in Arizona to ensure optimal circulation or flow of air within indoor spaces. Arizona is known for its all-year-round hot weather, and as a result, air conditioning systems have to be placed in a location where a centralized cooling system can be achieved.
Why are ac units on roofs in California?
California is one of the states that experiences, dust storms in the united states. Storm dust is very dangerous for ground-level ac components because it makes it easier for them to accumulate a lot of dust.
Therefore, it is not uncommon to see air conditioning systems being placed on the roof in this kind of location because that would be the safest way to prevent ac units from collecting dust and debris that can harm their components.
Why is air conditioning on roof in Las Vegas?
Las Vegas is known for its triple-digit temperatures and of course, it would only be clever to have your air conditioning systems placed in a location where the uninterrupted flow of air can be ensured all year round and the best location that would ensure your unit can be properly maintained.
One of the reasons why ground-level AC units consume a lot of energy, especially in commercial buildings is that they are always having to take cold upward. Roof-mounted air conditioners consume lesser energy as cold is usually distributed throughout the building in a downward direction.
Why are air conditioners on the roof in Phoenix?
In Phoenix, air conditioners can be placed either on the ground or the roof without any underlying problems or effects. If you see an air conditioner mounted on the roof or the side of the building in Phoenix, be rest assured that the owners of the buildings take that decision after doing their research and figuring out what’s best for their situation.
Why are air conditioner units on roofs in New Mexico?
All states in the southwestern part of the united states including New Mexico have certain things in common, semi to arid weather, higher elevation, and excess snow. All these situations make it ideal for them to mount their air conditioning systems. For example, they all have higher elevations in common which mean their air conditioners will always have to take cooling upward which is believed to consume more energy.
💡 Engineering Insight: While placement helps, many homeowners believe rooftop units are “invincible” to common mechanical failures. To separate structural advantages from operational reality, check our HVAC Myths vs Facts Audit—especially regarding “Self-Cleaning” units and energy consumption.
Pros of ac on roof
So far, we have learned why ac units are mounted on the roofs in some states in the united states, especially the southwestern region. However, much is not said about the possible consequences or the benefits associated with this less conventional placement. Read this section for the pros and cons
1. Easy access during maintenance
Roof-mounted AC provides technicians with enough open workspace that’s it easier for technicians to access and repair your unit.
2. Prone to fewer disruptions
Air conditioners make a lot of noise that many homeowners could see as disruptions, a roof-mounted air conditioner makes noise, but it is less likely to cause a nuisance.
3. Security
Ground-level air conditioners can be easily vandalized, simply because they can be easily accessed by anybody. On the other hand, roof-mounted air conditioners are accessible only through the interior of the building, which means it would be difficult for thieves to access.
4. Maintenance
All the rooftop of an air conditioner we packed in a single unit meaning it will be much easier to repair and maintain them compared to ground-level air conditioners whose components must be splitter between outdoor and indoor units.
5. Lower cost of energy
In rooftop units, cold air is pushed down naturally with the unit consuming less energy. Ground-level air conditioner consumes more energy because they have to work almost as twice as rooftop-bound air conditioners. After all, most times they will have to push cold air upwards.
Cons of ac on roof
Weights
Since all the components of rooftop-based air conditioners are packed in a single unit, they are heavier than ground-based air conditioners. Rooftop air conditioners are so heavy that not all buildings can withstand their weight.
Regulations
Some homeowners associations don’t allow air conditioners on rooftops therefore, before installing your unit, you must check for rules associated with mounting air conditioners on the rooftop.
Cost
Rooftop mounted air conditioners are usually costly because homeowners will have to pay higher installation prices compared to ground-based air conditioners.
💡 Pro Diagnostic Tip: Rooftop units are directly exposed to the highest solar radiation levels. If your RTU is struggling during the afternoon peak, it may be a “High Pressure” trip due to thermal heat-soak. Use our AC Troubleshooting Protocol to check your head pressure and ensure the condenser fins aren’t flattened by hail or debris.
Do roof-mounted air conditioners have better performance?
Yes, roof-mounted air conditioners have better performance. Since roof air conditioners do not have to work as hard as ground-based units before supplying cold air to the building, whether, upward or downward, they will be more energy-efficient and perform better.
Cost of replacing ac unit on the roof
It will cost you about $5500 or $11000 to install your air conditioners on the rooftop.
How to mount an air conditioner on the roof
To mount your air conditioner on the roof, make use of the roof bracket of the air conditioner. The roof bracket should be attached with cladding screws. The bracket can be easily adjusted and can be easily set up to necessary angles.
However, before mounting your air conditioner, you need to first research the right size system for you. By doing this, you will be able to determine whether your roof can withstand the extra weight of the air conditioner.
How to hide a rooftop air conditioner
Although there are many ways you can conceal a ground-based air conditioner, there are only a few options available to conceal a roof air conditioner. Even if you conceal them, they are still going to stick out.
One of the few available options is painting your unit and roof with the same paint. You can also ask an HVAC technician for possible options.