There is no question that energy-efficient facilities save building owners money on their bottom line. Yet, out of all the systems that contribute to an energy-efficient building, rooftop units — specifically HVAC systems — oftentimes go ignored after the installation and until there is a catastrophic failure.
Between regular maintenance budgets being slim to non-existent, to a lack of compelling reason to worry about the systems over our heads, there are many reasons routine maintenance goes unperformed. “The air feels fine in here” mentality is an easy answer to potential problems being ignored.
Yet, the following HVAC system failures pictured and detailed below camouflage their failures by the system over-performing, the air quality deteriorating in a way that cannot be detected and systems compromising toward emergency failure.
… effective preventive maintenance can decrease energy bills by 15 to 20 percent.
If nothing more, take a look at these issues and ask yourself: Is a similar HVAC system offender present on my roof?
The Component-Level Issues That Could Be Affecting Your Rooftop HVAC System
Dampers
Your dampers work simply enough: The top damper lets in outside air and the bottom lets in return air. The two are supposed to mix through the filter for an optimally efficient system.
In the images above, these are similar types of systems and both dampers are supposed to be supplying approximately 10 percent outside air to the system during occupied times and closed while unoccupied. Yet, on the left, the damper is letting in outside air (while the space is unoccupied), and the system is doing extra work to cool outside air, which a tenant and building owner won’t feel in the moment but will see in increased utility bills down the line.
On the right, there is no outside air being let into the system (while space is occupied). Likely the tenants feel comfortable with the temperature but there will be increased carbon dioxide in the air which has the potential to make tenants sleepy and less productive, ultimately degrading the quality of air.
For these errors, either the actuator, motor, signal or linkage is broken. But no one would know it without a skilled professional assessing the system on a regular basis.
System Materials
Depending on the materials you initially invested in, your rooftop equipment may or may not be more susceptible to weathering and aging. Pictured are two similar systems. On the left, the system is just a year and a half old, but a cheap material was used in place of a better one. On the right, the system is five years old but is coated with epoxy and is holding up better. Depending on the materials you use, you will need technicians to check and replace parts more often.
Insect Screens
Your insect screens protect the airflow from more than insects: think birds, bats, rodents. This is an incredibly easy fix and an important aspect to maintaining the integrity of your building’s air quality. Yet, it can go unattended to without proper and regular maintenance.
System Linkage
The linkage between the outside air and return air dampers works by closing one and opening the other to ensure the system is operating at optimal efficiency. In this instance, the linkage has broken, and the unit will not function correctly — operating at 100 percent outside air because the return air cannot open. The indoor air may still be comfortable, but your system is working in overdrive to ensure this is so, and your energy bills will reflect this.
Seals
Rooftop equipment like any other piece of machine has parts that wear out over time, including seals. Here, an oil seal has broken on the fan and sprayed all over the motor. This seal is something a preventive maintenance technician would check and address before these issues arise.
Coils and Condensate
Coils can easily become clogged and cause resulting issues. On the left coils are becoming clogged with dirt and possible biological growth greatly reducing the efficiency of the units and possibly spreading contaminants throughout the building. Tenants may not feel the effects of this, until the air stream is severely contaminated or the unit is so inefficient it cannot properly treat the air or properly dehumidify. As coils become completely clogged, debris can build up in the condensate pan, which can overflow and leak into the building.
Invest for Substantially Increased Efficiencies and Decreased Costs
While preventive maintenance plans for rooftop HVAC units oftentimes lose priority to other building needs, this is a major element in the system of a highly efficient building. And, as you saw above, even when a minor part breaks, your unit may be overtaxing itself to keep your building tenants comfortable — ultimately hiking up your operating costs and threatening to require costly emergency repairs.
But you have the power to ensure your system works for your building’s efficiency, not against it.
Commissioning is an important first step. Work with a building commissioning expert to retro-commission or re-commission your building systems to ensure they are operating as they should.
An expert commissioner at the end of their job will provide a clear, actionable report that breaks down your systems and the components that need regular maintenance and at what intervals they need it, including those of your rooftop units.
By following through with this operations and maintenance schedule, not only will you extend the benefits of the commissioning, you will see your energy bills decrease, your sustainability and efficiency increase, and the life of your rooftop systems lengthen.
This is an investment that is sure to pay for itself. In fact, the National Center for Energy Management and Building Technologies has found that effective preventive maintenance can decrease energy bills by 15 to 20 percent.
To have your building systems commissioned by an experienced professional and brought up to optimal performance you can monitor and maintain regularly, contact us for more information.
