Know Your Building Series: Edition 1 - HVAC

This article is part of the Know Your Building series - a practical guide to the systems, history, and best practices behind commercial building operations. Written for property managers, chief engineers, and building leaders who want to lead their assets with more confidence and less guesswork.

Mastering the Mechanical Room

The mechanical room is like not the most glamorous rom at a property. It smells like grease. The lighting is bad. And, your chief engineer probably has a mental map of every valve, every belt, every sensor in that space and you're relying on that knowledge more than you realize.

HVAC is the system your tenants notice most when it fails and never think about when it works. That's actually the goal. But hitting that goal consistently requires more than a vendor contract and some luck.

Here's what you need to understand.

A Brief History Worth Knowing

Mechanical ventilation in commercial buildings didn't really exist until the early 20th century. Before that, buildings relied on operable windows, high ceilings, and cross ventilation design features deliberately chosen because there was no alternative.

The first large scale air conditioning installation was Willis Carrier's 1902 system at a printing plant in Brooklyn that was designed not for human comfort, but to control humidity for the paper. Comfort cooling came later, largely driven by movie theaters in the 1920s, which became the first public spaces people sought out specifically because they were air conditioned.

By mid century, central chilled water plants and steam boilers were standard in high rise construction. The buildings you're managing today were largely built in that era. The bones are the same, but the controls have changed dramatically.

The 1970s energy crisis forced a reckoning. Buildings that had been designed to consume freely suddenly faced fuel costs and new efficiency standards. The 1975 introduction of ASHRAE Standard 90 was a turning point - it established that building energy performance was a design responsibility, not an afterthought.

Today, you're operating in a world shaped by ASHRAE 90.1, ASHRAE 62.1 (ventilation and indoor air quality), demand controlled ventilation, VFDs, building automation systems, and local energy benchmarking laws. The equipment has gotten smarter. The regulatory environment has gotten stricter. The tenant expectations have gone up.

The Central Plant: What's Actually Running Your Building

The central plant is where the heavy lifting happens. For most commercial buildings, that means some combination of the following:

Chillers remove heat from the building by circulating chilled water to air handling units throughout the building. They come in several configurations - centrifugal, screw, scroll and their efficiency is measured in kW per ton. A well maintained chiller running at design efficiency is one of the best investments in your building. An aging chiller running at degraded efficiency is one of your highest cost problems.

Boilers generate hot water or steam for heating. Natural gas remains the most common fuel source in commercial buildings, though electrification is growing in certain markets as carbon mandates tighten.

Air Handling Units (AHUs) are where the conditioning meets the occupied space. They pull return air, condition it through cooling or heating coils, filter it, and distribute it through ductwork. AHUs are where most tenant comfort complaints originate.

Cooling Towers reject heat from the condenser water loop. They're also the component with the most significant health compliance obligation in your building. More on that shortly.

Preventive Maintenance: The Seasonal Rhythm That Matters

HVAC problems are rarely surprises. They're deferred maintenance that finally ran out of patience.

The seasonal transition windows of spring and fall are your critical intervention points. Spring is for confirming cooling readiness before peak demand arrives. Fall is for confirming heating reliability before the first cold snap. Both seasons are when problems you can fix cheaply become problems you fix expensively if you miss the window.

Spring priorities: Commission chillers and confirm refrigerant levels. Service cooling towers before startup - scale and biological growth accumulate during winter shutdown. Inspect AHU coils and replace filters. Verify BAS cooling sequences are programmed correctly, not still running the winter schedule. Walk economizer dampers and confirm they're operating as intended.

Fall priorities: Inspect and fire boilers before heating season - don't discover a burner problem the first cold morning. Test heating sequences in the BAS. Check heat exchangers and verify water treatment is current. Confirm duct insulation on exterior runs.

Year round, the unglamorous work is what prevents the early am calls: filter changes on schedule, belt inspections, bearing lubrication, condensate drain checks. A condensate drain pan that doesn't drain freely costs nothing to fix in May. The same problem costs thousands when it overflows into a tenant space in August.

The Code and Compliance Layer You Can't Ignore

ASHRAE 62.1 governs minimum ventilation rates for acceptable indoor air quality. This matters more than it did even five years ago - post pandemic, tenants are paying attention to air quality in ways they weren't before. Demand controlled ventilation (DCV) using CO₂ sensors has become common practice in densely occupied spaces, and it's both an efficiency play and a compliance consideration.

Cooling towers carry a specific regulatory obligation under ASHRAE Standard 188 and in many jurisdictions, local health department regulations as well. Legionella bacteria thrive in warm, stagnant water - exactly the conditions in a cooling tower that hasn't been properly treated and monitored. A Water Management Plan is recommended practice under ASHRAE 188 and is increasingly required by local ordinance. If your building doesn't have one, that's a priority conversation with your engineer and water treatment vendor.

Energy benchmarking laws are expanding. New York's Local Law 97, Chicago's Building Energy Use Benchmarking Ordinance, and similar laws in Washington D.C., Boston, Denver, and other cities are creating real financial consequences for buildings that don't perform to established thresholds. Your HVAC system is typically responsible for a large amount of a commercial building's energy consumption. How you operate it directly affects your benchmarking performance and increasingly, your ownership's exposure to penalties.

Repair vs. Replace: The Conversation You Need to Be Leading

ASHRAE publishes life expectancy guidelines for HVAC equipment. Air cooled chillers average 15 - 20 years. Rooftop units run 15 – 20 years. Air handling units typically last 15 – 25 years. Boilers, maintained well, can run 30+ years.

These are averages. They're starting points, not conclusions.

The real question is total cost of ownership. A chiller that's 18 years old, has required $27,000 in repairs over the past three years, and is running at measurably degraded efficiency is a different situation than an 18 year old chiller that's been well maintained and is performing at spec. Age matters. Condition matters more. Repair history matters most.

The framework worth applying: if a piece of equipment has accumulated repair costs exceeding 60% of its replacement value over two years, the financial case for replacement is usually straightforward. The harder conversation is making that case to ownership before failure forces the issue, because emergency replacement costs significantly more than planned replacement, and it happens on the wrong timeline for everyone.

Three questions to ask your engineer this week:

1. Which piece of HVAC equipment are you most concerned about?

2. What are we doing differently this season based on last season's performance?

3. If we have a major comfort failure at 2pm on a Thursday in July, what's most likely to cause it?

If you found this newsletter interesting, consider checking out these past editions:

• The Building Audit You Never Schedule: You know this building, and that might be the problem.

• What Every Property Manager Should Know About Their Building's Systems

• Tabletop Tuesday: Edition 3 - There's Been a Crash in Your Parking Garage

• Things My Engineer Knows That I Don't

• What Is Property Management? The Career Most People Can't Define and Why That's Their Loss

About the Author

Hi, I’m Matt Faupel - Founder of FaupelX and a passionate advocate for unlocking potential in commercial real estate and beyond. Through this newsletter, I share insights, strategies, and tools to help you lead, grow, and stay ahead in a rapidly evolving industry.

At FaupelX, we’re building the next generation of AI-powered resources for property managers, owners, and industry leaders - because the future belongs to those who prepare for it today.

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