A rooftop unit quits in August. The tenant calls the landlord. The landlord points at the lease. The lease says the tenant is responsible to repair and maintain, so the landlord says it is the tenant's problem. The tenant says a dead unit is not a repair, it is a replacement, and replacement is a capital cost the owner keeps. Both are reading the same document and reaching opposite conclusions. This is the most common building-systems fight in Texas commercial real estate, and it lands almost every time on HVAC.
This article is general education, not legal advice and not property management guidance. It explains how responsibility for building-systems repair and replacement typically gets allocated under a triple-net lease, why the repair-versus-replacement line is where the argument actually happens, and how a documented condition baseline at signing protects both sides. Your specific answer lives in your specific lease. Read it, and where real money is at stake, talk to counsel.
What "triple net" actually shifts
A triple-net (NNN) lease is defined by the three nets the tenant carries on top of base rent: property taxes, building insurance, and maintenance. The structure exists so the landlord receives a rent number that is largely insulated from the cost of operating the building. In a single-tenant NNN arrangement, the tenant often takes on nearly all day-to-day building responsibility. In a multi-tenant setting, the maintenance net usually flows through as common-area maintenance (CAM) charges allocated by square footage.
What this means in practice is that routine HVAC work, filter changes, servicing, minor repairs, and a compressor here and there, generally falls to the tenant. That part is rarely disputed. The dispute is not about who services the unit. It is about who buys a new one when the old one is finished.
The dividing line: repair versus replacement
Repair restores an existing system to working order. A capacitor, a control board, a motor, a refrigerant charge, a compressor swap. Replacement is a capital event: the entire unit comes off the roof because it can no longer be economically or safely repaired. Many well-drafted leases treat these as two separate obligations. The tenant is bound to repair and maintain during the term; the landlord retains responsibility to replace major building systems or capital components when they reach the end of their useful life.
The trouble is that plenty of leases are not that precise. A lease that says the tenant shall keep the HVAC in good repair, and stops there, invites the exact standoff in the opening paragraph. Is a total failure still a repair? Does replacing a $12,000 rooftop unit count as keeping it in good repair, or is that a capital item the landlord owns? The language that matters is whether the lease defines terms like capital, structural, or major system, whether it caps the tenant's obligation, and whether it addresses replacement at all. Where the lease is silent, a dispute is close to inevitable.
Why HVAC is the flashpoint
Building systems all age, but HVAC combines three things that make it the recurring dispute. It is expensive to replace, so both parties have real dollars on the line. It has a finite, roughly predictable service life, so failure is a matter of when. And it tends to fail on the seam between repair and replacement rather than falling cleanly on one side. A slab is structural and clearly the landlord's. A leaking faucet is clearly a repair and clearly the tenant's. A dead HVAC unit sits precisely where the lease language is usually thinnest, which is why it produces the argument more consistently than plumbing or electrical.
The condition baseline both sides should want
Most of these disputes are not really about the lease clause. They are about a missing fact: what condition was the system in when the tenant took it on. Without a record, the argument becomes memory against memory. The tenant believes they inherited a unit near the end of its life. The landlord believes it was serviceable at handover and the tenant ran it into the ground. Neither can prove it.
A documented condition baseline at lease signing closes that gap. A Facility Condition Assessmentrecords the observable condition of the building systems the tenant is accepting, with dated photographs, on a known date. It does not decide who pays; the lease does that. What it does is remove the factual dispute sitting underneath the legal one. The tenant is protected from silently inheriting a worn-out system. The landlord is protected from a later claim that a unit was already failing at turnover. Both parties negotiate and read their obligations against the same starting record instead of against each other's recollection.
This is different from using deferred maintenance as negotiating leverage, which is its own subject. Deferred condition can strengthen a tenant's hand at renewal in an office park, and it shapes tenant retention in a strip center. Those articles are about leverage. This one is about allocation: who owns the cost when a system fails, under the structure you already signed. The baseline is the tool that keeps the allocation question factual instead of adversarial.
The practical takeaway
Before you sign, know how your lease treats replacement, not just repair, and know the condition of the systems you are taking on. If you already hold the lease, read the maintenance and repair clause with the repair-versus-replacement line in mind, and document current condition now rather than after something fails. A baseline established under quiet conditions is worth far more than one attempted during a dispute. Read your lease, and consult counsel before the money is on the line.