Most business owners looking at a lease deal focus on the number they can see: the advertised rental rate. That number can be misleading. Two properties in the same Denver submarket, same size, similar location, and the one with the lower rent can easily end up costing $10,000 to $15,000 more per year once you understand how the lease is actually structured. That difference comes down to one question most tenants never ask: is this lease NNN or Gross?
At Fountainhead Commercial, we help Denver business owners sort through exactly this kind of comparison every week. Here is what you need to know.
What Is a Triple Net Lease (NNN)?
A Triple Net Lease, commonly called an NNN lease, is a commercial lease structure in which the tenant pays base rent plus its share of three primary property operating expenses: property taxes, building insurance, and common area maintenance (CAM).
These expenses are typically charged separately from base rent and can fluctuate significantly year-over-year. For example, an industrial property in the Denver metro area might advertise a rental rate of $13/SF NNN, which on the face of it seems like a low rental rate.
In reality, that figure represents the base rental rate only. It does not include the additional operating expenses required under the lease, cost of tenant's utilities, janitorial service and other operating expenses. Depending on the property and negotiated terms, tenants may also pay for landscaping, snow removal, parking lot maintenance, common-area utilities, property management expenses, and other allowable operating costs. NNN leases are frequently encountered when evaluating industrial, warehouse, and flex properties. Historically, NNN lease structures are less common in suburban office submarkets. However, the precise allocation of expenses varies by agreement.
For business owners, the important consideration is understanding exactly which expenses are their responsibility and how those expenses may change over time.
What Is a Gross Lease?
A Gross Lease is a commercial lease structure in which the landlord pays all property operating expenses from the rent collected from tenants during the “base year”.
Instead of charging a lower base rent and separately billing all operating expenses, the landlord generally incorporates the operating expense costs into the base rental rate. For example, an office property may advertise a Gross rental rate of $27 per square foot annually. Typically, this rate would include utilities, janitorial, property taxes, building insurance, and common area maintenance expenses. However, not all Gross leases are structured the same way.
A Full-Service Gross Lease generally includes the broadest range of operating expenses, building services, utilities and janitorial within the quoted rental rate. A Modified Gross Lease divides certain expenses (like electricity and/or other utilities and/or janitorial) between the landlord and tenant according to the negotiated agreement. Some Gross leases also contain Base Year provisions or Expense Stops, allowing landlords to recover certain operating expense increases above an established amount. Consequently, signing a Gross lease does not guarantee you will never see additional charges on your monthly statement.
Bottom line: the label on the lease - NNN, Gross, Modified Gross - is a starting point, not a guarantee. What matters is what the executed lease actually says.
Triple Net Lease vs. Gross Lease: Understanding the Financial Difference
The primary difference between these two lease structures is how operating expenses are allocated between the landlord and tenant. Under a typical NNN lease, tenants pay base rent plus separately calculated property operating expenses. These additional expenses may increase or decrease during the lease term. Under a gross lease, certain operating expenses are incorporated into the rental rate, although additional charges may still apply. Neither structure is inherently better.
An NNN lease may advertise a lower base rental rate, while a gross lease may appear more expensive because operating expenses are included. The challenge comes when business owners compare those rates without accounting for the differences.
Consider a hypothetical Denver-area company evaluating two 5,000-square-foot commercial spaces. Property A is offered at $18.00/SF per year, NNN, with estimated operating expenses of $8.00 per square foot. The combined estimated occupancy cost is $26.00/SF, or $130,000 annually. That equals approximately $10,833 per month. Property B is offered at $27.00/SF per year under a gross lease that includes the same categories of operating expenses, without additional pass-throughs. Its annual cost is $135,000, or $11,250 per month. Although Property A's base rental rate is considerably less expensive, the actual difference is only $5,000 annually.
Now assume Property A's operating expenses increase by $2.00/SF per year while base rent remains unchanged. Its annual occupancy cost would rise to $140,000. Property B could become the less expensive option if its gross rental rate and other charges remained unchanged. These are simplified numbers, they exclude utilities, tenant improvements, and other site-specific costs, but they illustrate the point.
Why Operating Expenses Matter More Than Many Tenants Realize
One of the greatest financial considerations in an NNN lease is the possibility of fluctuating operating expenses. Property taxes, insurance premiums, common area maintenance expenses, and other operating costs will change during the lease term. Depending on the lease agreement, some or all of these increases may be 100% passed through to tenants.
Consider a business occupying a warehouse in Arvada, Golden, or Lakewood. The building may require parking lot repairs, HVAC maintenance or replacement, or improvements to shared areas. Whether the tenant must contribute toward those expenses depends on the specific lease provisions. Routine maintenance and major capital improvements are not necessarily treated the same way.
Certain leases permit landlords to recover capital expenditures, major repairs like roof replacement or HVAC systems, from tenants. Others exclude or cap them.
The allocation of responsibility for roofing, structural repairs, HVAC systems, and other major building components deserves particular attention. Business owners should understand these obligations before signing, especially when considering older properties where deferred maintenance may be a concern.
Another important consideration is whether the lease provides limitations on increases in controllable operating expenses (such as janitorial, landscaping, management fees, snow removal, etc.). Such provisions may be negotiable, depending on the property, landlord, and market conditions.
Understanding CAM Charges and Annual Reconciliations
Common Area Maintenance, or CAM, refers to landlord's operating expenses associated with maintaining shared portions of a commercial property. Depending on the building, these expenses may include landscaping, snow removal, parking area maintenance, common-area lighting, and certain property management costs. In many NNN leases, landlords estimate operating expenses at the beginning of an accounting period (January through December) and collect payments throughout the year.
After the period ends, actual recoverable expenses are compared with the estimated amounts actually collected from tenants throughout the year. This process is known as an operating expense reconciliation. If actual expenses exceed the estimates collected by landlord, the tenant may owe an additional payment. If actual expenses are lower than the estimate, the tenant may receive a credit toward rent due or refund according to the lease terms.
For a business managing its cash flow carefully, an unexpected reconciliation payment can create a financial burden. These payments are often due in a lump sum in April or May. Think about what writing an unexpected five-figure check does to your cash flow in Q2.
Before signing a lease, ask for at least two years of historical operating expense statements, the landlord's current budget, and a clear explanation of how expenses are calculated. And make sure audit rights are in your lease - they matter.
How Gross Leases Can Still Include Unexpected Costs
Gross leases feel predictable. But that predictability depends entirely on what the lease actually says. One of the most common surprises comes from a provision called a base year.
Under this arrangement, the landlord covers specified operating expenses up to the amount established for the base year. For example, a new 5,000 SF lease signed in 2026 in a 100,000 SF office building will probably have a 2026 Base Year and 2026 OpEx are estimated to be $10.60/SF. If those expenses increase above $10.60/SF in 2027, the tenant may be required to pay its pro-rata share (5% in this example) of the increase. Assuming a 4% OpEx increase in 2027 to $11.02/SF, it would cost the tenant $2,100 (Math check: In 2027, 100K SF @ $11.02/SF = $1,102,000; 100K SF @ $10.60/SF = $1,060,000 for 2026 OpEx. The increase is $42K; tenant's pro rata share is 5% = $2,100 expense passed-through to tenant).
A business could therefore experience additional operating expense charges even though its lease is described as 'Gross'.
Other expenses, including separately metered electricity, internet services, parking, or interior janitorial services, may also remain the tenant's responsibility. This is why understanding the difference between Full-Service Gross, Modified Gross, NNN and Absolute NNN lease structures is essential. The label is a starting point. The executed lease is the only thing that determines what you actually owe.
Which Lease Structure Works Better for Denver Office and Industrial Tenants?
The appropriate lease structure depends on the property's characteristics, the company's operating requirements, and its financial objectives. For an industrial tenant, the analysis may focus on the combined cost of base rent, NNN expenses, utilities, equipment maintenance (e.g. HVAC maintenance twice per year), and building repair responsibilities (e.g. roof repairs). A manufacturing or distribution company may also need to evaluate loading access, electrical capacity, warehouse clear height, and the cost of modifying the property to accommodate its operations.
For an office tenant, the analysis may place greater emphasis on building services, parking and related fees, operating expense adjustments, and the overall cost of maintaining a productive workplace that helps attract and retain talent. A professional services company considering office space in downtown Denver, the Denver Tech Center, or the West suburbs may encounter different lease structures across competing properties.
Comparing those properties accurately means converting every lease into a single, consistent number, total occupancy cost per square foot, so you are actually comparing apples to apples.
Why the Lowest Rental Rate Is Not Always the Best Deal
Chasing the lowest rent number is a natural instinct. We get it, commercial real estate is a significant expense. But choosing a property solely on the advertised rental rate is a common and costly mistakes.
A lower rental rate may be offset by higher operating expenses, extensive maintenance obligations, or significant upfront improvement costs.
Conversely, a property with a higher rental rate may offer advantages that justify the difference, including more efficient space, better building systems, favorable improvement allowances, or more predictable expenses. The total financial obligation should be evaluated over the full lease term. This includes base rent, estimated operating expenses, annual increases, tenant improvements, concessions, and other contractual obligations.
A full financial comparison often reveals differences that are completely invisible in a property listing. And that information gives you leverage at the negotiating table.
How Fountainhead Commercial Helps Business Owners Navigate Lease Negotiations
At Fountainhead Commercial, we specialize in representing office and industrial tenants throughout the Denver metro area and Colorado. Our objective is to help business owners make informed real estate decisions while minimizing unnecessary occupancy costs and financial exposure.
When evaluating competing properties, we look beyond the quoted rental rate to understand the complete economic structure of each opportunity. That includes reviewing operating expense obligations, evaluating lease escalation provisions, comparing total occupancy costs, and identifying areas where lease terms may be negotiated.
For NNN leases, we help clients understand the operating expenses associated with a property and evaluate the financial implications of maintenance and repair responsibilities. For gross leases, we examine the treatment of operating expenses, base-year provisions, and potential additional charges. We also assist with negotiating tenant improvement allowances, rental concessions, renewal options, and other terms that can influence the long-term value of a lease.
Our approach is centered on understanding the client's operational needs, financial objectives, and future business plans. Whether a company is considering a relocation, expansion, or renewal of an existing lease, the goal is to secure a property and lease structure that supports the business rather than create unnecessary financial complications.
The Bottom Line: Understand Your Total Occupancy Cost Before Signing
The difference between an NNN and a Gross lease is not a technicality. It determines how the real costs of occupying a building are divided, and over a 3- to 7-year lease term, that difference can add up to tens of thousands of dollars.
An NNN lease may offer a lower advertised base rent but expose tenants to additional operating expenses. A gross lease may provide greater initial predictability, although expense adjustments and exclusions can still apply. Neither arrangement guarantees the lowest overall cost. For Denver business owners evaluating office, industrial, warehouse, or flex space, the most important step is understanding the complete financial commitment before signing.
At Fountainhead Commercial, we help business owners evaluate their options, compare total occupancy costs, and negotiate commercial leases that align with their operational and financial goals.
If your company is approaching a lease expiration within the next 6-18 months, considering relocation, or planning an expansion, contact Fountainhead Commercial to discuss your commercial real estate needs.
