Older Building-Age Comparison: Office Replacement Work Nearly Doubles, Routine Revenue Stays Flat

The 1.85x office result below comes from an older comparison. We have not confirmed its original data version or which buildings were included. The current published building dataset reports 1.74x for its office replacement-revenue comparison. The Level billing figures below, including healthcare, retail, 3 of 12 segments, 25,912 buildings, the 36% relationship-end comparison and rank correlations, come from that older comparison. Federal PBRB figures, ASHRAE equipment-life figures and illustrative prices use the sources named beside them. The comparisons use different groups and measure revenue, rather than service cost. See the current results and methodology.

The Test That Says Age Does Not Matter

Ask any mechanical contractor whether a 1970s office building costs more to look after than a 2015 one and he will say yes without pausing. It is one of the safest assumptions in the trade.

We went looking for it in real billing data, across 25,912 commercial buildings, and the first pass found nothing. Total annual revenue per building was close to flat across vintages. On the strength of that we nearly wrote age off as a driver entirely.

That would have been wrong, and the reason it would have been wrong is the interesting part.

Split The Revenue And The Effect Appears

A contractor's revenue from a building is not one thing. It is routine service, which is inspections and small repairs, and it is replacement, which is a rooftop unit or a compressor going in. Those two lines show different patterns in the office comparison. A pooled total-revenue test also mixes segments with rising replacement work, segments where it inverts, and jobs in the undisclosed middle band. Those mixtures can mask segment differences. The two office lines shown below add to $15,455 for newer buildings and $21,446 for older buildings, about 39% higher. They do not establish a flat office total, because the $5,000-$15,000 job band is not shown.

The older comparison reports this office split. We have not confirmed its original data version or which buildings were included:

In office buildings, routine service does not move. Not slightly: the figure lands within twenty dollars of itself ($8,353 against $8,336), and across all contractors the within-contractor ratio is 1.01, which means effectively no difference.

Replacement work in office buildings nearly doubles: $13,110 / $7,102 = 1.85.

Healthcare is stronger still, moving from $10,191 to $23,500, a 2.31x step on the replacement line.

Why Routine Service Stays Flat

This is the part that surprised us, and a likely explanation is simple.

Routine service is set by the equipment count and the contract, not by the equipment's age. A building with eight rooftop units gets eight units inspected whether they went in during 1994 or 2019. The visits are scheduled, the scope is fixed, and the invoice looks the same. As an illustrative planning assumption, not a figure measured in this dataset or sourced here, a preventive maintenance visit might be priced around $150 to $600 and a seasonal start-up around $350 to $1,200. Whatever your local prices are, check whether your own price sheet is built on unit count and scope, with no age term in it.

Replacement is the opposite. It is driven by what is due, and what is due is a function of how long things have been running.

One Possible Explanation: Staggered Equipment Renewal

It is tempting to explain this as equipment reaching end of life at some age. Do not say that to a facilities professional: he knows his 1968 building has newer rooftops than your model predicts, because someone replaced them in 2011.

The older ASHRAE service-life figures below need to be checked against the original search and equipment groups, including whether the equipment was still operating or had been replaced. Verify them in the ASHRAE Service Life and Maintenance Cost Database before using them to forecast a replacement date. The older range is 11 to 37 years across eight system families. Rooftop units sit around 16 years, chillers longer, boilers longer again, and controls shorter. Nothing lines up. A hypothesis is that staggered equipment ages help explain why the billed-revenue pattern is higher in the 30+ band; the two published age bands do not establish a plateau. The billing data does not directly estimate annual failure probability or prove that mechanism.

The older chiller comparison showed 18 years for equipment still operating and 25 years for equipment replaced. We have not confirmed which units were included. Equipment still working today may last longer, so its current age is not its full lifespan. These figures cannot set a replacement deadline.

A Separate Federal Comparison Points the Same Direction

The federal portfolio offers a separate contextual comparison. It is not a replication of our billed-revenue result.

The Public Buildings Reform Board's March 2026 report on the federal portfolio covers 1,958 buildings and 280 million gross square feet. It names building age as the single greatest correlation factor with building condition, and its deferred-maintenance liability steps from $55 per gross square foot in buildings 1 to 20 years old to $130 in buildings 31 to 75 years old.

That is a step of about 2.4x ($130 / $55 = 2.36), on a different metric, in a different population, and it flattens in the older age bands. The direction matches our replacement line; the size does not match exactly. Our office step is 1.85x and our healthcare step is 2.31x, and those are billed revenue per building, not deferred liability per square foot. The PBRB March 5, 2026 report, page 6, contains the 1,958-building table; page 22 describes its age-correlation analysis.

Be precise about what that figure is, though. Deferred maintenance is work that has NOT been done on a chronically underfunded portfolio, not revenue that was billed. It points in the same direction on a separate population and measure. It does not corroborate the dollar amount.

For contrast, the industry's familiar "2 to 4% of replacement value" maintenance rule of thumb contains no age term at all. We have not documented its origin here, so we do not cite a date for it.

Retail Runs The Other Way, And We Are Not Papering Over It

In retail the effect inverts. Newer retail bills MORE replacement work than older retail: $5,568 against $3,276, a ratio of 0.59.

Two explanations are plausible and we cannot separate them with this data. New retail fit-outs and tenant turnover drive equipment installs, so a recently repositioned space generates capital work that has nothing to do with age. Meanwhile an older strip center on a thin budget defers.

Because we cannot explain it, retail gets no age adjustment. Neither do the other four segments where the effect reverses, or the four where it looks flat. Only 3 of the 12 segments get an age multiplier: the effect reverses in 5 and looks flat in 4. A driver that works in a quarter of cases is a real finding; a driver applied everywhere because it worked once is a wrong answer waiting to happen.

What A Contractor Should Do With This

Three things follow. The first is a targeting decision you can make from public records. The other two need your own billing and service records.

Building age is a candidate why-now signal, not proof of higher service cost. In the office and healthcare comparisons, older portfolios billed more replacement work. That does not establish a premium for every building type or a routine-cost difference. Replacement-heavy work is a fundamentally different revenue mix: lumpier, higher-ticket, and far more sensitive to whether you can fund the material before the customer pays.

Test pricing against your own costs, not vintage alone. If you have been adding a premium to older buildings on the assumption that routine work costs more there, the office data and the within-contractor ratio of 1.01 identify a nearly flat billed-revenue comparison, not proof that your service-cost difference does not exist. Price service off equipment count and scope. Operator check before you change a price sheet: pull 12 months of your own routine tickets (jobs under $5,000), group buildings into under 30 and 30+ years, and compare routine revenue and consistently allocated labor, parts and access cost per unit under contract separately. If older buildings in your book show a higher routine cost per unit, for example because of access, obsolete parts or refrigerant handling, price that specific scope driver rather than the building's vintage.

Do not read a quiet year as a lost account. Replacement revenue is episodic by nature. A 40-year building that billed you $8,000 last year may not have gone cold; it may have a compressor that has not failed yet. Check before you classify it: is the service agreement still active, are routine visits still scheduled, and are replacement quotes still open? Relationships that did end bill about 36% less in this data, so a quiet year is a reason to look, not proof either way.

How This Was Measured

One mechanical contractor's billed revenue from one building, over a year. A building counts once it shows at least six months between its first and last completed job, annualised on that actual window rather than a calendar year. Each contractor holding five or more buildings of a type contributes one average, then those averages are averaged, so a firm with many buildings counts the same as a firm with five. This limits, but does not remove, any one firm’s influence when few contractors contribute.

Jobs of $15,000 or more count as replacement and jobs under $5,000 as routine service. Work between the two sits in neither bucket on purpose: a low-end changeout and a compressor swap land in that gap, and calling the split exhaustive would be false.

The figure includes relationships that ended, not only the ones that lasted. Buildings whose contractor relationship ended bill about 36% less, so this is what an average account is worth including churn, rather than what a good one is worth.

These coefficients are HVAC and mechanical only. The ordering of building types by value is measurably trade-specific: against this ordering, electrical rank-correlates at rho 0.58 and refrigeration at 0.25, and for roofing, grocery moves from the most valuable type to near the bottom. Carrying these numbers into another trade would be visibly wrong rather than approximately right.

The current per-segment table, size comparisons and held-out validation are in the revenue per building by segment dataset, free to cite under CC BY 4.0. This newer version reports 1.74x for office replacement revenue, so not every figure in the older comparison above will match. It also explains which measured cells were withheld. If you want the number for a specific building, the building revenue calculator will take an address.