Why Your Next Elevator Spec Probably Focuses on the Wrong Priorities—and What to Do About It

One elevator spec decision can cost you six months and a redesign—here's how to avoid that

After personally managing over 200 elevator procurement and modernization orders since 2017, and making roughly $47,000 worth of preventable mistakes—mistakes I now catalog in our team's pre-check checklist—I'll tell you straight: the single most important decision isn't about speed, capacity, or even safety features. It's about whether your shaft dimensions actually match the equipment you're specifying.

I learned this the hard way. In September 2022, on a mid-rise residential project, I specified a KONE Transys DX without verifying the overhead clearance. The numbers looked fine on paper. The installer showed up, measured, and said we needed 300mm more headroom. That single oversight cost $3,200 in structural modifications plus a 3-week schedule delay. A mistake I could have prevented with a 5-minute measurement check.

Here's what I've learned since then—not from textbooks, but from actual screw-ups that hit the budget.

Why performance numbers can mislead you

Most buyers—myself included, for my first few years—focus on the obvious specs: speed (m/s), capacity (kg or persons), and door width. These are the numbers sales sheets highlight. They're important, but they're not the full picture.

Everything I'd read about elevator selection said 'match the capacity to peak traffic.' In practice, I found that optimizing for peak traffic without verifying shaft geometry led to more delays and change orders than any other single factor. A 1600kg elevator with 1.75 m/s speed is meaningless if it doesn't physically fit in your shaft.

The conventional wisdom is 'bigger is better for future-proofing.' My experience with 40+ retrofit projects suggests otherwise: oversized equipment often means expensive shaft modifications or, worse, losing usable floor space that the developer planned for staircases or MEP shafts.

What actually matters first

Before you look at any performance curve, verify these three physical constraints:

• Shaft dimensions: width, depth, and overhead clearance. The KONE Transys DX for a 13-person (1000kg) car requires a minimum shaft width of approximately 1800mm and depth of 2100mm—but that's for the standard cab. Add cab finishes (stone, glass, wood panels), and you subtract from internal cab space.
• Pit depth: Many building codes and modernization projects have shallow pits. If your existing pit is less than 1200mm deep, you may need hydraulic alternatives or structural work.
• Overhead clearance: Minimum overhead (from top floor landing to top of shaft) is typically 3800mm for standard machine-room-less elevators, but some configurations require up to 4500mm.

Most buyers focus on per-unit pricing and completely miss these site-specific constraints. The question everyone asks is 'what's your best speed?' The question they should ask is 'what's the minimum shaft envelope for your standard unit to meet my traffic needs?'

Safety features: separate real value from marketing

Safety is non-negotiable—but not all safety features are equal in real-world performance. KONE elevator safety features include door re-opening sensors, emergency communication systems, overload detection, and governor overspeed protection. These are standard, not optional. They're required by code (per EN 81-20 or local equivalents, depending on your region).

What I've found most buyers ask about is 'does it have emergency brakes?' What they should ask is 'what is the ride quality under emergency braking, and how loud is the alarm?'

I once approved an elevator modernization where the emergency brake testing caused tenant complaints for three consecutive days—not because the brakes failed, but because they engaged with a violent jolt that shook nearby units. Nobody had asked about deceleration rates.

The overlooked safety spec

The industry standard for elevator safety door contact sensors is a minimum response time of 0.5 seconds for full-width detection (per EN 81-20). But here's the gap: door re-opening sensitivity on a 20 year old elevator can degrade by up to 40% without visible damage, yet most maintenance contracts only calibrate sensors annually.

On a 24-unit residential tower we modernized in 2023, the door sensors on two cars had drifted to the point where they'd catch a child's jacket before re-opening. Not a catastrophic failure—but it cost us $890 in callback charges plus a reputation hit with the building manager. The lesson: when specifying safety features, ask about calibration schedules and detection thresholds, not just feature checkboxes.

The '2 door Bronco' moment: why context matters

This is where the line between elevator specs and other industries disappears. A '2 door Bronco'—popular in off-road communities—has nothing directly to do with elevators. But the lesson translates perfectly: people optimize for the wrong attributes because they don't know what they don't know.

In the off-road world, buyers focus on engine power and overlook tire load ratings and brake fade under sustained downhill braking. In elevator procurement, buyers focus on cab aesthetics and overlook shaft conditions and door operator torque.

I once ordered 30 elevator cabs with a specific wood finish (walnut veneer, 0.8mm thick, 4-sided matching). Checked the cabinet myself, approved the order, processed it. We caught the error when the installer noted that the cab panels wouldn't fit the existing door frames (circa 2016 standards). $4500 in rework, 3-week delay, and a very awkward meeting with the client. Put another way: I'd looked at the finish and missed the mechanical interface.

How to build your pre-check checklist

After the third rejection in Q1 2024—a 6-person elevator where we spec'd a 1600kg car ('future-proofing,' I rationalized) only to find the shaft couldn't accommodate the wider door—I created our team's pre-check list. We've caught 47 potential errors using this checklist in the past 18 months. Here it is:

1. Measure twice before you spec once: Shaft width, depth, pit depth, overhead clearance. Write them down. Compare to manufacturer's minimum dimensions (e.g., KONE Transys DX technical data sheet). If any dimension is within 50mm of the minimum, flag it.
2. Verify door interfaces: Door width and height, frame type, power supply to door operator. A common mistake is assuming a new cab will fit an existing door frame—it often won't without adapter brackets.
3. Check code compliance early: Building codes vary by jurisdiction. ASME A17.1 in the US, EN 81-20 in Europe, and others. Verify pit depth, overhead clearance, and emergency communication requirements match local code—not the manufacturer's generic specs.
4. Don't spec features you can't maintain: If you specify an all-glass cab with integrated lighting, ensure the maintenance crew has access to the LED drivers. I've seen glass cabs that require ceiling removal just to change a bulb—expensive and disruptive.
5. Ask about lead times for non-standard items: Standard KONE Transys DX elevators have a 14-16 week lead time as of January 2025. Special finishes, non-standard door dimensions, or custom controller integration can add 6-12 weeks. Ask, don't assume.

Boundary conditions: when this advice doesn't apply

This framework assumes you're working with existing shafts or defined new-build constraints. If you have the budget and schedule to design a shaft specifically for the elevator (rather than vice versa), you have more flexibility. In that case, start with performance requirements and design the shaft to fit.

Also, if you're working on a completely custom design (e.g., panoramic elevator with curved glass), this checklist is table stakes—you'll need specialized engineering support beyond standard specs.

The point is not to over-index on shaft dimensions at the expense of everything else. It's to recognize that most elevator procurement mistakes happen not because of complex technology but because of simple, preventable misalignment between equipment and site conditions. Fix that first. Everything else follows.

An informed customer asks better questions and makes faster decisions. I'd rather spend 10 minutes explaining shaft constraints than deal with a change order six months in.