HVAC Takeoff Software

A STACK Alternative for HVAC Duct Takeoff

STACK is one of the most established cloud takeoff and estimating platforms in construction: browser-based, collaborative, multi-trade, with a deep integration ecosystem and a steady release cadence — April 2026's Snap to Plans, for instance, lets estimators snap measurements directly to the underlying PDF geometry while drawing. On September 1, 2026 it launched STACK IQ, which lets users build takeoffs, audit estimates and generate proposals by describing what they need in plain language, with STACK connected to AI models including Claude and ChatGPT. This page is a fair comparison, not a takedown.

The durable difference is who does the measuring. In STACK, the estimator draws the takeoff — faster and more precisely with every release, but drawn by a person, in trade-agnostic units. DuctIQ reads the mechanical PDF itself and returns the duct takeoff: linear feet by system and size, fittings counted by type, SMACNA-aware gauge and pounds, every quantity a reviewable line item, exported to Excel/CSV in one click. If ductwork is where your takeoff hours go, that inversion is the comparison that matters.

What STACK is genuinely good at

STACK earned its position: a cloud platform your whole team can work in simultaneously, plan management and version handling across large sets, takeoff and estimating in one place across every trade you bid, and integrations into the broader construction stack. Tools like Snap to Plans make the drawing of measurements faster and more precise. For a general contractor or a multi-trade sub coordinating estimates across a team, that breadth and collaboration is a real, defensible strength.

STACK IQ adds a conversational layer on top of all of that. STACK says it can audit an existing estimate for items that may be missing before a bid goes out, turn an estimate into a client-ready proposal with internal markups removed, and set up a project from an email. Those are real time savers for a busy estimating team, and they work across every trade STACK covers. The fair question this page asks is the same one we ask of every platform: which of those capabilities measure ductwork for you?

Drawing measurements faster vs not drawing them at all

Every improvement STACK ships to its measure tools shares one assumption: an estimator is drawing the takeoff. Snapping to plan geometry makes each click land more precisely — but a mid-size mechanical set is still hundreds of clicks, and every one carries the interpretation with it: which system this run belongs to, what size that tag says, whether that junction is a tap or a crossing.

DuctIQ removes the drawing step for the duct scope. The engine reads the sheets at scale, traces the runs, separates supply, return, and exhaust, derives fittings from the geometry, reads equipment and air devices from the schedules, and resolves gauge per run. Your role moves from producing the quantities to auditing them — flagged, low-confidence reads first.

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STACK IQ and the audit trail

Conversational AI changes how you ask for work, so the question for a mechanical estimator is what sits under the answer. When an AI assistant builds a takeoff or flags a missing item, you still sign the bid, so you need to see where each quantity came from before you trust it.

DuctIQ is built around that check. Every duct run, fitting, air device and piece of equipment comes back as its own line with a Review Status, the reads the AI was less sure of are flagged with the reason and grouped first, and each line traces back to the sheet it was measured on. You confirm the lines before anything exports to Excel or CSV.

When you see STACK IQ in a demo, ask the same three things of it on your own mechanical set:

• Does it measure the duct from the PDF, or work from a takeoff someone already drew in STACK?
• Can each quantity it produces be traced to the sheet and the run it came from?
• What does a reviewer see before the numbers reach the estimate: statuses, flags, reasons?

When STACK is the right home base

If your estimating team collaborates across trades in the cloud, manages large plan rooms, and bids scopes far beyond mechanical, STACK as the platform of record makes sense — and nothing duct-specific replaces that. DuctIQ is not a plan room, not a multi-trade estimating suite, and not a collaboration platform; it is the duct takeoff done for you.

Because DuctIQ exports standard Excel/CSV, the practical shape for a STACK shop is the same addition we recommend beside any platform: keep STACK as home base, run the mechanical PDF through DuctIQ, and land the duct quantities into your estimate without re-keying.

When DuctIQ earns the duct scope

Bring DuctIQ in when the ductwork is the work:

• Your estimators still draw and classify every duct run while the platform manages the plans.
• You need duct output in mechanical units — LF by system and size, typed fitting counts — not trade-agnostic lengths, areas, and counts.
• You need SMACNA-aware gauge on every line (spec first, labelled minimum otherwise) and pounds by gauge for sheet metal pricing.
• You want low-confidence reads flagged with reasons and sheet-level traceability before anything exports.
• You want a first reviewable takeoff in minutes from a browser upload, with no platform onboarding.

Side by side on the duct scope

Score both on the duct-specific work. Where STACK's public materials are silent on a row, the honest cell is what to verify in a demo — on your own mechanical set.

Fair under uncertainty: STACK is a capable, well-run platform and its collaboration strengths are credited above. The contrast is automation and duct-specific output units, not quality.

Reviewable lines, because automated still means audited

A takeoff nobody drew still has to survive an estimator's scrutiny before it prices a bid. DuctIQ builds the audit in: every duct run, fitting, air device, and piece of equipment returns as a line with a Review Status, the reads the AI was less sure of are flagged with the reason and grouped first, and each line traces to its source sheet. You confirm before anything exports.

The deliverable: Excel that lands in any estimate

DuctIQ exports the full duct takeoff — runs by system, size, and gauge with linear feet, typed fittings, equipment and air devices, sheet-metal weights — as structured Excel or CSV in one click. It drops into a pricing workbook or a platform import without re-keying, so adding DuctIQ beside STACK costs nothing in lock-in either direction.

The sample below comes from the real export pipeline; open the columns before you create an account:

Download the sample takeoff (Excel)Download the CSV versionHow the export is structured

Settle it on one real bid

Take a mechanical set you have already estimated in STACK. Upload the same PDF to DuctIQ — the first takeoff is free — and compare duct linear feet by system, fitting counts by type, gauge handling, and pounds against your drawn numbers, along with the estimator-minutes each path consumed. Keep whichever process your bids trust.

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