Replacing an AAON Rooftop Unit: Curb Compatibility Guide

By Taylor Metals — SMARTCurb Engineering  ·  Updated August 24, 2026  ·  4 min read

42 verified AAON RTU curb footprints — and an honest look at why over a third of them need a few numbers typed in by hand before SMARTCurb can compile an adapter.

What SMARTCurb has on file for AAON

SMARTCurb has verified curb geometry for 42 AAON rooftop-unit models. AAON's model records happen to be split across two listings in the atlas due to a naming variation in the source data ("AAON" and "Aaon") — between them, browse the larger AAON listing and the second listing for the full set.

AAON's model families

The RN family is the largest in the atlas by far, spanning multiple cabinet sizes from small packaged units up through large-tonnage platforms — RN06/07/08/010, RN009/011/013/015, RN016/018/020/025/030, and RN026/31/40/50/60/70 all appear as distinct size tiers, several of them further split into cabinet-orientation variants (vertical, horizontal/RNA, and lettered configuration suffixes). The RQ family (RQ002-006) covers smaller packaged units. Rounding out the atlas: RH (26-60), RE/RG/RH/RK (16-25, a shared-curb group across those four AAON series letters), and HB (2-5), a smaller packaged line. If your AAON nameplate reads one of these prefixes, it's on file with a verified overall curb footprint.

The honest story: AAON and opening dimensions

This is worth being direct about rather than glossing over. Of the 42 AAON models SMARTCurb has verified, 15 — over a third — have their overall curb footprint confirmed but the supply and return opening positions not resolvable from AAON's available published documentation. The curb size is real and on file; where exactly the ductwork openings sit within that footprint isn't printed clearly enough in AAON's literature to extract with confidence. Compare the AAON RN-014 page (positions not yet resolved) with the AAON RN06/07/08/010(D) page (positions fully verified) — both are real, current AAON families, and both have a confirmed curb footprint; only one has the opening positions pinned down from the source documentation.

SMARTCurb doesn't paper over that gap with a guess. When you pick one of these units in the workspace, it tells you exactly which of the eleven fields are still unknown and lets you enter the real measurements from the field — the same convention covered in how to measure an existing roof curb, outside-corner datum included. Fill in what's missing and the adapter compiles from your real numbers instead of a documentation gap nobody flagged.

Why this happens with AAON specifically

Every manufacturer's published curb literature is a little different in what it dimensions and what it leaves as "field verify." For a meaningful share of AAON's lineup in this atlas, the overall curb size is the number AAON's documentation reliably gives; the internal layout of the supply and return openings is the number that isn't consistently there. That's a documentation-coverage fact about the source material SMARTCurb has been able to verify, not a judgment about AAON's equipment — and it's exactly the kind of gap the manual-entry flow exists to handle honestly instead of silently.

It's also not an all-or-nothing situation within a single AAON family. Several of the RN cabinet-size tiers appear in the atlas with more than one configuration suffix — a (D), a (P), a (W), and so on — and it's common for some suffixes within the same base tier to have fully resolved opening positions while others don't. That's a real reflection of which specific configuration drawings SMARTCurb's sourcing was able to locate and verify, not a pattern you can predict from the base model number alone. The practical takeaway is the same either way: check the specific model page for your exact configuration suffix, not just the base RN or RQ family, before assuming the opening positions are or aren't already on file.

What a curb footprint alone still gets you

Even on the AAON pages where opening positions aren't yet resolved, the verified overall curb footprint is still real, useful information on its own: it tells you the physical envelope the replacement unit needs to sit within, which is often enough to sanity-check whether a swap is even in the right size range before you invest time in a full field measurement. It's the difference between "probably won't fit, don't bother measuring" and "close enough to be worth measuring properly" — a genuinely useful first filter, just not the whole answer on its own.

Every AAON page carries its original pattern drawing

Every AAON model page in the atlas includes the original curb pattern drawing alongside whatever dimensions are verified, viewable directly on the page — useful as a visual cross-check even on the pages where the opening positions still need field measurement.

Before you order

Confirm the exact model designation on the nameplate, then measure the curb in front of you using the outside-corner datum convention regardless of whether the model page already shows full opening positions — for the roughly one-third of AAON models where SMARTCurb hasn't been able to verify those positions from AAON's own documentation, your field measurement is what fills the gap.

When the replacement isn't AAON-to-AAON

The adapter SMARTCurb compiles isn't restricted to same-brand pairings. Each model page lists nearest-footprint compatible pairings across manufacturers as a starting point. Open the SMARTCurb workspace, pick your existing AAON unit and its replacement, and see the real compiled result.