Heil model numbers pack the tier, staging, efficiency, capacity and cabinet size of the unit into one string. Once you know where to split it, a Heil model number tells you almost everything except the unit's age. This guide decodes Heil furnace and air-conditioner model numbers position by position, using the key the manufacturer prints on its product data sheets.
Heil is built by ICP (International Comfort Products, a Carrier company). Heil is an ICP brand. Tempstar, Comfortmaker and Day & Night use the same furnace and outdoor chassis with different badges, so an N9MSB-style string decodes the same way on those nameplates.
Position meanings below follow the ICP model-number identification guide printed on N9MSB-class product data (shared across Heil, Tempstar, Comfortmaker and Day & Night). Letter prefixes can vary by badge and generation; treat this as typical decoding guidance.
Where to Find the Heil Model Number
On a furnace, the rating plate is inside the front door or on the side of the cabinet, usually a foil or paper label with the model (M/N) and serial (S/N) side by side. On an outdoor AC or heat pump it is on the side of the condenser near the refrigerant line connections. Copy the model number exactly as printed, including dashes: the position of each character is what carries the meaning.
Heil Furnace Model Number Format
A typical Heil model number in this family looks like: N9MSB0801716A. Use the table to split it up:
| Position | Characters | Meaning | Example |
|---|---|---|---|
| Tier / brand line | N | N = entry / QuietComfort-class; G / F appear on older mainline families | N (entry) |
| AFUE family | 9 | 9 = 90%+ AFUE; 8 = 80% AFUE | 9 (90%+) |
| Position | M | M = multiposition | M |
| Stages / blower | S | S = single-stage; T = two-stage; V = ECM variable-speed; X = ECM; A = modulating ECM | S |
| Feature | B | B = base AFUE; E = extra AFUE; C = communicating | B |
| Heating input | 060 | 040 / 060 / 080 / 100 / 120 = thousands of BTU/h | 60,000 BTU/h |
| Cabinet width | 17 | 14 = 14-3/16 in.; 17 = 17-1/2 in.; 21 = 21 in.; 24 = 24-1/2 in. | 17.5 in. |
| Nominal airflow | 14 | 08–22 = hundreds of CFM cooling airflow at 0.5 in. w.c. | 1,400 CFM |
| Revision | A1 | Sales (major) + engineering (minor) revision digits | A1 |
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Common Heil Families
The first few characters identify the family, and the family tells you the tier, staging and blower (or inverter class) before you read a single digit of capacity.
| Model prefix | Family | Stages | Blower | Efficiency |
|---|---|---|---|---|
| G9MVE / N9MSE | Heil QuietComfort premium | Two-stage / variable | Variable-speed ECM | Up to 96%+ AFUE |
| N9MSB / G9MSB | Heil QuietComfort / entry 90+ | Single-stage | Multi-speed / PSC or ECM | ~92% AFUE |
| N8MSN / G8MSN | Heil 80% multipoise | Single-stage | Multi-speed | 80% AFUE |
| F9MES / older F* | Legacy Heil condensing | Varies | Varies | 90%+ AFUE |
Heil AC and Heat Pump Model Numbers
Outdoor units use a different string. A typical Heil outdoor model number looks like: N4A336GKA.
| Position | Characters | Meaning | Example |
|---|---|---|---|
| Brand / line code | N4 | Brand letter + platform code (N/H/C/T/D vary by ICP badge) | N4 |
| Series / SEER family | A3 | Letter+digit pair for SEER class and staging (A3 ≈ 13–14 SEER single-stage) | A3 |
| Cooling capacity | 36 | 18 / 24 / 30 / 36 / 42 / 48 / 60 = thousands of BTU/h | 36,000 BTU/h = 3 tons |
| Voltage / phase | G | G / K / A codes for 208/230-1-60 and related electrical options | G |
| Major / minor | KA | Sales and engineering revision letters | KA |
Heil Tonnage by Model Number
Every Heil outdoor unit carries its cooling capacity as a two- or three-digit BTU code. Divide by 12 to get tons (1 ton = 12,000 BTU/h). Furnace numbers carry the gas input instead, so a heating "080" means 80,000 BTU/h of heating, not 80,000 BTU/h of cooling.
| Model code | Size | Cooling capacity |
|---|---|---|
| 018 | 1.5 ton | 18,000 BTU/h |
| 024 | 2 ton | 24,000 BTU/h |
| 030 | 2.5 ton | 30,000 BTU/h |
| 036 | 3 ton | 36,000 BTU/h |
| 042 | 3.5 ton | 42,000 BTU/h |
| 048 | 4 ton | 48,000 BTU/h |
| 060 | 5 ton | 60,000 BTU/h |
Common Heil outdoor families and where they sit:
| Model prefix | Family | Efficiency |
|---|---|---|
| *4A3 / *4A4 | Entry 13–14 SEER AC | 13–14 SEER |
| *4A6 / *4A7 | Mid-efficiency single-stage | 15–17 SEER |
| *4H* heat pumps | Heat pump outdoor units | Similar tonnage coding |
| N-series / H-series | Brand-badged ICP outdoor | Shared chassis across ICP brands |
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What the Heil Model Number Does Not Tell You
The model number says nothing about the unit's age. That is in the serial number, and Heil (like most brands) has changed serial date formats over the years. Use the Heil serial number lookup to turn a serial into a manufacture date, or the HVAC serial number decoder hub for any other brand. The model number also does not tell you whether the unit was installed and charged correctly, which matters as much as the SEER digit for what it actually costs to run.
Decoded Your Heil? Here Is What to Do With It
If the unit is under 10 years old and the model number shows a mid- or high-efficiency family, it is usually worth repairing. If the serial dates it past 12 to 15 years for an AC or 15 to 20 years for a furnace, the capacity and cabinet width you just decoded are exactly what you need to size a replacement. A new system at the same tonnage and input will drop straight into the same duct and gas connections.
Related: Tempstar model number guide · Goodman vs Heil furnace comparison · how to read any furnace data label · Goodman model number decoder.
Heil, and related marks, are trademarks of their respective owners. Furnace Direct is not affiliated with or endorsed by Heil's manufacturer. This page is nominative fair-use reference for homeowners decoding a nameplate.
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