HVAC Decoder
HVAC Tonnage From Model Number
Pick the brand or paste any AC, heat pump, or mini split model number and get the nominal tonnage and BTU/h, plus the SEER class and refrigerant generation when the brand's scheme encodes them. 15 of the 15 brand schemes behind it are backed by a manufacturer document we fetched and quoted, each named with the document it was read from and the date it was fetched.
Starting the decoder. The capacity tables below this box are already loaded, so you can read your code off them now.
Nominal capacity from a model number is a nameplate convention, not a measurement. Actual delivered capacity depends on the matched indoor unit, line set, airflow, and conditions. Always confirm against the data plate's BTU/h rating and the AHRI certificate for the matched system.
Checked against the AHRI Certification Directory before it shipped: 13 of 13 brand families agreed, none disagreed. We did not read these capacity codes off the directory. The engine was built from the manufacturers' own nomenclature, then asked to predict what an independent certification body would say, and checked against it. The 2 families not counted (LG multi-split and Nortek/Nordyne) were searched and carry no certified capacity there, so there was nothing to check.
Capacity Code Reference Table
| Model code | Nominal BTU/h | Tons |
|---|---|---|
| 018 | 18,000 | 1.5 |
| 024 | 24,000 | 2 |
| 030 | 30,000 | 2.5 |
| 036 | 36,000 | 3 |
| 042 | 42,000 | 3.5 |
| 048 | 48,000 | 4 |
| 060 | 60,000 | 5 |
Mini splits use the same BTU/1000 idea but print the class directly, including sizes that are not divisible by 6: 09, 12, 15, 18, 24, 30, 36 (9,000 to 36,000 BTU/h, 0.75 to 3 tons). One ton of cooling = 12,000 BTU/h, so any code on the two tables above divided by12 is the tonnage. That division is not universal: several brands publish capacity codes it gets wrong, and this tool reads those from the manufacturer's own table instead. The brands with a dedicated page below print them as follows. Trane prints 19 = 1.5 tons, 25 = 2 tons, 31 = 2.5 tons, 37 = 3 tons, 43 = 3.5 tons, 49 = 4 tons and 61 = 5 tons; Lennox prints 041 = 3.5 tons, 047 = 4 tons and 059 = 5 tons; Goodman and Amana print 019 = 1.5 tons, 025 = 2 tons, 031 = 2.5 tons, 037 = 3 tons and 043 = 3.5 tons. Payne prints 037 as 3 tons on its 16 SEER sheet. Each of those is a code where dividing by 12 lands between two real sizes, so the manufacturer's printed tonnage is the only correct answer. Read each scheme's own source line below rather than treating this list as complete.
Brand Scheme Reference
15 of these 15 schemes are backed by a manufacturer document we fetched and quoted, named in the sources below. Read each scheme's own source line belowfor which it is: the Confidence column rates the SOURCE the rule rests on. High means a manufacturer nomenclature document establishes the capacity position; Medium means the sourcing is thinner, or the scheme is document-backed without a fixed capacity position and its own source line says so; Convention means no manufacturer decode chart backs the rule at all. Where a source conflict or single-sourced claim exists, this decoder either drops the claim or publishes it at reduced confidence with the gap named, rather than guessing. Allied's older 4AC family is routed to a badge but keeps an estimated capacity, because the Allied legends we hold cover its siblings and not it. The ICP series prefix key was on that list and is now verified against ICP's own model number identification guide, which settled it by showing that ICP gives one digit-1 letter to several of its brands at once, so this decoder publishes the product line and refuses to name a maker from the model number.
| Brands | Where the capacity code sits | Also encoded | Confidence | Source |
|---|---|---|---|---|
| Trane, American Standard | Positions 7-8 are the nominal capacity code (4TTR4036N1000 = 36 = 3 tons). Position 6 is the field-connection digit, not part of the capacity. Trane also ships odd codes that are NOT the code divided by 12: 19 is 1.5 tons, 25 is 2, 31 is 2.5, 37 is 3, 43 is 3.5, 49 is 4 and 61 is 5. | Position 1 = refrigerant (2 = R-22, 4 = R-410A, 5 = R-454B), position 5 = the efficiency digit (0 = 20, 3 = 13, 4 = 14, 5 = 15, 6 = 16, 8 = 18, 9 = 19; the R-454B generation reads it as SEER2 and adds 7 = 17). On R-410A models position 2 is the brand letter and position 3 is AC vs heat pump; on the R-454B generation positions 2-3 are instead a two letter system type (HP = heat pump, HC = cold climate heat pump). | Trane: High · American Standard: Medium | 22-1904-1M-ENDLR-PSD004A-ENODR-PSD038A-EN |
| Carrier | Positions 7-8 are the 2 digit BTU/1000 code in the 24 and 25 families (24ABC636A0030 = 36 = 3 tons). The older 38 family carries a 3 digit code after the series letters (38CKC036 = 036). | Leading digits: 24 = AC condenser, 25 = heat pump, 58/59 = gas furnace, and on the R-454B generation 26 = air conditioner and 27 = heat pump. Position 6, the digit before the capacity code, is the SEER class in lettered series (3 = 13, 6 = 16, 1 = 21 in the 24ACC6 family). Refrigerant is not in a fixed digit. This tool reads a capacity out of the 24, 25 and 38 families only: no nomenclature document we hold covers where the capacity code sits in a 26 or 27 model, so those are identified as Carrier and their tonnage is refused rather than guessed. | High | Catalog No 24ABC6-8PD2016cac_nomen |
| Bryant | Positions 7-9 are the 3 digit capacity code, which Bryant labels 1,000 Btuh nominal (126BNA036000A = 036 = 36,000 BTU/h = 3 tons). Bryant numbers these model positions 1 to 12 and then 14, with no position 13. | Position 1 is the product family (1 = air conditioner), position 2 the tier, position 3 the SEER family digit (3 = 13 SEER on the 113A, 6 = 16 SEER on the 126B), position 4 the major series (B = Puron on the 126B) and position 5 the voltage (N = 208/230-1; the 113A also documents P = 208/230-3 and E = 460/3). The two sheets differ after the capacity: the 126B prints a variation digit at position 6 and leaves 10 to 12 undefined, while the 113A uses 6 for the grille, 10 for a design variation and 11 for the region (N = North). Position 14 is the minor series on both, and neither numbers a position 13. | High | Catalog No. PDS126B-10Catalog No. PDS113A-17 |
| Payne | On the two documented families the Nominal Capacity code sits at positions 7-9 (PA13NA036 = 036 = 3 tons). Both fetched sheets print a code-to-tonnage table, so those values are transcribed rather than calculated, and the two families do not print the same set: PA13 prints 018, 024, 030, 036, 042, 048 and 060, while PA16 omits 018 and adds 037, which its own table reads as 3 tons rather than the 3.08 the code divided by 12 would give. The current PA5SAN5 family is a THIRD documented layout with a different code WIDTH: Catalog No. SSG-PA5SAN5-02 puts a TWO-digit Nominal Capacity at positions 8-9 (PA5SAN53602W = 36 = 3 tons) and prints both the BTU/h and the tons for each of 18, 24, 30, 36, 42, 48 and 60, so those are transcribed too. Two sizes are sold and never rated: PA16 049 and 061 appear as unit sizes in SS-PA16NA-02 and -03 while no revision of that sheet gives either a Nominal Capacity, so this tool refuses them by name rather than reading them on a ladder the manufacturer does not print. Payne's remaining families are read by pattern, at whatever position the code falls, and are reported as estimates. | On PA13 and PA16, positions 3-4 are the SEER family digits (PA13 = 13 SEER, PA16 = 16 SEER). That is the family designation, not the unit's rating: SS-PA16NA-08 rates its own tested AHRI combinations between 14.0 and 15.0. Position 5 is the electrical supply and position 6 is the refrigerant (A = R-410A), so on those two families the refrigerant is in the model number. The electrical legend differs between them: SS-PA13NA-08 prints N (208/230-60-1) and P (208/230-60-3, offered only in sizes 036, 048 and 060), while SS-PA16NA-08 prints N alone. Payne's current air conditioners are the PA4S, PA5S and PA8T families. SSG-PA5SAN5-02 covers PA5SAN5 and is fetched, retained and read, so that family decodes at its own documented positions: position 3 is the SEER2 family digit, position 6 the voltage, position 7 the refrigerant (5 = R-454B), positions 8-9 the Nominal Capacity, position 11 the special feature and position 12 the region. PA4S and PA8T are still covered by no sheet this tool holds and are read by pattern. | High | Catalog No. SS-PA13NA-08Catalog No. SS-PA16NA-08Catalog No. SSG-PA5SAN5-02Catalog No. SSG-PA5SAN5-01Catalog No. SS-PA16NA-03Catalog No. SS-PA13NA-07 |
| Heil, Tempstar, Comfortmaker, Arcoaire, KeepRite, Day & Night, Airquest | Digits 5-6 are the nominal capacity code on the R-410A generations (N4A518GKC100 = 18 = 18,000 BTUH = 1−1/2 tons), which ICP prints as 18, 24, 30, 36, 42, 48 and 60. The current R-454B line inserts an OD Design Type digit at position 5, so its capacity code sits at digits 6-7 instead (N5H5S18AKAAA = 18 = 1-1/2 tons). | Digit 1 is the branding TIER on the R-410A generation, not the brand. That tier key is printed by the R-410A guides only: the current R-454B sheet prints digit 1 as Brand, N =Tempstar, with no tier language at all, so this tool publishes no product line for that generation. On the R-410A layout ICP assigns each letter to SEVERAL brands at once, including the one that looks unique: H to Heil, Arcoaire, Airquest, Kenmore and ICP Commercial; C to Comfortmaker, Day & Night, Keeprite and Kenmore; T to Tempstar AND Kenmore; N to the Entry tier of all of them. So no model number can say which of them built the unit and this tool does not guess. The documents spell it Keeprite, and they also cover Kenmore and ICP Commercial, which this tool does not offer as brands. Digit 3 is the type (A = air conditioner, H = heat pump). Digit 2 is the refrigerant, and each sheet prints exactly one value for it: Form 421 21 6250 01 prints only "4 = R−410A" and Form N5H5S-21-01PD prints only "5 = R-454B". On the two-stage manuals digit 2 is instead the key characteristic (C = Communicating), so no refrigerant is published for that layout. R-22 is NOT decoded here: the only "2 = R−22" in any of these documents sits in the ACCESSORIES part number guide lower on the same page, where it is digit 5 of an accessory number and not an outdoor unit refrigerant. | High | Form 421 21 6250 01Form 421 04 1701 00Form 428 04 1801 00Form N5H5S-21-01PD |
| Goodman, Amana | Goodman GSX/ASX R-410A models put a 3 digit capacity code at positions 6-8, after the SEER digits (GSX140361 = 036 = 3 tons). That line also ships FIVE codes that are NOT the code divided by 12: 019 is 1.5 tons, 025 is 2, 031 is 2.5, 037 is 3 and 043 is 3.5. Goodman's R-32 GLXS/GLZS line uses a 2 digit code at positions 8-9 (GLXS4BA3610 = 36 = 3 tons), and Amana's current ASXS S-series uses a 2 digit code at positions 7-8 (ASXS6S3610A = 36 = 3 tons). | On the GSX/ASX layout position 3 is the unit type (X = R-410A condenser, Z = R-410A heat pump, C = the older R-22 era line) and positions 4-5 are the SEER rating. On the R-32 GLXS/GLZS layout position 2 is L for the R-32 split system line, position 3 is the outdoor type (X = condenser, Z = heat pump) and the tier digit is 4 = 14.3 SEER2, 5 = 15.2 SEER2. Amana's ASXS layout gives position 3 as the unit type and position 4 as the side-discharge cabinet; this tool publishes no refrigerant for that line, because Amana's own spec sheet labels it R-410A while Amana markets it as R-32. | High | SS-GSX14SS-GLXS4B-R32SS-GLZS4B-R32SS-ALZS5B-R32SS-ASX14SS-ASXS6SS-ALXS5B-R32 |
| Daikin | Two layouts, and only the current one has a per-code tonnage table Daikin prints. On the CURRENT twelve-position split-system layout the capacity is TWO digits at positions 7 and 8, between the sales region letter and the electrical digit (DX4SEA3610AA = 3 tons), and Daikin prints seven codes with their tonnage in words. On the OLDER DX16SA-era layout the two digits after DX are the SEER series and the capacity is a three-digit BTU/1000 code at the tail (DX16SA036 = 3 tons); no retained Daikin document prints a legend for that layout, so it is read by the universal convention. Mini splits: BTU/1000 class printed directly (FTX12NMVJU = 12,000 BTU/h, about 1 ton). Daikin's own ductless line is NOT sourced here; the separate mini-split scheme now holds manufacturer sheets for five other brands, and Daikin is not one of them. | The field names on the current layout are Daikin's own, read off its printed Nomenclature: position 1 is the Brand cell (D - Daikin), position 2 the Type (X - AC R-410A, Z - HP R-410A), position 3 an efficiency BAND rather than a rating (SS-DX4SE heads it SEER2 and SS-DZ4SE heads it SEER), position 4 the Compressor (S single stage, T two stage, V variable speed), position 5 the Feature, position 6 the Sales Region, positions 7-8 the Nominal Tonnage, position 9 the Electrical and positions 11-12 the major and minor revisions. The SEER2 digit is deliberately not published as a number because Daikin prints it as a range (13.8 to 14.5 = 4) and the top band is open-ended. On the older DX16SA layout the two digits after DX are the SEER series and the next letter is the stage. | Medium | SS-DX4SESS-DZ4SE |
| Lennox | Capacity is the dash group in BTU/1000 (XC21-036-230 = 3 tons; EL16XC1-048 = 4 tons; SL25KCV-036-230A-1 = 3 tons). The current R-454B line also ships odd codes that are NOT the code divided by 12: 041 is 3.5 tons, 047 is 4 and 059 is 5. The group AFTER the capacity is the voltage (230, 233, 463), not a second capacity. | On the legacy XC/EL/ML models the efficiency lives in the series name, not a dedicated digit (XC21 targets up to 21 SEER, EL16XC1 = Elite 16, ML14XC1 = Merit 14), and the refrigerant is not encoded in a stable position. The current R-454B scheme is different and is documented: SL/EL/ML is the product tier, the next two digits sit in the position Lennox labels Nominal Efficiency, K is the refrigerant (R-454B), then the unit type (C = air conditioner, P = heat pump, L = cold climate heat pump) and the compressor stage (1, 2 or V). | High | Form 210965Model Numbering Systems, section 3.1 |
| Armstrong Air, AirEase, Ducane, Concord | Two generations, and only one of them has a per-code tonnage table. On the CURRENT R-454B line the capacity is the sixth field, between the compressor letter and the voltage letter P (A7AC14F36P = 3 tons; 7AC14F60P = 5 tons), and Allied prints ten codes with their tonnage in words. Three of the ten are NOT the code divided by 12: 41 is 3.5 tons, 47 is 4 and 59 is 5. On the older R-410A 4SCU line the capacity sits in the same relative place, after the region digit and before the voltage letter P (4SCU16LS136P = 3 tons), and Allied's own literature states it as thousands of BTU rather than as tons, over seven codes from 18 to 60. The group AFTER the voltage letter is the major and minor revision code, not a second capacity. | The field names here are Allied's own. The leading digit is the refrigerant (4 = R-410A, 7 = R-454B). On the R-454B line the leading A is the Brand cell and it names a PAIR, AirEase or Armstrong Air, while the Ducane and Concord form carries no brand cell at all; AC is the product type, the two digits after it are the SEER2 class, and the letter after those is the compressor (F = fixed speed, V = variable speed). On the R-410A 4SCU line the digits after SCU are the SEER class and the two letters after them are ONE field Allied calls the TIER (LS = louvered two-stage communicating enabled, LE = louvered enhanced), not a letter pair to be split. The digit before the capacity is the region restriction. | High | Form Number A7AC14F-200Form Number 7AC14F-200 |
| Rheem, Ruud, WeatherKing, Sure Comfort | Two layouts are documented and the capacity sits in a different place in each. The current families run brand, product category, SEER2, region, refrigerant, then the Capacity cell at characters 7-8 (RA14AZ36AJ1NA = 36 = 3 tons; RD18AY60AJVCA = 60 = 5 tons). The older nine-field layout has no region or refrigerant cell, so the same code sits at characters 5-6 instead (RA1636AJ1NA = 36 = 3 tons). The two cannot be confused: the older layout puts a DIGIT where the current one requires the region letter. The two generations document different capacity sets, and this tool does not pool them. Every current-layout legend prints exactly four codes, 24, 36, 48 and 60, and each spec sheet corroborates its own legend on the same printed page with an Available Models list. The nine-field legacy legends print all seven, 18 through 60. So a current-layout model whose size code is 18, 30 or 42 is REFUSED with the reason printed, because reading it off the code = BTU/1000 pattern would be extrapolating from the manufacturer's own list rather than reading it. | Brand cell: R = Rheem / Ruud, U = Ruud Ultra, S = Sure Comfort / Russel By Rheem, W = WeatherKing, ML = Mainline. Only part of that key is printed by the documents registered for this scheme: the Rheem-published sheets print R as Ruud alone, print Sure Comfort and WeatherKing as bare brand names rather than as lettered rows, and print no U, no ML and no Russel By Rheem anywhere. Those halves are carried by forms 92-104921-25-04 and 92-110354-01-01. ML is two characters and is refused rather than decoded, because this tool carries no Mainline badge and would have to print a Rheem or Ruud label over it. Product category: A = air conditioner, P = heat pump, D = side discharge heat pump. Refrigerant: Z = R-410A, Y = R-454B, W = a future refrigerant. Voltage J = 1 phase 208-230 V 60 Hz is the only voltage any current-layout legend prints; the nine-field legacy sheets also print C for three-phase 208-230 V and D for three-phase 460 V. Type 1/2/3/V = single, two, three stage and fully variable. Controls C/N/U = communicating, non-communicating, other communicating. The region cell prints one value, A for All Regions; a model carrying anything else still reports its size, because that cell is one character wide whatever it holds and the refrigerant letter before the size and the voltage, stage and control letters after it all match the printed key, but this tool publishes no meaning for the letter itself and says so on the result. | High | FORM NO. P22-844 REV. 1FORM NO. A22-336 REV. 5Form No. M22-1090FORM NO. ASC-220 REV. 6FORM NO. A66-221 REV. 5 |
| York, Luxaire, Coleman (HVAC), Fraser-Johnston, Guardian | Two layouts are documented, and each prints its own tonnage legend rather than leaving it to arithmetic. On the current R-454B generation the model runs brand, product type, efficiency, then the Nominal unit capacity (MBH) code at characters 4-5 (YC436E2S11 = 3 tons). On the R-410A YC2/YH2 generation the efficiency-and-staging field is two characters wide (2D, 2E, 2F), so the same capacity code sits at characters 5-6 instead (YC2E36SB21S = 3 tons). The two cannot be confused: that field always begins with 2 and the R-454B efficiency character never does. This layout is not the LX Series, and calling it that was wrong on a published surface: the manufacturer brands guides for XC3, YC3 and YC6 as LX Series too, and every one of those carries the R-454B table with the capacity at characters 4-5. Both legends read 18 = 1.5 ton, 24 = 2, 30 = 2.5, 36 = 3, 42 = 3.5, 48 = 4 and 60 = 5, identically, across a refrigerant change. One code sits OFF that legend: the 2 ton class ships as two units, and YC425E2S11 is published as 2 tons by its own guide's performance section even though 25 appears in no nomenclature table. | Digit 1 is the brand and the manufacturer prints only three values for it: Y for YORK, X for a private brand and R for OTC. It never names which private brand, so this tool refuses to read Luxaire, Coleman, Fraser-Johnston or Guardian out of a model number. Digit 2 is the product type (C = AC, H = HP). The refrigerant is published only from the model's own generation: the R-454B table prints E = R-454B, the LX table prints B = R-410A, and neither key is carried across the generation boundary. The modulating YH9 line is documented as DUAL TONNAGE and is reported as an estimate rather than a single confident decode. | High | Form 6788932-YTG-A-0526Form 6788936-UTG-A-0526Form 6552867-YTG-D-0226Form 6644185-UTG-C-0625Form 6260578-YTG-C-0823Form 6552871-UTG-D-0226Form 6601763-YTG-B-0725Form 6515461-YTD-A-1225 |
| Intertherm, Miller, Gibson, Frigidaire, Maytag, Westinghouse, Tappan, Kelvinator | 3 digit BTU/1000 code in the model suffix, 018 to 060 (ET4BE-036K = 3 tons). | Capacity only per our sources. | Medium | 837G-0925840G-0925 |
| Mitsubishi Electric, Fujitsu, Gree, MrCool, Bosch, Samsung, Midea, Senville, Pioneer, Daizuki, Friedrich | The digits in the model are the BTU/h CLASS divided by 1,000: 09, 12, 15, 18, 24, 30, 36 (MSZ-GS12NA-U1 = 12,000 BTU/h = 1 ton; DIY-36-HP = 3 tons). Those are the classes the sheets held here print; this tool also reads the larger classes 42, 48, 60 on the shared ladder, so AOU48RLXFZ returns 4 tons and 3VIR60HP230V1A returns 5 tons. Both come back as estimates, like every mini split read here. Fujitsu prints some sizes with a SINGLE DIGIT and this tool does not read that rendering: its own submittals print AUU7RLF at 7,000 Btu/h nominal cooling and AUU9RLF at 9,000, and both return no match here, because this tool only reads capacity runs of two or three digits. The 9 class itself is read, as 09. Pad the same code to AUU09RLF and it returns a reading at estimate status, which is how that cause was measured rather than assumed. The class is a name, not a rating, and these makers' own specification tables show the difference. Most models read here are rated exactly the class figure. These are not: Gree's 3VIR24HP230V1A is named 24,000 and its own table rates 22,000 Btu/h cooling, Gree's 3VIR09HP230V1A rates 9,100, Mitsubishi's MSZ-GS15NA-U1 rates 14,000, and MrCool's DIY-24-HP rates 23,000. This tool publishes the class, which is what nominal capacity means; size a charge or a load against the rated figure on the unit's own sheet, not against the digits. | Capacity only. The digits are the manufacturer's capacity CLASS; on Gree, Mitsubishi and MrCool sheets read here, the rated cooling capacity can sit either side of the class (24 rating 22,000, 15 rating 14,000, 09 rating 9,100). | Friedrich, Fujitsu, Gree, Mitsubishi Electric, MrCool: Medium · Bosch, Daizuki, Midea, Pioneer, Samsung, Senville: Convention (no maker chart) | AUU7RLFAUU12RLFAUU18RLF3VIR09HP230V1A3VIR18HP230V1A3VIR24HP230V1ASB_MSZ-GS09NA-U1_MUZ-GS09NAH-U1_202405SB_MSZ-GS12NA-U1_MUZ-GS12NAH-U1_202405SB_MSZ-GS15NA-U1_MUZ-GS15NAH-U1_202405mc-diy-4-br-en-01mc-diy-es-4-ss-en-01Floating Air A2L Select and Pro Submittal (06-26-2024) |
| LG | LG heads this field "Capacity (Cooling capacity in Btu/h)" and enumerates it 9 = 9,000, 12 = 12,000, 18 = 18,000, 24 = 24,000, 36 = 36,000, 42 = 42,000 and 48 = 48,000, so the key is thousands of BTU/h and not hundreds. The key sits immediately after the frame-type letter and the optional indoor or outdoor letter (LSN120HSV5 = 12,000 BTU/h = 1 ton; LS181HSV5 = 18,000 = 1.5 tons). The capacity cell in an LG model carries THREE characters while the legend enumerates one or two, and LG documents the third nowhere, so it is read as no part of the capacity and nothing is published for it. | The field names here are LG's own. Position 1 is L for LG, position 2 the Frame Type (A Art Cool, S Standard, C four-way ceiling-cassette, D ceiling-concealed duct low static, H ceiling-concealed duct high static, V vertical-horizontal air handling), then N for an indoor unit, U for an outdoor unit or neither for a matched system, then the capacity, then the System Type (LG prints exactly one value, H for heat pump), then the Style (SV high efficiency inverter, VP Gallery, YV Premier, EV Mega, V standard inverter, T thermostat compatible, LV extended piping) and finally the generation. The generation values are enumerated by only one of the two manuals held and the decode says so. | Medium | EM_SZ_HighEfficiency_WallMounted_11_22EM_SZ_ArtCoolMirror_WallMounted_09_23 |
| Bard | Digits 2-3 are the Nominal Capacity code, and each of the five fetched Bard sheets prints its tonnage in words rather than leaving it to arithmetic: 12 is 1 ton, 18 is 1.5, 24 is 2, 30 is 2.5, 36 is 3, 42 is 3.5, 48 is 4, 60 is 5 and 72 is 6. The ranges differ by product: the ducted wall-mount air conditioners run 18 to 72 with the one-ton W12 on its own sheet, and the heat pump line stops at 60. Bard's MEGA-TEC line instead carries a THREE digit code at digits 2-3-4 (090 to 180, 7.5 to 15 tons); it is light commercial and this tool refuses it rather than reading two of its three digits. | Digit 4 is the unit type and control location: A is an air conditioner with right or centre controls, L is an air conditioner with left side controls (offered on W18 to W36 only) and H is a heat pump (W18 to W60). Digit 5 is the revision, and on the current generation it carries the refrigerant: F is Bard's R-454B revision, printed as such in both current sheets. The R-410A sheets label digit 5 only as a revision level and never tie it to a refrigerant, so this tool publishes a refrigerant for the F models and none for the others rather than inferring one from the document title. | High | Form No. S3678-0626Form No. S3659-0326Form No. S3595-1124Form No. S3586-1123Form No. S3565-0525 |
5 brands have been re-sourced to their own manufacturer nomenclature documents and have a dedicated page naming those documents: Carrier tonnage by model number, Trane tonnage by model number, Lennox tonnage by model number, Goodman tonnage by model number, Amana tonnage by model number. The remaining schemes above are served by this decoder with the confidence label their sources earn.
The manufacturer documents we hold
64 documents behind 15 of the 15 schemes Where a card says nothing about revision currency, we have not checked it. Each is listed with the reference that makes it re-findable, the edition where the document prints one, the manufacturer host it came from and the date we fetched it, so you can look the same document up and check what we read. Every document listed here was reachable without an account on the date we checked it. Manufacturers retire and re-file literature, so an address that worked for us may not work for you.
These documents print the code's unit but no per-code tonnage table, so each tonnage is arithmetic on a manufacturer-stated unit rather than a transcribed value.
These documents print a per-code tonnage table, so each tonnage is transcribed from the manufacturer's own table rather than calculated.
These documents print a per-code tonnage table, so each tonnage is transcribed from the manufacturer's own table rather than calculated.
These documents print a per-code tonnage table, so each tonnage is transcribed from the manufacturer's own table rather than calculated.
These documents print a per-code tonnage table, so each tonnage is transcribed from the manufacturer's own table rather than calculated.
These documents print a per-code tonnage table, so each tonnage is transcribed from the manufacturer's own table rather than calculated.
These documents print a per-code tonnage table, so each tonnage is transcribed from the manufacturer's own table rather than calculated.
These documents print the code's unit but no per-code tonnage table, so each tonnage is arithmetic on a manufacturer-stated unit rather than a transcribed value.
These documents print a per-code tonnage table, so each tonnage is transcribed from the manufacturer's own table rather than calculated.
Worked Examples
Position 1: digit 4 = R-410A (2 = R-22, 5 = R-454B). Position 2: T = Trane. Position 3: T = split AC condenser (W would be a heat pump). Position 5: digit 4 = SEER class 14. Position 6: 0 = brazed field connection, not part of the capacity. Positions 7-8: 36 = 36,000 BTU/h = 3 tons. Per Trane's own Model Nomenclature diagram in Product Data 4TTR4-L (22-1904-1M-EN).
G = Goodman, S = split system, X = R-410A condenser (the older GSC line was R-22). Digits 13 = 13 SEER. Then 036 = 36,000 BTU/h = 3 tons, and the trailing 1 = 208/230V single phase. Per Goodman's model nomenclature and GSX13 spec sheet.
Leading 24 = AC condenser (25 = heat pump, 58/59 = gas furnace). ACC = series letters. The digit 6 before the capacity code = 16 SEER in the 24ACC6 family (3 = 13 SEER, 1 = 21 SEER). Final 36 = 36,000 BTU/h = 3 tons. Carrier does not put refrigerant in a fixed model digit; it follows from series and manufacture year. Per Carrier 24ACC6 product data.
Mini splits skip the divisible-by-6 ladder and print the BTU class directly: 12 = 12,000 BTU/h, which is 1 ton. Fujitsu's own AUU12RLF submittal prints Nominal Cooling 12,000 Btu/h, and MrCool's 4th Generation sheet prints 36,000 for DIY-36. The class is the name on the box, not a measured rating, and these makers' own tables show the difference: Gree names 3VIR24HP230V1A a 24 and rates it 22,000 Btu/h, Mitsubishi names MSZ-GS15NA-U1 a 15 and rates it 14,000, MrCool names DIY-24 a 24 and rates it 23,000. Friedrich rates its A2L line at exactly the class. Fujitsu also sells single-digit classes this tool refuses rather than guesses at, because it only reads capacity runs of two or three digits. Watch LG: it prints thousands of BTU/h like the rest of this list, and its capacity cell carries a third character LG's own legend does not define, which is why LS181HSV5 is 18,000 BTU/h and not 18,100.
Why Furnace Model Numbers Break the Rule
Gas furnace model numbers encode heating input in MBH, thousands of BTU/h of gas input: 070 = 70,000, 090 = 90,000, 110 = 110,000. Many also carry a blower airflow code (16 = 1,600 CFM class) that looks like a capacity code. Neither number is cooling tonnage. Carrier flags its furnaces with the model prefixes 58 and 59, and this decoder reports those as furnaces instead of guessing a tonnage. For system cooling capacity, always decode the outdoor unit's model number. The 060 code is the one collision to watch: on an outdoor unit it means 5 tons of cooling; on a furnace it means 60,000 BTU/h of heating input.
Frequently Asked Questions
How many tons is a 036 model number?
3 tons. The 036 capacity code means 36,000 BTU/h nominal, and one ton of cooling equals 12,000 BTU/h, so 036 divided by 12 is 3 tons. The same math covers the whole residential ladder: 018 = 1.5 tons, 024 = 2, 030 = 2.5, 036 = 3, 042 = 3.5, 048 = 4, and 060 = 5 tons.
Do I use the model number or the serial number to find tonnage?
The model number. It describes what the unit is: capacity, and on many brands the SEER class and refrigerant generation. The serial number describes when the unit was built and carries no capacity information. If you need the unit's age or refrigerant era, decode the serial number instead with our serial number lookup tool.
Where is the model number on the nameplate?
On the data plate (rating plate), a metal or foil sticker on the outdoor unit's side panel near the refrigerant line connections, or inside the front panel on indoor equipment. It is labeled M/N, MODEL, or MODEL NO., usually printed directly above or beside the serial number. Use the outdoor unit's model for system cooling capacity; indoor air handlers and coils carry their own numbers.
Does the model number show the SEER rating?
On many brands, yes, as a rounded class rather than the exact rating. Trane and American Standard carry a SEER digit in position 5 (4TTR4 is a 14 class), Goodman and Amana spell it out (GSX16 = 16 SEER), Rheem and Ruud use positions 3-4 (RA16 = 16 SEER), and Lennox puts it in the series name on the legacy generation (XC21) but gives it a dedicated position on the current R-454B line (the two digits after the SL/EL/ML tier, which Lennox labels Nominal Efficiency rather than SEER or SEER2). Carrier encodes it as a single digit in lettered series (24ACC6 = 16 SEER per Carrier product data). The exact SEER2 rating for a matched system is on the AHRI certificate, not in the model number.
Do the indoor and outdoor model numbers have to match in size?
They should be a rated match, which is not always the same digits. A 036 condenser is often paired with an 037 or 042 coil or air handler, and manufacturers publish approved combinations through AHRI. Mismatched capacity between indoor and outdoor sections costs efficiency and can hurt dehumidification, so verify the pairing in the AHRI directory rather than assuming equal codes.
My furnace model has 070 or 090 in it. Is that tonnage?
No. Furnace model numbers encode heating INPUT in MBH, thousands of BTU/h: 070 = 70,000 BTU/h input, 090 = 90,000. Some furnace models also carry a blower airflow code (16 = 1,600 CFM class) that can be misread as a capacity code. Cooling tonnage for a split system lives in the outdoor unit's model number. Carrier makes this easy to spot: model prefixes 58 and 59 are gas furnaces.
Can I size the replacement system from the old unit's tonnage?
Treat the old tonnage as a starting clue, not an answer. Industry studies have found a large share of residential systems oversized, and an oversized unit short-cycles, dehumidifies poorly, and wears out faster. The original unit may also have been sized before insulation, window, or envelope changes. Run a load calculation first: our BTU calculator estimates the load from climate zone, square footage, insulation, and windows, and a Manual J from your contractor settles it.
What if two digit groups in my model number both look like capacity codes?
It happens, especially with voltage blocks (230, 208) and series numbers next to the real capacity code. This decoder ranks every plausible group and shows its reasoning instead of guessing silently: 3 digit zero-padded groups like 036 outrank bare pairs, and leading digits are usually a product family code, not capacity. When the brand is selected, the brand's documented position wins. If two readings survive, check the nameplate's RLA or BTU/h rating to break the tie.
Related Tools
HVAC Serial Number Lookup
Decode the manufacture date and refrigerant era from the serial number for 40+ brands. Model tells you what it is; serial tells you how old it is.
Gas Pipe Sizing Calculator
Decoded a gas furnace? Its nameplate input is what the gas piping has to carry. Sizes every section of the system rather than one pipe, natural gas or propane.
BTU / HVAC Load Calculator
Size the actual cooling and heating load by climate zone, insulation, windows, and duct location. Check it against the decoded nominal tonnage.
Superheat & Subcooling Calculator
Verify the charge once you know what you are working on. PT interpolation for 11 refrigerants including R-454B and R-32.
MCA / MOCP Breaker & Wire Size Calculator
Got the tonnage? Size the circuit next: enter the nameplate MCA and MOCP and get wire, breaker, ground, and voltage drop per NEC Article 440.
Decoded the tonnage? Check it against the actual load.
The old unit's nominal size is a clue, not a load calculation. Oversized systems short-cycle and dehumidify poorly. Run the load numbers before you match a replacement.