Lennox SL22KLV-036-230A**
This outdoor unit is certified at 10 different HSPF2 ratings, from 7.8 to 10.5, across 80 certified pairings with 10 different indoor models. The outdoor unit alone does not have an efficiency. The pairing does.
What that costs. At 17.11¢/kWh, delivering a million BTU of heat costs $16.30 at this unit's best certified rating and $21.94 at its worst — the same outdoor unit, 35% apart, decided by which coil is fitted. Over 40 million BTU of delivered heat that is $652 against $877, a difference of $226 a year.
A reference scenario at a national average rate, not a prediction of your bill. Put your own rate and demand in the calculator.
Open this model in the calculator
What identifies this unit
- Brand on the outdoor unit
- Lennox
- Outdoor model number
- SL22KLV-036-230A**
- ENERGY STAR partner
- Lennox Industries
- Refrigerant
- R-454B (GWP:470 | Lower GWP)
- Cooling capacity across pairings
- 33,000 to 35,600 BTU/h
- SEER2 across pairings
- 16.5 to 20.5
- Cold-climate certified pairings
- 76 of 80
- Certified pairings in the list
- 80
The asterisks in this model number are wildcards used by the manufacturer for variations that do not change the certified performance, such as colour or voltage codes. The number on your unit will have characters where the asterisks are.
Why one outdoor unit has 10 efficiencies
HSPF2 is measured for a system: the outdoor unit together with a specific indoor coil and air handler. Change the coil and the airflow, the refrigerant charge and the heat transfer change with it, so the measured seasonal efficiency changes too. The EPA's list records one entry per certified pairing, which is why this model appears 80 times.
That is also why a quote that names only the outdoor unit has not yet fixed the efficiency. The full explanation, with the mechanism.
How the 80 pairings are distributed
| HSPF2 | Pairings | Share | Per million BTU |
|---|---|---|---|
| 7.8 | 1 | 1.3% | $21.94 |
| 8.0 | 3 | 3.8% | $21.39 |
| 8.1 | 4 | 5.0% | $21.12 |
| 8.2 | 5 | 6.3% | $20.87 |
| 8.5 | 20 | 25.0% | $20.13 |
| 9.0most frequent | 21 | 26.3% | $19.01 |
| 9.4 | 10 | 12.5% | $18.20 |
| 9.8 | 13 | 16.3% | $17.46 |
| 10.0 | 2 | 2.5% | $17.11 |
| 10.5 | 1 | 1.3% | $16.30 |
The most frequent is 9.0, at 21 of 80 pairings (26.2%). That is a count of certificates. It is not evidence that your installer is fitting that combination.
Cold-climate certification is not uniform across this model: 76 of the 80 pairings carry it and the rest do not. If cold-climate performance matters where you live, it has to be checked on the specific pairing, not on the model name.
The pairings at each end
These are the certified pairings with the highest and lowest HSPF2 for this outdoor unit. The indoor model is what separates them.
Highest certified efficiency
| Indoor model | HSPF2 | SEER2 | Cooling BTU/h | AHRI certificate |
|---|---|---|---|---|
| CBK48MVT-060-230-** | 10.5 | 20.0 | 35,200 | 216776011 |
| CK40[C,U]T-60C-**+TDR | 10.0 | 19.0 | 35,000 | 217476507 |
| CK40[C,U]T-60C-**+TDR | 10.0 | 19.0 | 35,000 | 217476508 |
| CK40[C,U]T-60C-**+TDR | 9.8 | 18.5 | 35,000 | 217476506 |
| CK40[C,U]T-60C-**+TDR | 9.8 | 18.5 | 35,000 | 217476509 |
Lowest certified efficiency
| Indoor model | HSPF2 | SEER2 | Cooling BTU/h | AHRI certificate |
|---|---|---|---|---|
| CK40[C,U]T-49C-**+TDR | 8.1 | 17.5 | 34,200 | 217895171 |
| CK40CT-49C-**+DF KIT | 8.0 | 17.5 | 33,000 | 218806003 |
| CK40CT-49C-**+DF KIT | 8.0 | 18.0 | 33,000 | 218806002 |
| CK40[C,U]T-49C-**+TDR | 8.0 | 18.0 | 34,400 | 218045626 |
| CK40[C,U]T-49C-**+TDR | 7.8 | 19.0 | 34,800 | 218695107 |
Those certificate numbers open the calculator with that exact pairing selected. The full list of 80 pairings is searchable there by indoor model or AHRI number.
How to verify this against your own quote
- Check the outdoor model number matches. It is on the data plate of the outdoor unit and should be on the quote. Wildcards aside, it should read SL22KLV-036-230A**.
- Get the indoor coil and air handler model numbers in writing. Without them the efficiency of your system is one of the 10 values above, and nobody can tell you which.
- Ask for the AHRI certificate number for that pairing and look it up in the AHRI directory. That certificate is what carries the HSPF2 and SEER2 the manufacturer stands behind. Step by step.
- Put the numbers in the calculator with your own electricity rate to see what the difference is worth over a heating season.
Related
- All Lennox models in the certified list
- Other Lennox models:ML17XP1-036-230A**, EL17XP1-036-230A**, ML17XP1-030-230A**, ML17XP1-018-230A**, ML17XP1-024-230A**, EL17XP1-018-230A**
- Models with a similar spread:Trane 5TWX7024A1, American Standard 5A6H7024A1, Midea MO1HE-H30B-2A, MDV MOD30-30HFN10-M3X
- Why one outdoor unit has several HSPF2 ratings
- How to work out running cost from HSPF2
- What to check on a heat pump quote
Sources
- Certified pairings, HSPF2, SEER2, capacities and cold-climate status: U.S. EPA, ENERGY STAR Certified Ducted Heat Pumps. Retrieved 2026-09-26; most recent certification date in the file 2026-09-23.
- Reference electricity rate 17.11¢/kWh: U.S. EIA, residential average, 2026-07. Used only to put the efficiency spread in dollars.
- Cost arithmetic and its limits: method.
CertifiedSpecs is independent and is not affiliated with, or endorsed by, Lennox, the EPA or AHRI. Nothing here is a recommendation to buy. Sizing and installation decisions belong to a licensed contractor who has seen your home.