Our take in 30 seconds
Best for: mixed climates with occasional hard freezesStrengths
- Heating efficiency (HSPF2 10) beats 77% of models
- Cooling efficiency up to SEER2 20, better than 72% of models
- Variable-speed compressor: quieter, steadier temperatures and better humidity control
- Uses newer, lower-impact R-454B refrigerant
Good to know
- Efficiency depends on the indoor unit: SEER2 ranges 15.2–20, so ask which pairing you're quoted
Running-cost calculator
Pre-filled with EIA prices · edit any fieldUses the base certified SEER2 (15.2) and HSPF2 (10). Assumes the unit is correctly sized. How we calculate.
Heating capacity as it gets colder
A heat pump's output falls as outdoor temperature drops. This is the certified heat output of the Lennox EL21KLV-036-230A** at the three ENERGY STAR test temperatures (cooling capacity is 34,800 BTU/h for reference).
Retention at 17°F: 96% · at 5°F: 76%. Learn how to use these numbers in our cold-climate guide.
Estimated running cost in every state
Same unit, very different bills: from about $892 a year in Louisiana to $3,099 in Maine, driven by local electricity prices and how much heating or cooling the climate needs. Click a column to sort.
| State | Price | Heating | Cooling | Total / yr |
|---|---|---|---|---|
| Louisiana | 12.87¢ | $303 | $589 | $892 |
| Washington | 14.63¢ | $836 | $117 | $953 |
| Oregon | 15.92¢ | $856 | $164 | $1,020 |
| Tennessee | 13.42¢ | $631 | $399 | $1,031 |
| Mississippi | 14.43¢ | $436 | $595 | $1,031 |
| Nevada | 12.72¢ | $513 | $524 | $1,037 |
| Florida | 14.99¢ | $227 | $824 | $1,050 |
| Kentucky | 13.80¢ | $742 | $348 | $1,089 |
| North Carolina | 14.95¢ | $653 | $445 | $1,098 |
| Arizona | 15.05¢ | $354 | $758 | $1,112 |
| Arkansas | 14.37¢ | $628 | $493 | $1,121 |
| Utah | 13.31¢ | $850 | $274 | $1,124 |
| Idaho | 13.37¢ | $943 | $214 | $1,158 |
| South Carolina | 15.76¢ | $582 | $577 | $1,160 |
| Georgia | 15.90¢ | $588 | $582 | $1,170 |
| Alabama | 16.33¢ | $604 | $598 | $1,202 |
| Oklahoma | 14.82¢ | $697 | $509 | $1,206 |
| Texas | 15.91¢ | $481 | $729 | $1,210 |
| New Mexico | 16.51¢ | $832 | $378 | $1,210 |
| Nebraska | 13.54¢ | $955 | $279 | $1,234 |
| West Virginia | 16.31¢ | $986 | $299 | $1,285 |
| Missouri | 16.02¢ | $915 | $403 | $1,319 |
| Kansas | 15.47¢ | $936 | $390 | $1,325 |
| Virginia | 17.64¢ | $889 | $444 | $1,333 |
| Wyoming | 14.43¢ | $1,212 | $165 | $1,377 |
| Colorado | 17.17¢ | $1,154 | $275 | $1,429 |
| North Dakota | 13.31¢ | $1,297 | $137 | $1,434 |
| Montana | 15.57¢ | $1,308 | $160 | $1,468 |
| Indiana | 17.02¢ | $1,144 | $331 | $1,475 |
| Delaware | 18.70¢ | $1,068 | $428 | $1,496 |
| South Dakota | 15.15¢ | $1,273 | $225 | $1,498 |
| California | 29.75¢ | $900 | $681 | $1,581 |
| Iowa | 17.06¢ | $1,318 | $293 | $1,611 |
| Ohio | 19.38¢ | $1,302 | $355 | $1,657 |
| Maryland | 21.40¢ | $1,222 | $490 | $1,712 |
| Illinois | 19.32¢ | $1,363 | $354 | $1,717 |
| Minnesota | 17.20¢ | $1,560 | $217 | $1,777 |
| Pennsylvania | 21.77¢ | $1,463 | $399 | $1,862 |
| Wisconsin | 19.41¢ | $1,630 | $267 | $1,897 |
| New Jersey | 24.61¢ | $1,488 | $507 | $1,996 |
| District of Columbia | 25.98¢ | $1,397 | $654 | $2,051 |
| Michigan | 22.99¢ | $1,854 | $316 | $2,170 |
| Connecticut | 24.51¢ | $1,812 | $365 | $2,177 |
| Vermont | 23.84¢ | $2,083 | $246 | $2,328 |
| Rhode Island | 28.18¢ | $2,083 | $387 | $2,470 |
| New York | 28.65¢ | $2,118 | $426 | $2,544 |
| New Hampshire | 27.64¢ | $2,322 | $316 | $2,638 |
| Massachusetts | 30.48¢ | $2,355 | $419 | $2,774 |
| Hawaii | 47.18¢ | $79 | $2,808 | $2,888 |
| Alaska | 29.41¢ | $2,965 | $67 | $3,032 |
| Maine | 32.11¢ | $2,805 | $294 | $3,099 |
Similar-size alternatives
Other ducted split system units within ±15% of this model's cooling capacity, sorted by efficiency. Cost difference is versus the Lennox EL21KLV-036-230A** at U.S.-average rates.
| Model | Cooling BTU/h | SEER2 | HSPF2 | 5°F kept | Est. yearly cost | |
|---|---|---|---|---|---|---|
| Ruud UP19AY36AJVC | 34,200 | 19–21 | 10 | 87% | $1,353 (−$80) | Compare |
| Payne 37MUHAQ30AA3 | 30,000 | 15.3–17.5 | 10.8 | 98% | $1,306 (−$127) | Compare |
| Midea MO1HE-H30B-2A | 30,000 | 15.2–17.5 | 10.8 | 98% | $1,309 (−$125) | Compare |
| Bryant 37MUHAQ36AA3 | 36,000 | 15.8–18 | 10.3 | 103% | $1,527 (+$93) | Compare |
| Daikin DH9VSA361CA* | 34,200 | 16.9–21 | 10 | 100% | $1,398 (−$36) | Compare |
| Panasonic CU-HM36BAHU | 36,000 | 15.6–17.4 | 10.3 | 103% | $1,533 (+$99) | Compare |
Full specifications
| Brand | Lennox |
| Outdoor model | EL21KLV-036-230A** |
| Certified by | Lennox Industries |
| Product type | Ducted split system |
| Compressor | Variable-speed (inverter) |
| Refrigerant | R-454B |
| Cooling capacity | 34,800 BTU/h |
| Nominal size | 3 tons |
| SEER2 (certified range) | 15.2 – 20 |
| EER2 (best) | 12.2 |
| HSPF2 (best) | 10 |
| Heating capacity @ 47°F | 33,600 BTU/h |
| Heating capacity @ 17°F | 32,400 BTU/h |
| Heating capacity @ 5°F | 25,400 BTU/h |
| COP @ 5°F | 2.48 |
| ENERGY STAR cold-climate | Yes |
| Certified indoor pairings | 194 |
| Latest certification | 2026-09 |
Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), retrieved November 7, 2026. Capacities and HSPF2 are the highest values across certified pairings; confirm your exact system's AHRI reference number with your installer.
Frequently asked questions
How much does the Lennox EL21KLV-036-230A** cost to run per year?
At the U.S. average residential electricity price of 18.16¢/kWh and typical national heating and cooling hours, we estimate about $1,434 per year ($976 heating, $457 cooling). It ranges from about $892 in Louisiana to $3,099 in Maine.
Does the Lennox EL21KLV-036-230A** work in cold weather?
Yes. It is ENERGY STAR cold-climate certified and delivers 25,400 BTU/h at 5°F, 76% of its 47°F capacity, with a COP of 2.48 at 5°F.
What size is the Lennox EL21KLV-036-230A**?
It is rated at 34,800 BTU/h of cooling, roughly 3 tons, and 33,600 BTU/h of heating at 47°F. Proper sizing should be confirmed with a Manual J load calculation.