Our take in 30 seconds
Best for: mild climates or homes with backup heatStrengths
- Uses newer, lower-impact R-454B refrigerant
Good to know
- Only 48% of its heat output remains at 5°F; plan on backup heat in hard freezes
- Heating efficiency (HSPF2 8.1) is in the lower third of models
Running-cost calculator
Pre-filled with EIA prices · edit any fieldUses the base certified SEER2 (15.2) and HSPF2 (8.1). 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 Fujitsu WP15AY42AJ2N at the three ENERGY STAR test temperatures (cooling capacity is 40,000 BTU/h for reference).
Retention at 17°F: 100% · at 5°F: 48%. Learn how to use these numbers in our cold-climate guide.
Estimated running cost in every state
Same unit, very different bills: from about $1,122 a year in Louisiana to $4,461 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¢ | $445 | $677 | $1,122 |
| Florida | 14.99¢ | $333 | $947 | $1,280 |
| Mississippi | 14.43¢ | $641 | $684 | $1,325 |
| Nevada | 12.72¢ | $754 | $603 | $1,356 |
| Washington | 14.63¢ | $1,228 | $135 | $1,363 |
| Tennessee | 13.42¢ | $928 | $459 | $1,387 |
| Arizona | 15.05¢ | $520 | $871 | $1,392 |
| Oregon | 15.92¢ | $1,258 | $189 | $1,446 |
| North Carolina | 14.95¢ | $960 | $511 | $1,471 |
| Arkansas | 14.37¢ | $923 | $567 | $1,490 |
| Kentucky | 13.80¢ | $1,090 | $399 | $1,490 |
| South Carolina | 15.76¢ | $856 | $664 | $1,520 |
| Georgia | 15.90¢ | $864 | $669 | $1,533 |
| Texas | 15.91¢ | $707 | $837 | $1,544 |
| Utah | 13.31¢ | $1,249 | $315 | $1,564 |
| Alabama | 16.33¢ | $887 | $688 | $1,575 |
| Oklahoma | 14.82¢ | $1,025 | $585 | $1,610 |
| Idaho | 13.37¢ | $1,387 | $246 | $1,633 |
| New Mexico | 16.51¢ | $1,223 | $434 | $1,657 |
| Nebraska | 13.54¢ | $1,404 | $321 | $1,725 |
| West Virginia | 16.31¢ | $1,450 | $343 | $1,793 |
| Missouri | 16.02¢ | $1,345 | $464 | $1,809 |
| Virginia | 17.64¢ | $1,307 | $511 | $1,817 |
| Kansas | 15.47¢ | $1,375 | $448 | $1,823 |
| Wyoming | 14.43¢ | $1,781 | $190 | $1,971 |
| Colorado | 17.17¢ | $1,696 | $316 | $2,012 |
| Indiana | 17.02¢ | $1,681 | $381 | $2,062 |
| Delaware | 18.70¢ | $1,570 | $492 | $2,062 |
| North Dakota | 13.31¢ | $1,906 | $158 | $2,064 |
| California | 29.75¢ | $1,322 | $783 | $2,105 |
| Montana | 15.57¢ | $1,922 | $184 | $2,107 |
| South Dakota | 15.15¢ | $1,870 | $259 | $2,130 |
| Iowa | 17.06¢ | $1,938 | $337 | $2,274 |
| Ohio | 19.38¢ | $1,914 | $408 | $2,322 |
| Maryland | 21.40¢ | $1,797 | $563 | $2,360 |
| Illinois | 19.32¢ | $2,004 | $407 | $2,410 |
| Minnesota | 17.20¢ | $2,293 | $249 | $2,542 |
| Pennsylvania | 21.77¢ | $2,150 | $458 | $2,608 |
| Wisconsin | 19.41¢ | $2,396 | $306 | $2,703 |
| New Jersey | 24.61¢ | $2,188 | $583 | $2,770 |
| District of Columbia | 25.98¢ | $2,053 | $752 | $2,805 |
| Connecticut | 24.51¢ | $2,663 | $419 | $3,082 |
| Michigan | 22.99¢ | $2,725 | $363 | $3,088 |
| Vermont | 23.84¢ | $3,061 | $282 | $3,343 |
| Hawaii | 47.18¢ | $116 | $3,228 | $3,345 |
| Rhode Island | 28.18¢ | $3,062 | $445 | $3,506 |
| New York | 28.65¢ | $3,113 | $490 | $3,603 |
| New Hampshire | 27.64¢ | $3,412 | $364 | $3,776 |
| Massachusetts | 30.48¢ | $3,462 | $481 | $3,943 |
| Alaska | 29.41¢ | $4,357 | $77 | $4,434 |
| Maine | 32.11¢ | $4,123 | $338 | $4,461 |
Similar-size alternatives
Other ducted split system units within ±15% of this model's cooling capacity, sorted by efficiency. Cost difference is versus the Fujitsu WP15AY42AJ2N 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 (−$607) | Compare |
| Ruud UP19AY48AJVC | 45,500 | 18–19 | 10 | 92% | $1,827 (−$134) | Compare |
| Bryant 37MUHAQ36AA3 | 36,000 | 15.8–18 | 10.3 | 103% | $1,527 (−$433) | Compare |
| Daikin DH9VSA361CA* | 34,200 | 16.9–21 | 10 | 100% | $1,398 (−$563) | Compare |
| Panasonic CU-HM36BAHU | 36,000 | 15.6–17.4 | 10.3 | 103% | $1,533 (−$428) | Compare |
| MrCool CENTRAL-36-HP-C-230B00-O | 36,000 | 15.2–17.4 | 10.3 | 103% | $1,545 (−$415) | Compare |
Full specifications
| Brand | Fujitsu |
| Outdoor model | WP15AY42AJ2N |
| Certified by | Fujitsu General America, Inc. |
| Product type | Ducted split system |
| Compressor | Two-stage |
| Refrigerant | R-454B |
| Cooling capacity | 40,000 BTU/h |
| Nominal size | 3.5 tons |
| SEER2 (certified range) | 15.2 – 16 |
| EER2 (best) | 11.7 |
| HSPF2 (best) | 8.1 |
| Heating capacity @ 47°F | 40,000 BTU/h |
| Heating capacity @ 17°F | 40,000 BTU/h |
| Heating capacity @ 5°F | 19,300 BTU/h |
| COP @ 5°F | 2 |
| ENERGY STAR cold-climate | Yes |
| Certified indoor pairings | 56 |
| Latest certification | 2025-04 |
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 Fujitsu WP15AY42AJ2N 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 $1,961 per year ($1,435 heating, $526 cooling). It ranges from about $1,122 in Louisiana to $4,461 in Maine.
Does the Fujitsu WP15AY42AJ2N work in cold weather?
Yes. It is ENERGY STAR cold-climate certified and delivers 19,300 BTU/h at 5°F, 48% of its 47°F capacity, with a COP of 2 at 5°F.
What size is the Fujitsu WP15AY42AJ2N?
It is rated at 40,000 BTU/h of cooling, roughly 3.5 tons, and 40,000 BTU/h of heating at 47°F. Proper sizing should be confirmed with a Manual J load calculation.