Air-source heat pumps
Lennox SL25XPV Variable-Capacity Heat Pump
Prices are the equipment only — the appliance, before install labour. Where we could only find an installed price, the labour is a national planning estimate backed out to approximate the equipment, so treat those as rough. Get contractor quotes for the install itself.
Lennox's flagship variable-capacity ducted heat pump, among the highest SEER2 in the class, but locked to the iComfort communicating thermostat.
Our take
On paper the efficiency is class-leading. The catch is two-fold: it still runs R-410A, now in phase-down, and it is iComfort-only — you cannot use a third-party thermostat, and when a control board fails years out you are tied to a Lennox dealer to diagnose it. In a mild climate the efficiency is real; in a cold one the -4°F heating lockout is a hard limit.
Best for
Cooling-dominated or mild climates where peak SEER2 matters most.
Watch out for
R-410A refrigerant, a -4°F heating cutout, and total lock-in to the iComfort control.
How it performs by climate zone
Heating capability against each zone's 99% winter design temperature.
| Zone | Design temp | Verdict |
|---|---|---|
| 3C — Warm – Marine | 36°F | Strong fit Rated to -4°F, comfortably below this zone's 36°F design temperature. |
| 4A — Mixed – Humid | 14°F | Strong fit Rated to -4°F, comfortably below this zone's 14°F design temperature. |
| 4B — Mixed – Dry | 18°F | Strong fit Rated to -4°F, comfortably below this zone's 18°F design temperature. |
| 4C — Mixed – Marine | 27°F | Strong fit Rated to -4°F, comfortably below this zone's 27°F design temperature. |
| 5A — Cool – Humid | 2°F | Workable Rated to -4°F against a 2°F design temperature — enough margin, though backup heat will run on the coldest days. |
| 5B — Cool – Dry | 3°F | Workable Rated to -4°F against a 3°F design temperature — enough margin, though backup heat will run on the coldest days. |
| 6A — Cold – Humid | -8°F | Not suitable Rated only to -4°F, but this zone's design temperature is -8°F. |
| 6B — Cold – Dry | -10°F | Not suitable Rated only to -4°F, but this zone's design temperature is -10°F. |
| 7 — Very Cold | -20°F | Not suitable Rated only to -4°F, but this zone's design temperature is -20°F. |
| 8 — Subarctic | -40°F | Not suitable Rated only to -4°F, but this zone's design temperature is -40°F. |
What sellers are actually charging
Real listings, read on the date shown. Prices change — click through to check before you act on any of them.
| Seller | What you get | Price | Seen |
|---|---|---|---|
| Reeis (REEIS)
installer |
Lennox SL25XPV 4-ton variable-capacity heat pump, install package
SL25XPV-048 |
$27,496 | 2026-08-16 |
Equipment price is not installed price. The listings above are what the hardware costs. Installation — labour, electrical, refrigerant lines, permits, removing the old system — is typically a similar amount again, and varies more between contractors than between brands. Where we have an installed figure it is labelled as such and comes from someone who actually installs.
Compare against
Mitsubishi P-series PUZ-AK48NLHZ Hyper-Heat Ducted System
Mitsubishi's 4-ton ducted Hyper-Heat system on R-454B — the best-documented cold-climate performer in this set, NEEP-listed with a full 5°F dataset.
Carrier Infinity 24 Heat Pump with Greenspeed Intelligence (25VNA4)
Carrier's flagship variable-speed ducted heat pump, and one of very few conventional split systems that holds full heating capacity down to 0°F.
Mitsubishi M-Series SUZ-AK36NLHZ Hyper-Heating
Mitsubishi's ducted Hyper-Heating outdoor unit, pairable with a conventional air handler for whole-house ducted retrofit.
Bosch IDS Ultra Inverter Ducted Split
Variable-speed ducted heat pump that undercuts the premium American brands on price while matching most of their cold-weather capability.
Before you buy this
Ask the contractor for the AHRI certificate number for the specific indoor/outdoor combination being installed — ratings apply to matched pairs, not to the outdoor unit alone. Ask whether they will perform a Manual J load calculation rather than sizing off the equipment being replaced. And check your state and utility incentive programmes: there is no federal tax credit for a 2026 installation, so those programmes are now the only incentive money available, and many require approval before installation.