Air-source heat pumps
Carrier Infinity 24 Heat Pump with Greenspeed Intelligence (25VNA4)
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.
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.
Our take
This is the ducted system to beat in a cold climate. The reason is not its efficiency rating but its capacity curve: most heat pumps quietly shed a third of their output by the time it's 5°F outside, which is exactly when you need it. The 25VNA4 doesn't, so backup heat stays off and your electric bill stays predictable. You pay for that, and you're locked into Carrier's dealer network for service.
Best for
Cold-climate homes with existing ductwork where the owner wants one system to do the whole job without a fossil-fuel backup.
Watch out for
Requires the matching Infinity control and a competent dealer to commission properly. A badly set up variable-speed system performs worse than a good single-stage one.
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 -23°F, comfortably below this zone's 36°F design temperature, and holds 100% of capacity at 5°F. |
| 4A — Mixed – Humid | 14°F | Strong fit Rated to -23°F, comfortably below this zone's 14°F design temperature, and holds 100% of capacity at 5°F. |
| 4B — Mixed – Dry | 18°F | Strong fit Rated to -23°F, comfortably below this zone's 18°F design temperature, and holds 100% of capacity at 5°F. |
| 4C — Mixed – Marine | 27°F | Strong fit Rated to -23°F, comfortably below this zone's 27°F design temperature, and holds 100% of capacity at 5°F. |
| 5A — Cool – Humid | 2°F | Strong fit Rated to -23°F, comfortably below this zone's 2°F design temperature, and holds 100% of capacity at 5°F. |
| 5B — Cool – Dry | 3°F | Strong fit Rated to -23°F, comfortably below this zone's 3°F design temperature, and holds 100% of capacity at 5°F. |
| 6A — Cold – Humid | -8°F | Strong fit Rated to -23°F, comfortably below this zone's -8°F design temperature, and holds 100% of capacity at 5°F. |
| 6B — Cold – Dry | -10°F | Strong fit Rated to -23°F, comfortably below this zone's -10°F design temperature, and holds 100% of capacity at 5°F. |
| 7 — Very Cold | -20°F | Marginal Rated to -23°F with a -20°F design temperature leaves almost no margin. Expect backup heat to carry a meaningful share of the load. |
| 8 — Subarctic | -40°F | Not suitable Rated only to -23°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 |
|---|---|---|---|
| GSHA Services
installer |
Carrier Infinity 24 heat pump, fully installed — low end
25VNA4 |
$12,900 | 2026-08-16 |
| GSHA Services
installer |
Carrier Infinity 24 heat pump, fully installed — high end
25VNA4 |
$18,100 | 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.
What owners and installers report
Collected from trade forums, owner communities and video reviews. Every report links to the original. We synthesise and quote briefly — we don't republish other people's writing.
Every report below traces back to a single source. The sections are broken out by topic because that's how they read, but treat this as one data point, not independent corroboration across topics — a second source agreeing (or disagreeing) would change that.
Controls and compatibility
Thermostat integration, communicating-system lock-in, firmware, and whether the equipment achieves its rated staging in practice. On tankless water heaters this also covers ignition delay and the 'cold water sandwich' effect.
Carrier's communicating architecture only delivers full staging when paired with matching Carrier equipment. Owners pairing an Infinity unit with a non-communicating furnace report getting two of five available stages — paying for modulation the installation cannot use. This is the practical cost of a communicating system and it is not on any spec sheet.
“only utilize 2 stages of the 5 it's capable of, as a result of non-communicating with the furnace” — forum participant homeowner, 2022-08-05
Carrier Infinity Heat Pumps · GreenBuildingAdvisor Q&A · 2022-08-07 · read it in context
Parts and service availability
Whether a technician can get parts and knows the equipment. Consistently the largest gap between brands, and absent from every spec sheet.
Parts availability is the recurring complaint against Carrier Infinity from the service side. On a communicating variable-speed system this matters more than on simpler equipment, because there is more that only a Carrier dealer can diagnose.
“He hates them. Hard to get parts.” — nynick homeowner, 2022-08-07
Carrier Infinity Heat Pumps · GreenBuildingAdvisor Q&A · 2022-08-07 · read it in context
Installation and commissioning
How much the outcome depends on the installer rather than the equipment, and what specifically goes wrong.
Even well-informed owners report significant friction getting these systems specified and commissioned correctly.
“there's still much friction in this portion of electrification even when the homeowner is heavily involved” — paul_wiedefeld homeowner, 2022-08-05
Carrier Infinity Heat Pumps · GreenBuildingAdvisor Q&A · 2022-08-07 · read it in context
Sources are linked so you can verify any of this yourself. We don't mirror content — Amazon in particular permits no republication of review text, so where we use retailer data we show the aggregate rating and link out. How we collect and weight this →
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.
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.
Daikin Fit Aurora DH9VS
Side-discharge variable-speed heat pump with a small footprint, rated for cold-climate operation to -13°F.
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.