MrCool Universal 15 kW Electric Heat Kit with Circuit Breaker, Fits 2-5 Ton Central Ducted Air Handler (UHK15)
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Key features
- 15 kW resistance heat output, approximately 51,000 BTU, fits 2- to 5-ton MrCool central air handlers
- Integrated circuit breaker included, eliminating the need for a separate disconnect in the air handler
- Designed as a drop-in kit for compatible MrCool Universal ducted air handler cabinets
- Compatible with R-454B refrigerant systems in the MrCool Universal lineup
- Single-stage electric resistance operation suitable for supplemental or emergency heat duty
- 240-volt installation required; dedicated breaker at the main panel is necessary
About this system
The MrCool Universal 15 kW Electric Heat Kit (UHK15) is an add-on resistance heat strip designed to work inside compatible MrCool central ducted air handlers sized from 2 to 5 tons. It provides supplemental or emergency electric heat in climates where a heat pump alone may not keep up during cold snaps, or as a primary heat source in all-electric homes where a gas furnace is not an option. The integrated circuit breaker simplifies wiring and adds a measure of overcurrent protection without requiring a separate disconnect in the air handler cabinet.
At 15 kW, this kit delivers roughly 51,000 BTU of electric heat output, which is a reasonable match for a 3- to 4-ton system doing backup duty, though it will be working near its ceiling in a true 5-ton application on the coldest days. Because it is a pure resistance heater, there is no efficiency multiplier the way there is with a heat pump stage, so operating cost per BTU is higher than heat pump heating. This kit suits homeowners who already own a compatible MrCool air handler and need to add heat capability, or who are replacing a failed heat strip in an existing system. It is not a standalone heating solution and must be matched with the correct air handler model before purchasing.
The UHK15 is a straightforward, competitively priced heat strip that does its job when correctly matched to a compatible MrCool air handler. The built-in circuit breaker is a practical convenience, but the real-world risk is MrCool's well-documented warranty and service difficulties, which matter most if the kit or the air handler develops a problem after installation. Buy it if you already own the compatible air handler and understand you are largely on your own for any post-installation support.
Overall score is the average of the five ratings above.
What we like
- Integrated circuit breaker reduces wiring complexity and parts count
- Competitively priced compared to sourcing a heat kit from a traditional HVAC distributor
- Designed specifically for MrCool Universal air handlers, so fit and compatibility are predictable
- 15 kW output covers supplemental heat needs for most residential 3- to 4-ton applications
- DIY-friendly design consistent with the broader MrCool Universal system approach
Trade-offs
- Pure resistance heating carries the highest operating cost per BTU of any electric heat method
- MrCool warranty claims are documentation-heavy and owners report the company looking for reasons to deny coverage
- Local HVAC technicians often decline to service MrCool equipment, leaving troubleshooting to the homeowner
- Customer service has drawn repeated complaints about long hold times and slow email-based resolution
What homeowners and pros say about MRCOOL
Owners of MrCool Universal systems who have added the heat kit generally report that installation is straightforward if you are comfortable with electrical work, consistent with Home Depot owner ratings that average around 4.5 out of 5 stars on popular MrCool DIY products where self-install ease is the most frequently cited strength. For a heat strip specifically, there is not much to go wrong mechanically, and most owners who match it to the correct air handler report that it heats as expected. The concern is not really the strip itself but what happens if something in the broader system goes wrong. MrCool’s 5th-generation platform is meaningfully more reliable than earlier versions, with roughly 85 percent of 5th-gen units running reliably past year one compared to failure rates closer to 25 percent in the 3rd and 4th generations, but that improvement in the core system does not automatically translate to a smoother warranty experience if a component fails.
HVAC professionals are candid that MrCool equipment presents service challenges. The documented failure modes in the broader MrCool line include loose couplings near the air handler, and the company’s warranty process has drawn consistent criticism for being documentation-heavy and for long customer service hold times with troubleshooting handled by email rather than phone or in-person support. Very few local HVAC technicians will work on MrCool equipment, which means that if this heat kit or the air handler it connects to develops a problem, the homeowner often has to diagnose and resolve it independently. For a simple resistance heat strip that is correctly sized and installed, that risk is manageable. For someone who wants a plug-and-forget installation backed by a contractor network, a heat kit purchased through a Carrier, Trane, or Lennox dealer will deliver more reliable post-sale support even at a higher upfront cost.
Sources: Better Business Bureau MRCOOL reviews, PickHVAC MRCOOL review, AHRI Directory of Certified Product Performance, U.S. DOE appliance and equipment efficiency standards.
How it compares
| Brand | Comparable model | SEER2 | Stage | Price position |
|---|---|---|---|---|
| MrCool | Universal Heat Kit UHK15 | N/A | Single-stage resistance | Value pick |
| Carrier | KFCEH3301N15 Electric Heat Kit | N/A | Single-stage resistance | Mid-range, typically higher than MrCool through dealer channels |
| Trane | BAYEVAC15BKA Electric Heat Kit | N/A | Single-stage resistance | Mid-range to premium, dealer-only distribution adds cost |
| Lennox | ECB29-15CB Electric Heat Kit | N/A | Single-stage resistance | Mid-range to premium, sold through Lennox dealer network |
Competitor rows are comparable single-stage units at similar efficiency; price is relative position, not a quote.
Questions about this system
Will this heat kit work with my specific MrCool Universal air handler model?
MrCool publishes a compatibility list for the UHK15 covering Universal series air handlers from 2 to 5 tons. Check your air handler's model number against that list before ordering, because not every MrCool air handler accepts every heat kit, and a mismatched kit will not seat properly in the cabinet.
Do I need a separate circuit breaker at my electrical panel if the kit already has one built in?
Yes. The integrated breaker inside the kit protects the heat strip itself, but you still need a dedicated double-pole breaker at your main electrical panel sized to the kit's amperage draw, typically around 60 to 70 amps at 240 volts for a 15 kW unit. Check the installation manual for the exact breaker and wire gauge requirements before starting work.
How much will the 15 kW heat strip add to my electric bill?
A 15 kW resistance heater draws roughly 62 amps at 240 volts and consumes 15 kilowatt-hours for every hour it runs at full capacity. At a national average electricity rate, that is roughly $1.50 to $2.00 per hour of runtime, which adds up quickly in sustained cold weather. This is significantly more expensive per BTU than heat pump heating, so this kit is best used as a backup rather than a primary heat source.
What happens if the heat kit fails under warranty? How hard is the claims process?
MrCool's warranty process is document-heavy, and owners across multiple forums report that the company scrutinizes claims carefully and has denied coverage in cases where installation records or purchase documentation were incomplete. Because few independent HVAC technicians will service MrCool products, diagnosing a failure and gathering the required documentation often falls on the homeowner, which can be frustrating and slow.
Is a 15 kW heat strip enough for a 5-ton air handler in a cold climate?
A 15 kW strip produces roughly 51,000 BTU, which is at the lower end of what a true 5-ton system might need for primary heat on a cold day. For supplemental or emergency duty alongside a heat pump it is generally adequate, but if you are in a climate with extended periods below 25 degrees Fahrenheit and are relying on the strip as the main heat source, you may find it undersized for the largest homes a 5-ton system serves.
Specifications
| Cooling capacity | 5 Ton |
| Refrigerant | R-454B |