Three Heat Pumps, Three Use Cases
All three work in Colorado winters. The right choice depends on your home - we've installed over 4,600 of these three systems combined.
Fully electric, under 2,500 sq ft
→Mitsubishi H2i
Best cold-weather performance, lowest callback rate. Works with or without ductwork.
Ducted home, flexible configuration
→Bosch IDS Ultra
Best all-arounder for ducted retrofits. Pairs with air handler, furnace, or coil-only.
Ducted, watching the budget
→Carrier 37MUH
Solid mid-range ducted option. Operates to -22 degrees F at a lower price point.
Quick Comparison
- Specification
- Min operating temp
- Mitsubishi H2i
- -24 degrees F
- Bosch IDS Ultra
- -13 degrees F
- Carrier 37MUH
- -22 degrees F
- Specification
- 100% capacity down to
- Mitsubishi H2i
- 5 degrees F
- Bosch IDS Ultra
- 5 degrees F
- Carrier 37MUH
- 15 degrees F
- Specification
- Efficiency (cooling)
- Mitsubishi H2i
- Up to 30.5 SEER
- Bosch IDS Ultra
- Up to 20 SEER2
- Carrier 37MUH
- Up to 22 SEER
- Specification
- Configuration
- Mitsubishi H2i
- Ductless + Ducted
- Bosch IDS Ultra
- Ducted only
- Carrier 37MUH
- Ducted (crossover)
- Specification
- Capacity range
- Mitsubishi H2i
- 6K-96K BTU
- Bosch IDS Ultra
- 48K-60K BTU
- Carrier 37MUH
- 9K-36K BTU
- Specification
- Refrigerant
- Mitsubishi H2i
- R-410A
- Bosch IDS Ultra
- R-454B (future-proof)
- Carrier 37MUH
- R-454B
- Specification
- UniColorado installs
- Mitsubishi H2i
- 4,000+
- Bosch IDS Ultra
- 600+
- Carrier 37MUH
- 80+
Mitsubishi HyperHeat
Bosch IDS Ultra
Carrier 37MUH
Mitsubishi H2i (Hyper-Heating): Best for Fully Electric Up to 2,500 Sq Ft
The Mitsubishi H2i is what put cold-climate heat pumps on the map. We've installed over 4,000 of these systems in Colorado, and they have our lowest callback rate of any equipment we carry.
Why It Works
Mitsubishi pioneered flash injection compressor technology with the H2i line. This isn't marketing spin - it's a fundamentally different compressor design that maintains heating capacity when temperatures drop.
H2i Cold-Weather Specs
- 100% heating capacity down to 5 degrees F - most cold-climate units start losing capacity around 17 degrees F
- Continues operating to -24 degrees F - keeps running through our worst cold snaps
- Up to 30.5 SEER cooling efficiency - outstanding summer performance too
Best Applications
Right fit when...
- Your home is under roughly 2,500 sq ft and you want fully electric heating (no gas backup)
- You don't have existing ductwork and want to avoid the $10,000-$20,000 cost of adding it
- You want zoned comfort with different temperatures in different rooms
- You're adding heating/cooling to a basement, addition, or garage conversion
Configuration Options
Indoor unit types
- Wall-mounted units - most common, visible but quiet
- Ceiling cassettes - flush-mount in ceiling, more discreet
- Floor-mounted units - good for rooms with limited wall space
- Ducted air handlers - connects to existing or new ductwork
Watch Out For
Not all Mitsubishi units are H2i. Standard Mitsubishi mini-splits are NOT cold-climate rated. We've seen contractors install regular Mitsubishi units and tell customers they're "cold climate." They're not. Look specifically for the H2i or Hyper-Heating designation.
Typical Cost
A 4-zone Mitsubishi H2i system for a 2,400 sq ft home runs approximately $29,000-$32,000 before rebates. After Xcel Energy, state, and HEAR rebates (if eligible), out-of-pocket can drop to $10,000-$16,000.
Bosch IDS Ultra: Best All-Arounder for Ducted Retrofits
The Bosch IDS Ultra is our go-to recommendation for homes with existing ductwork. We've installed over 600 of these systems, and the flexibility makes them ideal for retrofits.
Why It Works
Bosch engineered the IDS Ultra specifically for cold climates with an Enhanced Vapor Injection (EVI) compressor. The variable-speed inverter modulates in 1% increments, precisely matching your heating needs rather than cycling on and off.
IDS Ultra Cold-Weather Specs
- 100% heating capacity at 5 degrees F - holds strong through most Colorado winter nights
- Continues operating to -13 degrees F - covers our coldest temperatures
- R-454B refrigerant - already compliant with 2026 regulations, future-proofed
Configuration Flexibility
This is where Bosch differentiates. The IDS Ultra works with three configurations:
How it can be installed
- Air handler - heat pump outdoor unit + electric air handler. Fully electric, no gas needed.
- Furnace + coil - heat pump outdoor unit + existing or new gas furnace + evaporator coil. Dual-fuel setup for extreme cold backup.
- Coil-only - heat pump outdoor unit + evaporator coil only. Works with existing compatible air handlers.
Watch Out For
The IDS Ultra only comes in larger sizes (4-5 ton). If your home needs less capacity, typically under 2,000 sq ft, this may be more system than you need. Bosch is releasing a 3-ton IDS Ultra in 2026 that will expand options for smaller homes.
Typical Cost
A Bosch IDS Ultra system for dual-fuel (heat pump + furnace) runs approximately $25,000-$28,000 before rebates. After rebates, out-of-pocket can drop to $8,000-$16,000 depending on your rebate eligibility.
Carrier 37MUH: Solid Mid-Range Option
The Carrier 37MUH is a crossover cold-climate heat pump for ducted systems, delivering solid performance at a more accessible price point. We've installed about 80 of these systems with good results.
Why It Works
The 37MUH is manufactured by Midea and sold under the Carrier name. Some customers ask about this. Our take: it performs well. Carrier has a strict quality control process for the 37MUH and it has a solid track record in Colorado.
37MUH Cold-Weather Specs
- Operates down to -22 degrees F - solid cold-climate capability
- Up to 22 SEER cooling - efficient summer performance
- Variable-speed inverter compressor - quiet, efficient operation
Compared to Mitsubishi H2i
- Factor
- Low-temp capacity
- Mitsubishi H2i
- Better (100% at 5 degrees F)
- Carrier 37MUH
- Good (starts losing at 15 degrees F)
- Factor
- Efficiency
- Mitsubishi H2i
- Higher SEER ratings
- Carrier 37MUH
- Slightly lower
- Factor
- Track record
- Mitsubishi H2i
- 4,000+ CO installs
- Carrier 37MUH
- 80+ CO installs
- Factor
- Price
- Mitsubishi H2i
- Higher
- Carrier 37MUH
- Lower
Bottom line: If budget allows, Mitsubishi H2i is the superior ductless option. For ducted systems where cost matters, the 37MUH delivers.
Decision Framework: Which One Should You Choose?
Choose Mitsubishi H2i if
→Best cold-weather performance, no gas needed
Home under ~2,500 sq ft, want fully electric, no ductwork or ducts in poor condition, want zoned comfort, or willing to pay for the proven leader.
Choose Bosch IDS Ultra if
→Best ducted whole-home system
Existing ductwork in good condition, need flexible config (air handler, dual-fuel, or coil-only), home is 2,500+ sq ft, or want R-454B refrigerant now.
Choose Carrier 37MUH if
→Solid mid-range ducted option
Have ductwork but need to watch budget, want a crossover unit for whole-home ducted heating and cooling, and mid-range performance meets your needs.
Find Your Brand Match
Answer a few questions to see which system fits your situation best:
Find Your Brand
What matters most to you?
Select your top priority for choosing a heat pump brand.
What About Other Brands?
We focus on these three because they're the cold-climate heat pumps we trust in Colorado winters. We've tested other brands and found issues:
Brands We Avoid
- Daikin - Capacity issues and reliability problems in our climate
- Lennox - Frequent compressor failures
- Trane (new R454B models) - Too new, early experience not promising
- MrCool - DIY units not designed for real cold-climate performance
- Rheem - Breaks often, can't keep up in our climate
- Fujitsu multi-zone - Single-zone OK, multi-zone struggles
Why It Matters
- Our three recommended brands have the lowest callback rates across 12,000+ Colorado installs
- We'll tell you which system makes sense, even if that means recommending something outside this list
- All three recommended brands operate reliably at Denver-area altitude and cold temperatures
Colorado Rebates Apply to All Three
All three systems qualify for the same rebates. For the full rebate stacking guide, see our Xcel Energy HVAC rebates page and the HEAR rebates guide. To understand efficiency ratings (SEER2, HSPF2) for each system, see our efficiency ratings explained guide.
- Rebate
- Xcel Energy
- Amount
- $2,250/ton
- Who Qualifies
- Xcel gas customers
- Rebate
- State of Colorado
- Amount
- $1,000-$1,500
- Who Qualifies
- All Colorado residents
- Rebate
- HEAR
- Amount
- Up to $8,000
- Who Qualifies
- Households under 150% AMI
- Rebate
- Federal 25C (Ended)
- Amount
- Was 30% up to $2,000
- Who Qualifies
- Ended Dec 31, 2025
Getting Started
Not sure which system fits your home? Here's what happens when you contact us:
- We assess your home - Square footage, existing HVAC, ductwork condition, electrical capacity
- We recommend options - Usually 2-3 system configurations with pros/cons for your situation
- We show you real numbers - Equipment cost, installation cost, all applicable rebates calculated
- You decide - No pressure, take your time
We've installed over 12,000 heat pumps across the Denver metro. We'll tell you which system makes sense, even if that means recommending something we don't install.
Get a Quote on the Right System
Free estimate, honest recommendation, no pressure. We'll tell you which system fits your home.
