Before and after
A West Valley City customer in a 1998-built two-story home approached us about replacing their aging gas furnace and AC with a heat pump system. Both pieces of equipment were original to the home — 26 years old at the time of inquiry — and the customer was researching options ahead of failure rather than waiting for a winter emergency. They were specifically interested in heat pump options because of the federal 25C tax credit (up to $2,000), and operating cost considerations.
This case study documents the complete heat pump conversion process from initial consultation through commissioning, including the rebate paperwork.
Customer Situation
- Home: 1998-built two-story, approximately 2,150 sq ft
- Existing equipment: 80% AFUE Goodman gas furnace, 80,000 BTU input; matching 3-ton R-22 AC; both 26 years old, original installation
- Existing condition: Both pieces operational but aging; AC making unusual compressor noises; furnace had increasing minor service calls
- Customer priorities: Replace before failure (planned vs. emergency), consider heat pump options, maximize available incentives
- Income qualification: Household income within 80% of area median, qualifying for IRA Home Electrification full rebate level
Equipment Selection Discussion
Three options reviewed:
Option 1: Like-for-like gas furnace + AC replacement — $11,500 installed – 96% AFUE single-stage furnace – Standard single-stage AC – Familiar technology, no electrical work needed – Federal 25C credit: $600 furnace + $600 AC = $1,200 maximum
Option 2: Dual-fuel system (heat pump + gas furnace backup) — $17,200 installed – Two-stage heat pump primary – Gas furnace for severe cold backup – Heat pump efficiency in mild/moderate weather – Federal 25C credit: $2,000 heat pump + $600 furnace – Rocky Mountain Power heat pump rebate: $400 – IRA Home Electrification not qualifying (mixed-fuel system)
Option 3: All-electric variable-speed heat pump — $18,800 installed – Cold-climate variable-speed heat pump – Auxiliary electric heat strips for severe cold (15kW) – Eliminates gas service if customer wants – Federal 25C credit: $2,000 – Rocky Mountain Power heat pump rebate: $400 –
Customer selected Option 3 (all-electric variable-speed heat pump).
Manual J Load Calculation
On-site load calculation:
- Conditioned area: 2,150 sq ft two-story
- Insulation: R-13 walls, R-30 attic (1998 construction)
- Windows: 245 sq ft vinyl double-pane (original)
- Salt Lake design conditions: 14°F heating / 96°F cooling
Manual J results: – Heating load: 42,000 BTU/h at 14°F design temperature – Cooling load: 26,800 BTU/h (2.25 tons)
Equipment Selected
Trane XV20i 4 ton variable-speed heat pump system:
- Outdoor unit: Trane 4TWV0048 variable-speed heat pump
- Indoor air handler: Trane TAM9 variable-speed
- Heat strips: 15kW backup electric heat
- Smart thermostat: Trane XL824 with proper balance point and staging configuration
- 12-year parts warranty, lifetime compressor warranty (registered)
Selection rationale:
- Variable-speed cold-climate heat pump maintains capacity at 14°F design temperature
- 4-ton sizing covers heating load with reasonable margin; cooling capacity provides modulation across the 2.25-ton actual cooling load
- 15kW heat strips provide auxiliary capacity for severe cold events below design temperature
- Matched system supports proper modulation through communicating control
Electrical Service Verification
Critical step for heat pump conversion — verify electrical service capacity:
- Existing service: 200 amp panel (1998 construction standard)
- Existing load: Approximately 110 amps connected load (calculated)
- New heat pump compressor: 16 amps at 240V
- Auxiliary heat strips: 65 amps at 240V (15kW)
- Total addition with strips operating: 81 amps
- New service load: 110 + 81 = 191 amps (within 200 amp service)
Electrical service capacity adequate without upgrade. Required: new 240V dedicated circuits for heat pump (40 amp) and heat strips (90 amp).
Electrical work performed by licensed electrician under coordinated scheduling.
Installation
Duration: 2 days
Day 1: – Old equipment removal (R-22 recovery per EPA, gas line capped per plumbing requirements) – New air handler installation – Heat strip installation in air handler – Refrigerant line set installation (R-410A compatible) – Condensate drainage – Electrical work (240V circuits, electrical disconnect, equipment connections) – Smart thermostat installation and basic configuration
Day 2: – Outdoor unit placement on existing concrete pad (verified pad condition) – Refrigerant connections with nitrogen purge during brazing – System evacuation to 425 microns held 30 minutes – Refrigerant charge by weight per manufacturer specification – Smart thermostat full configuration (heat pump operation, balance point, staging, communicating system) – Final commissioning measurements
Commissioning Measurements
Cooling mode test: (outdoor 78°F) – Suction pressure: 132 psi ✓ – Discharge pressure: 285 psi ✓ – Subcool: 9°F ✓ – Indoor temperature differential: 19°F ✓ – Compressor amp draw (1st stage): 5.8 amps; (full stage): 14.2 amps ✓
Heating mode test: (outdoor 78°F — limited because of mild weather, full testing planned during cold weather follow-up) – Reverse valve operation: confirmed – Heat pump heating output: confirmed – Auxiliary heat strip activation tested independently (proper sequencing confirmed) – Defrost cycle simulated test: nominal operation
Smart thermostat configuration: – Equipment type: variable-speed heat pump with auxiliary heat – Balance point: 25°F (auxiliary heat assists below this temperature) – Compressor lockout: 5°F (below this, auxiliary heat only) – Wi-Fi connectivity established for remote monitoring
Cold Weather Follow-Up
Customer scheduled cold-weather follow-up visit in January after first sustained cold spell:
- Outdoor temperature during visit: 11°F
- Heat pump operating in stage 2 (high capacity)
- Auxiliary heat activated as designed below 25°F balance point
- Indoor temperature: 70°F maintained at setpoint
- Heat pump output verified: 31,400 BTU/h at 11°F (manufacturer spec at conditions)
- Aux heat strips delivering additional 51,200 BTU/h (15kW)
- Total system capacity: 82,600 BTU/h at 11°F — well above 42,000 BTU/h design load
Customer reported indoor temperature stable through coldest 2-day cold snap (low of -2°F overnight).
Final Cost and Rebate Filing
Customer’s project cost: – Equipment and installation: $18,800 – Electrical work (240V circuits, dedicated electrician invoice): $1,650 – Total: $20,450
Rebates and credits filed: – Federal 25C tax credit: $2,000 (customer claims on tax return) – Rocky Mountain Power Wattsmart heat pump rebate: $400 (mailed to customer) – IRA Home Electrification rebate: $8,000 (income-qualified, application processed through state program)
Effective net cost after all incentives: $10,050
The federal tax credit and the Rocky Mountain Power Wattsmart rebate reduced the customer’s net cost.
Customer Outcome
Six-month operational data (winter heating season): – Average winter electric bill: $185/month (heating + base load) – Prior year comparison (gas furnace + AC): $95 electric + $145 gas = $240/month average – Net monthly savings: ~$55/month winter – Indoor comfort consistent across home – No supplemental heating sources needed
Summer follow-up (subsequent year): – Variable-speed cooling provides excellent dehumidification – Stage 1 operation handles most cooling demand quietly and efficiently – Average summer electric bill: $185/month (cooling + base load) – Prior year comparison: $215/month with old AC – Net summer savings: ~$30/month
Total estimated annual savings vs. original equipment: $1,000+/year
What This Case Study Demonstrates
- IRA Home Electrification rebates are real — $8,000 income-qualified rebate fundamentally changes heat pump economics for qualifying households
- Variable-speed cold-climate heat pumps work in Salt Lake winter — 11°F operation confirmed; -2°F overnight handled with auxiliary heat assistance
- Electrical service verification matters — 200-amp service was adequate but required calculation; 100-amp service would have required upgrade
- Documented commissioning across modes — cooling commissioned immediately, heating verified during cold weather follow-up
- Realistic savings expectations — $1,000+/year savings is significant but not the unrealistic claims some marketing makes
- Right equipment for the situation — all-electric variable-speed appropriate for income-qualified customer; dual-fuel might have been better for non-qualifying customer
Considering a Heat Pump Conversion?
If you’re researching heat pump options in West Valley City, contact us or call (385) 250-0687. We perform Manual J load calculations, verify electrical service capacity, model all available incentives (Federal 25C, Rocky Mountain Power Wattsmart, Enbridge Gas ThermWise (formerly Dominion Energy)), and provide written quotes with rebate-adjusted net cost analysis.
- Phone: (385) 250-0687
- Address: 4454 Manhattan Ct, West Valley City, UT 84120
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