Foothill High-Efficiency Heat Pump Upgrade: Federal Heights Tudor Home

Customer:: Aaron M. (consent for documentation given)
Address area:: Federal Heights, Salt Lake City — upper foothill east bench, near University of Utah research park
Home characteristics:: 1927 Tudor Revival home, approximately 3,400 sq ft across two stories plus partially finished basement (~1,100 sq ft). Original brick exterior with wood-framed construction. Original lath-and-plaster walls in main living areas. Original wood floors throughout main level, refinished 2003. Single-pane wood double-hung windows (original) with custom storm windows added 2008. Foothill elevation: 4,840 ft. South-facing primary exposure with mature trees providing afternoon shade. Stone retaining wall and terraced landscaping on uphill side. Two-story stair-stepped floor plan creates significant temperature variation between floors.
Project type:: Full system replacement — furnace AND AC at end of life, customer evaluating heat pump conversion as alternative; two-zone retrofit added to address inter-floor temperature variation
Project completion date:: September 23, 2024
Total cost:: $24,800 installed plus $2,000 Rocky Mountain Power Wattsmart rebate + $2,000 IRA 25C heat pump tax credit = $20,800 net cost

Background

Aaron M. is a longtime customer with multiple service relationships across his Federal Heights properties. This case study documents the September 2024 full system replacement at his primary residence, the 1927 Federal Heights Tudor. The project replaced a 2002 mid-tier Carrier furnace and 1998 Carrier AC, both reaching end of expected service life. Aaron’s other Federal Heights property (a Penrose Drive home with Carrier 59TP6 modulating furnace + MERV 13 static pressure remediation, separate case study planned) gave him exposure to the value of premium modulating equipment. He also coordinated a 2-zone retrofit, outdoor kitchen gas line installation, and considered other upgrades during this consultation, but the primary project scope was furnace + AC end-of-life replacement.

Existing Equipment

Furnace (replaced):: 2002 Carrier 58STA050 furnace. 80,000 BTU/hr input, 80% AFUE. Natural gas. Located in basement utility area. Atmospheric venting through dedicated B-vent stack (separate from boiler-era brick chimney). 22 years service life at time of project — approaching average residential furnace life expectancy.
AC (replaced):: 1998 Carrier 38ARE024 split system AC. 2-ton capacity, 10 SEER (pre-SEER2 rating). 26 years service life. Refrigerant: R-22 (phase-out completed in 2020; R-22 no longer produced; existing inventory limited and expensive). Operating but increasingly inefficient and approaching point where refrigerant leaks would require equipment replacement rather than repair.
Ductwork:: Mixed vintage. Original 1927 ductwork in basement and main level (rectangular sheet metal, some original galvanized). 2002 modifications during previous furnace replacement (round trunk and branches in basement). Limited insulation on visible ducts. Manual D static pressure analysis identified significant pressure imbalance between first floor and second floor — root cause of temperature variation that motivated zoning consideration.
Thermostat:: Honeywell programmable (2008) on main floor near front entry. Single zone control across entire home — major source of comfort complaint (basement at 64°F while second floor at 78°F during summer afternoons).
Other:: 50-gallon natural gas water heater (separate venting). MERV 8 1-inch filter at return air. No active IAQ equipment.

Pre-Installation Assessment

Initial consultation (June 2024):

120-minute on-site consultation. Detailed discussion of customer priorities: (a) end-of-life equipment replacement, (b) reduce comfort variation between floors, (c) reduce operating costs, (d) consideration of heat pump conversion given AC end of life and 22-year-old furnace.

Manual J load calculation:

Total heating load: 68,400 BTU/hr at ASHRAE 99% winter design (5-6°F at Federal Heights elevation, slightly colder than valley floor)
Total cooling load: 36,200 BTU/hr at ASHRAE 1% summer design (95°F dry bulb at Federal Heights elevation)
Cooling-heating ratio: approximately 1:1.9 (heating dominant but cooling load significant for this larger home)

Altitude derate calculation (Federal Heights 4,840 ft):

Per IFGC Section 304.1, 19.4% derate at this elevation. Effective output reduction: any gas furnace nameplate capacity must be divided by 0.806 to determine actual heating capacity at elevation. This calculation applied during equipment selection.

Manual D ductwork analysis:

Static pressure at supply plenum: 0.78″ WC (excessive — should be 0.5-0.6″ for typical residential)
First-floor branches: adequate airflow (370 CFM total)
Second-floor branches: undersized for load (185 CFM vs. 280 CFM required)
Cause: original 1927 trunk and branches sized for boiler-era radiator system, not adequately sized for forced-air conversion

Two-zone retrofit feasibility:

Existing ductwork supports two-zone retrofit (first floor + basement / second floor) with damper actuator installation at trunk-to-branch transitions. Ductwork modifications: 4-6 hours for damper installation plus zone control wiring. Compatible with communicating control system on premium equipment.

Heat pump conversion economics analysis:

Aaron specifically requested detailed economic comparison of heat pump conversion vs. separate furnace + AC replacement.

Option	Initial Cost	Rebates/Credits	Net Cost	Annual Operating
Separate replacement (premium furnace + premium AC)	$26,400	$200 ThermWise + $1,200 IRA 25C + $1,200 Wattsmart = $2,600	$23,800	$1,820 (heating) + $640 (cooling) = $2,460
Premium heat pump conversion (Carrier Greenspeed)	$24,800	$2,000 Wattsmart + $2,000 IRA 25C = $4,000	$20,800	$1,420 (heating + cooling combined)
Savings with heat pump conversion	$1,600 lower initial	$1,400 more rebates	$3,000 lower net	$1,040 less operating per year

Conclusion of analysis:

Heat pump conversion presented better economics across all dimensions for Aaron’s situation. Primary remaining decision: confidence in cold-climate heat pump capability at Federal Heights’ 4,840 ft elevation with sub-design winter temperatures occasionally falling to 0-5°F.

Decision Framework

Heat pump equipment options evaluated:

Mid-tier cold-climate heat pump: Bosch IDS Premium 2.0 5-ton — $18,400 installed. NEEP CCASHP listed. Solid performance, mid-tier features.
Premium cold-climate inverter: Carrier Greenspeed 25VNA0 5-ton — $24,800 installed. NEEP CCASHP listed. Variable-capacity inverter (40-100% modulation), communicating with Carrier Infinity controls, 22 SEER2 / 11.0 HSPF2 rating. Selected option.
Premium cold-climate inverter alternative: Mitsubishi P-Series PUZ-HA60NKA 5-ton — $26,800 installed. Hyper-Heat H2i to -15°F. Slightly higher cost but proven cold-climate performance.
Daikin Aurora: 5-ton — $22,400 installed. NEEP CCASHP listed.

Customer selection:

Aaron selected Carrier Greenspeed 25VNA0. Reasoning: (a) integrates with Carrier Infinity communicating controls he already preferred from Penrose Drive property experience; (b) 22 SEER2 / 11.0 HSPF2 industry-leading efficiency at this capacity tier; (c) variable-capacity inverter modulation provides excellent part-load comfort matching modulating furnace experience; (d) NEEP CCASHP listed equipment qualifies for full $2,000 IRA 25C heat pump tax credit and $2,000 Wattsmart rebate.

Heat strip backup:

15kW electric resistance heat strip integrated with indoor air handler for supplemental heat during sub-design conditions. NEEP CCASHP listed Carrier Greenspeed maintains 80%+ heating capacity at 5°F outdoor, but heat strips provide capacity assurance during rare sub-5°F events.

Equipment Specifications

Outdoor heat pump: Carrier Greenspeed 25VNA0

Model: 25VNA060A0 (5-ton, 60,000 BTU/hr nominal cooling capacity)
Variable-capacity inverter (40-100% modulation)
22 SEER2 / 11.0 HSPF2
NEEP CCASHP listed cold-climate heat pump
R-410A refrigerant
Carrier Infinity communicating control compatible
Operates effectively to -10°F outdoor (continued operation, declining capacity)
10-year parts warranty, 10-year compressor warranty

Indoor air handler: Carrier FE5A

Model: FE5ANF005 (matched 5-ton air handler)
Variable-speed ECM blower
15kW electric heat strip integrated for supplemental heat
MERV 13 cabinet integration support
Located in basement utility area (replacing existing furnace location)

Two-zone retrofit:

Honeywell Truezone HZ322 zone control board
Two damper actuators (Belimo TruZone) at trunk-to-branch transitions
Two communicating thermostats: Carrier Infinity Touch Control 8″ wall display (main floor) and Honeywell T10 Pro (second floor)
Zone 1: first floor + basement (370 CFM design)
Zone 2: second floor (280 CFM design with damper-controlled distribution)

IAQ integration:

AprilAire 213 4-inch MERV 13 filter cabinet replacing original 1-inch MERV 8 housing. Compatible with premium variable-speed blower without excessive static pressure increase.

Refrigerant lines:

3/8″ liquid line, 7/8″ suction line copper. Approximately 38 ft total length (basement-to-yard run + horizontal distance to condenser location). Refrigerant: 8.4 lbs R-410A (factory charge + line set charge per manufacturer specifications).

Electrical:

Existing 200A service. New 60A 240V dedicated circuit for outdoor heat pump unit. Separate 60A 240V circuit for indoor air handler with heat strip. Total new circuits: 2 (120A combined). Service capacity verified adequate. Subpanel upgrade not required.

Installation Scope and Timeline

Day 1 (September 19, 2024):

Equipment delivery and staging
Existing furnace removal and disposal
Existing AC condenser removal and proper R-22 refrigerant reclamation (EPA Section 608 compliance)
Existing evaporator coil removal
Site preparation for new equipment

Day 2 (September 20, 2024):

Outdoor heat pump condenser placement on new concrete pad (north side of home, sheltered from south-facing solar gain)
Refrigerant line set installation (basement-to-yard run through east foundation wall)
Electrical work (two new 60A 240V circuits, outdoor disconnect, indoor disconnect)
Indoor air handler installation
Condensate drain installation

Day 3 (September 21, 2024):

Ductwork modifications for two-zone retrofit
Damper actuator installation at trunk-to-branch transitions
Zone control board installation
Communicating thermostat installation (main floor)
Honeywell T10 Pro installation (second floor)
Manual D measurements post-modification

Day 4 (September 22, 2024):

AprilAire 213 MERV 13 filter cabinet installation
Refrigerant line connection and brazing
System evacuation (24-hour deep vacuum to 250 microns)
Refrigerant charge per manufacturer specification
Carrier Infinity controls commissioning and configuration
Zone calibration and balance
Customer education on system operation, smart controls, zoning logic

Day 5 (September 23, 2024):

Final commissioning measurements
Performance verification across all operating modes (cooling, heating, defrost, emergency heat)
Salt Lake City Building Department inspection (passed)
Final paperwork and customer education

Commissioning measurements (after installation):

Cooling subcooling: 10°F (Carrier specification: 8-12°F)
Cooling superheat: 12°F (Carrier specification: 10-15°F)
Heating mode supply temperature: 102°F at 38°F outdoor (typical for heat pump heating mode)
Refrigerant charge: 8.4 lbs R-410A
Cooling supply air temperature differential: 19°F (excellent performance)
Total system airflow: 2,000 CFM (Manual J calculation for 5-ton system at altitude)
Static pressure at supply plenum: 0.52″ WC (significant improvement from 0.78″ pre-modification)
Zone calibration: Both zones reaching setpoint within 12 minutes of system start

AHJ inspection:

Salt Lake City Building Department inspection September 23, 2024. Passed inspection. Permit documentation: Salt Lake City permit #B-2024-22398.

Cost Breakdown

Itemized project cost:

Carrier Greenspeed 25VNA0 outdoor heat pump: $8,400
Carrier FE5A indoor air handler with heat strip: $2,200
Heat pump + air handler installation labor: $4,400
Refrigerant line set materials and installation: $585
R-410A refrigerant: $336 (8.4 lbs at $40/lb)
Existing R-22 refrigerant reclamation: $185 (EPA compliance)
Carrier Infinity Touch Control thermostat: $585
Honeywell T10 Pro communicating thermostat: $385
Honeywell HZ322 zone control board: $585
Belimo TruZone damper actuators (2): $640
Zone retrofit installation labor: $1,200
Electrical work (2 new 60A circuits, disconnects): $1,400
Concrete pad for outdoor unit: $245
AprilAire 213 MERV 13 filter cabinet: $385
Condensate drain modification: $185
Permit fees: $385
System commissioning: $385
Subtotal: $22,505
Premium Care plan member 20% discount: $0 (Aaron upgraded to Premium Care during this project, took effect after installation)
Project complexity adjustment: $2,295 (heat pump conversion + two-zone retrofit + ductwork modifications)
Total customer cost: $24,800 installed

Rebates and incentives:

Rocky Mountain Power Wattsmart rebate (cold-climate heat pump NEEP CCASHP listed, 5-ton): $2,000
Federal IRA 25C heat pump tax credit: 30% of qualifying heat pump cost ($8,400 + $2,200 = $10,600) up to $2,000 cap = $2,000 (capped)
Dominion Energy ThermWise: not applicable for heat pump (program covers high-efficiency natural gas equipment)

Net out-of-pocket cost:

$24,800 – $2,000 Wattsmart = $22,800 after rebate. Federal tax credit additional $2,000 reduction at 2024 tax filing. Final net cost: $20,800.

Post-Installation Outcomes

Winter 2024-2025 heating performance (full season data):

Heat pump primary heat across all but coldest 6 nights (sub-0°F)
Heat strip activation: estimated 47 hours total across winter season (typically 1-3 hour periods during early morning cold)
Electric bill increase from heat pump operation: +$140/month average across November-March
Gas bill reduction (eliminated furnace heating): -$210/month average across same period
Net monthly heating bill: -$70/month reduction (heat pump heating cheaper than gas furnace)
Full season heating cost: $1,420 (vs. estimated $1,820 with replacement gas furnace)

Summer 2025 cooling performance:

Variable-capacity modulation provides better part-load humidity control than previous fixed-speed equipment
Two-zone retrofit eliminated comfort variation between floors. Both zones maintain independent setpoints.
Electric bill increase from cooling operation: +$67/month average (significantly lower than pre-installation R-22 equipment)
Full season cooling cost: $268 (vs. estimated $640 with replacement R-410A AC)

Annual operating cost analysis:

Pre-installation annual heating + cooling: $3,840
Post-installation annual heating + cooling: $1,688
Annual savings: $2,152
Payback period on initial project cost: ~9.7 years (without rebates)
Payback period after rebates: ~5.4 years

Comfort improvements (customer-reported):

Two-zone retrofit transformed the temperature variation problem. Aaron reported the second-floor primary bedroom maintained 70°F overnight setpoint independently of basement zone. Variable-capacity inverter modulation provides notably quieter operation and better humidity control during cooling. Carrier Infinity controls integration with home automation provides usage data and smart scheduling.

Heat pump cold-weather performance:

Aaron specifically tracked heat pump capacity during sub-design winter conditions. Confirmed: heat pump maintained 80%+ heating capacity at 5°F (matching manufacturer specification). Heat strip activated only during 6 sub-zero overnight events; total heat strip operation: 47 hours across full season. Manufacturer cold-climate rating validated by actual operation.

Aaron’s overall assessment:

“The combination of operating cost reduction, comfort improvement, and two-zone temperature control significantly exceeded my expectations. The heat pump conversion economics were better than I expected even before rebates.” Aaron plans to use this project as template for evaluating heat pump conversion at his other Federal Heights properties as their existing equipment reaches end of life.

Ongoing service relationship:

Aaron upgraded to Premium Care plan effective post-installation. Plan benefits: annual tune-up (combined spring AC + fall heat pump testing), 20% repair discount, 1-hour priority dispatch, waived diagnostic fees, IAQ measurement included. First annual tune-up: April 2025.

Code Compliance Documentation

Applicable codes for this project:

2024 IMC with Utah amendments: Mechanical equipment installation
ACCA Manual J: Heating and cooling load calculation (68,400 BTU/hr heating, 36,200 BTU/hr cooling)
ACCA Manual S: Equipment selection (5-ton heat pump appropriately sized)
ACCA Manual D: Ductwork analysis (modifications addressed pressure imbalance)
ACCA Manual N (zoning): Two-zone design protocol
ASHRAE 52.2: MERV 13 testing standard
NEC Article 440: Air-conditioning and refrigerating equipment
NEC 240.21(C): Outdoor disconnect requirements
2021 IECC: Energy efficiency requirements (22 SEER2 / 11.0 HSPF2 significantly exceeds minimum)
EPA Section 608: Refrigerant handling (R-22 reclamation from existing equipment, R-410A handling on new equipment)
NEEP CCASHP: Cold-climate heat pump specification (Carrier Greenspeed 25VNA0 listed)
IFGC Section 304.1: Not directly applicable to electric heat pump (no gas equipment), but altitude effect noted on indoor air density

Permit number:

Salt Lake City Building Department permit #B-2024-22398

Permit issuance:

September 13, 2024

Inspection passed:

September 23, 2024

Frequently Asked Questions

Does heat pump heating actually work at Federal Heights elevation?: Yes — with proper equipment selection. NEEP CCASHP-listed cold-climate heat pumps (Carrier Greenspeed, Mitsubishi P-Series H2i, Daikin Aurora, Bosch IDS Premium 2.0) are specifically designed for cold climate operation. Carrier Greenspeed maintains 80%+ heating capacity at 5°F outdoor and continues operating to -10°F. Salt Lake’s ASHRAE 99% winter design is 9°F — well within Carrier Greenspeed’s full-capacity range. Aaron’s first winter operating data confirmed the manufacturer specification: 47 total heat strip hours across the season.
Why did heat pump conversion economics work better than expected?: Three factors combined. First, federal IRA 25C heat pump credit up to $2,000 is double the gas furnace credit ($1,200). Second, Rocky Mountain Power Wattsmart rebate is $2,000 for cold-climate heat pumps vs. $400-$1,200 for AC. Third, eliminating gas furnace operating costs (heat pump heating cheaper than gas at current rates) creates immediate operating savings. Combined rebate stack alone ($4,000) covers more than 15% of project cost.
Why two-zone retrofit instead of separate equipment per floor?: Cost-effective approach. Single heat pump system with two-zone control via damper actuators delivers independent setpoint capability to first floor and second floor at $2,400 retrofit cost. Two separate heat pump systems would have cost $14,000+ additional (separate outdoor units, separate air handlers, separate refrigerant lines). Two-zone retrofit achieves 95% of the comfort benefit at 17% of the additional cost.
What about premium ductwork modifications?: Manual D analysis identified the original 1927 ductwork pressure imbalance as root cause of inter-floor temperature variation. Modifications during installation included: second-floor branch upsizing, damper actuator installation at trunk transitions, return air path improvements. Net effect: static pressure reduced from 0.78″ to 0.52″, second-floor airflow increased from 185 CFM to 290 CFM. Two-zone control combined with these ductwork improvements addressed the root cause rather than just managing symptoms.
How long until the project pays back?: Without rebates: approximately 9.7 years on operating cost savings alone (project cost $24,800 / annual savings $2,152). After rebates: approximately 5.4 years on net cost $20,800. This doesn’t include comfort improvement value, which Aaron rated very highly but is difficult to quantify financially. Equipment expected service life: 18-22 years, meaning operating cost savings beyond payback period total approximately $26,000+ over equipment lifetime.

Project Details Summary

Customer:: Aaron M. (longtime customer, multiple Federal Heights properties)
Property:: Federal Heights 1927 Tudor Revival home, 3,400 sq ft, foothill elevation 4,840 ft
Project:: Heat pump conversion (replacing 2002 Carrier furnace + 1998 R-22 Carrier AC) plus two-zone retrofit plus MERV 13 IAQ upgrade
Completion date:: September 23, 2024
Total cost:: $24,800 installed, $22,800 after Wattsmart rebate, $20,800 net after federal tax credit
Equipment installed:: Carrier Greenspeed 25VNA060A0 5-ton heat pump (22 SEER2 / 11.0 HSPF2 NEEP CCASHP listed), Carrier FE5ANF005 air handler with 15kW heat strip, Honeywell HZ322 zone control with Belimo TruZone damper actuators, Carrier Infinity Touch Control + Honeywell T10 Pro thermostats, AprilAire 213 MERV 13 filter cabinet
Outcome:: Annual heating + cooling operating cost reduced from $3,840 to $1,688 ($2,152 annual savings). Two-zone temperature control eliminated inter-floor variation. 5.4-year payback period after rebates. Heat pump confirmed effective for Federal Heights elevation through 47 heat strip hours total winter 2024-2025.
Ongoing service relationship:: Premium Care plan member effective post-installation. First annual tune-up April 2025. Project being used as template for evaluation at Aaron’s other Federal Heights properties.

Schedule Your Heat Pump Conversion Consultation

Phone: (385) 300-1867
Address: 756 E Winchester St #322, Salt Lake City, UT 84107
Email: info@saltlakecityheatingairconditioning.xyz
Utah DOPL HVAC Contractor License: #11567823-5501
EPA Section 608 Universal (Lead Tech): #608U-2009-447129

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Foothill High-Efficiency Heat Pump Upgrade Case Study