Downtown Condo Ductless Mini-Split Install Case Study

Downtown Salt Lake City Condo Ductless Mini-Split Installation

Customer:
Naomi B. (consent for documentation given)
Address area:
Downtown Salt Lake City — 1907 brick warehouse converted to condos in 2008, near West Temple
Home characteristics:
1,180 sq ft single-level condo on third floor (top floor) of converted brick warehouse. Two bedrooms, one bathroom, open-plan main living area. Original exposed brick walls (south and west exterior walls retained), drywall on partition walls. Original wood floors refinished during 2008 conversion. Concrete deck floor with 2008-installed gypcrete topping. Existing electric baseboard heat (original to 2008 conversion). No existing AC. South-facing exposure with significant solar gain during summer afternoons. North-facing primary bedroom windows.
Project type:
Ductless mini-split installation (cooling and heating); single-zone configuration with one outdoor condenser and one indoor head
Project completion date:
April 22, 2025
Total cost:
$7,800 installed plus $400 Rocky Mountain Power Wattsmart rebate = $7,400 net cost (federal IRA 25C tax credit additional $2,000 reduction at tax filing — heat pump credit)

Background

Naomi B. purchased her downtown condo in 2022. The 2008 conversion installed electric baseboard heat throughout but did not include any cooling capability. For three summers Naomi used a portable AC unit vented through a window (with the typical compromises of portable ACs: noisy operation, limited cooling capacity, condensate management hassle). The 2025 project addressed both the inadequate cooling and the high electric heating bills from the baseboard heat. Naomi initially inquired about adding refrigerated AC; consultation expanded the scope to a heat pump mini-split that would serve as both cooling AND primary heating (with the baseboard heat as backup for the coldest weather), significantly reducing winter electric bills.

Existing Equipment and Constraints

Heating (existing, kept as backup):
Cadet electric baseboard heaters on each room’s exterior wall. Total installed capacity: approximately 6,000 W (20,500 BTU/hr). Operational and in good condition, but expensive to operate (electric resistance heat). Standard 240V circuits to each baseboard heater.
Cooling (existing, removed):
Portable AC unit vented through living room window. 10,000 BTU/hr nameplate capacity (actual cooling capacity significantly less due to single-hose configuration). Removed by Naomi prior to installation.
Electrical:
100A service panel original to 2008 conversion. Available capacity for new 30A 240V mini-split circuit confirmed during initial consultation. No service upgrade required.
HOA constraints:
Significant. The HOA bylaws restrict exterior modifications to the building. Specific HOA approval required for: outdoor condenser placement, refrigerant line set routing through exterior brick wall, exterior condenser visibility from the street.
Brick wall considerations:
Original 1907 brick exterior wall (multi-wythe brick, approximately 12″ thick). Penetration for refrigerant line set required core drilling. Customer arranged with HOA-approved masonry contractor for wall penetration and post-installation patching. Coordinated with our installation crew for scheduling.
Condenser placement options:
Limited. Most viable location: small concrete ledge on south-facing exterior wall at second-floor level (deck area shared with Naomi’s neighbor). HOA approval required and granted (with conditions: paint condenser unit to match brick color, screen behind decorative grate, height limitation).

Diagnostic Findings and Pre-Installation Assessment

Initial consultation (February 2025):
90-minute on-site consultation. Detailed discussion of HOA constraints, customer priorities (efficient cooling + heating cost reduction), aesthetic considerations (exposed brick walls in main living area), and equipment options.
Manual J load calculation:
  • Total cooling load: 14,200 BTU/hr at ASHRAE 1% summer design (96°F at downtown elevation 4,226 ft)
  • Total heating load: 18,800 BTU/hr at ASHRAE 99% winter design (9°F)
  • Cooling-heating load not equal — heating dominant. Equipment selection driven by heating load (18,000 BTU/hr capacity at design conditions).
Solar gain consideration:
South and west-facing exterior walls (exposed brick) and west-facing windows create significant afternoon solar gain. Manual J calculation accounted for this. Heat pump head placement chose central living area location for best cooling distribution to highest-gain areas.
Aesthetic considerations:
Customer prioritized minimal visual impact on exposed brick wall aesthetic. Wall-mounted indoor head selected (vs. ceiling cassette which would have required ceiling work). Indoor head positioned on partition drywall rather than exposed brick. White Mitsubishi finish matches partition wall.
Refrigerant line routing:
Designed to minimize visible line set inside the condo. Routing: from indoor head, through partition wall cavity (drywall) to exterior brick wall, through brick wall via masonry penetration, down exterior wall (painted to match brick) to ground-level condenser. Approximately 18 ft total line length.

Decision Framework

Equipment selection options evaluated:
  1. Cost-conscious mini-split: Senville LETO 18,000 BTU/hr — $5,400 installed. Adequate for the load but lower SEER2 rating and shorter expected equipment life.
  2. Mid-tier mini-split: Daikin Comfort 18,000 BTU/hr — $6,800 installed. Better performance, longer warranty.
  3. Premium cold-climate mini-split: Mitsubishi MUZ-FS18NA H2i Hyper-Heat 18,000 BTU/hr — $7,800 installed. Cold-climate rated for operation down to -15°F, qualifies for full $2,000 IRA 25C heat pump tax credit (vs. lower-tier mini-splits not always qualifying), best winter heating performance.
  4. Multi-zone mini-split: Mitsubishi MXZ multi-zone with two indoor heads — $11,400 installed. Considered but Naomi’s open-plan layout meant single zone adequate; two heads not needed.
Customer selection:
Naomi selected premium cold-climate Mitsubishi MUZ-FS18NA. Reasoning: (a) cold-climate H2i Hyper-Heat rated for operation down to -15°F (compared to Salt Lake’s 9°F winter design), meaning heat pump handles all Salt Lake winter conditions effectively; (b) NEEP CCASHP listing makes equipment eligible for full $2,000 IRA 25C federal tax credit (heat pump tier); (c) significantly higher HSPF2 means lower electric heating costs vs. baseboard; (d) equipment investment amortized over expected 18-22 year service life.

Equipment Specifications

Outdoor condenser: Mitsubishi MUZ-FS18NAH
  • Model: MUZ-FS18NAH (18,000 BTU/hr cooling, 21,600 BTU/hr heating at 47°F outdoor, 16,800 BTU/hr at 17°F outdoor)
  • 20.2 SEER2 / 11.0 HSPF2
  • H2i Hyper-Heat technology — rated to deliver 100% heating capacity down to 5°F outdoor, continued operation to -15°F
  • R-410A refrigerant (pre-2025 production)
  • Variable-capacity inverter compressor
  • NEEP CCASHP listed
  • 10-year parts warranty, 7-year compressor warranty
Indoor head: Mitsubishi MSZ-FS18NA
Wall-mounted indoor head, 18,000 BTU/hr capacity matched to outdoor condenser. White finish. kumo cloud connectivity for smart control. Quiet operation (19 dB on lowest fan speed).
Refrigerant lines:
1/4″ liquid line, 1/2″ suction line copper. Approximately 18 ft total length. Insulated with 1/2″ closed-cell foam (Armaflex). Refrigerant: 2.4 lbs R-410A (factory charge adequate for this line length).
Electrical:
New 30A 240V dedicated circuit from existing 100A service panel. Outdoor disconnect at condenser location.
kumo cloud / smart thermostat:
Mitsubishi kumo cloud Wi-Fi adapter and mobile app. Allows remote temperature control, scheduling, energy usage monitoring. Naomi opted in to enable smart scheduling.

Installation Scope and Timeline

HOA approval process (February-March 2025):
4 weeks for HOA approval. Submitted: exterior modification request, condenser placement plan, refrigerant line routing diagram, masonry penetration plan with HOA-approved contractor. HOA conditions imposed: condenser painted to match brick color, decorative grate screening from street view, masonry contractor must use lime-based mortar for patching (historic preservation requirement).
Pre-installation coordination (April 1, 2025):
Site visit with HOA-approved masonry contractor. Confirmed brick wall penetration location, planned core drilling sequence, scheduled installation crew arrival.
Day 1 (April 21, 2025):
  • Masonry contractor core-drilled 3-inch hole through 12″ brick wall
  • Outdoor condenser placement on south-facing concrete ledge
  • Refrigerant line set installation through brick wall penetration
  • Indoor head mounting on partition wall
  • Electrical work (new 30A 240V circuit, outdoor disconnect)
  • Condensate drain to existing kitchen sink drain (gravity drain — condenser positioned higher than drain)
Day 2 (April 22, 2025):
  • Masonry contractor patched brick wall penetration with lime-based mortar (per HOA requirement)
  • Refrigerant line connection and brazing
  • System leak check, evacuation, refrigerant charge verification
  • kumo cloud Wi-Fi adapter configuration
  • Customer education on operation, mobile app, scheduling
  • Commissioning measurements
Commissioning measurements (after installation):
  • Cooling subcooling: 8°F (manufacturer specification: 7-12°F)
  • Cooling superheat: 11°F (manufacturer specification: 8-15°F)
  • Refrigerant charge: 2.4 lbs R-410A (factory charge)
  • Cooling supply air temperature differential: 16°F at 65% relative humidity (typical for mini-split operation)
  • Heating mode operation verification: 21,200 BTU/hr at 38°F outdoor (April commissioning day) — within manufacturer specification
AHJ inspection:
Salt Lake City Building Department inspection April 25, 2025. Passed inspection. Permit documentation: Salt Lake City permit #B-2025-11042.

Cost Breakdown

Itemized project cost:
  • Mitsubishi MUZ-FS18NAH outdoor condenser: $2,800
  • Mitsubishi MSZ-FS18NA indoor head: $1,200
  • Mitsubishi kumo cloud Wi-Fi adapter: $185
  • Installation labor (2 days): $1,800
  • Refrigerant line set materials and installation: $385
  • R-410A refrigerant: $96 (2.4 lbs at $40/lb)
  • Electrical work (new 30A 240V circuit, outdoor disconnect): $385
  • Masonry contractor coordination (separate invoice): $385 (HOA-approved masonry contractor billed Naomi directly $785; we coordinated)
  • HOA approval coordination and documentation: $185
  • Decorative grate screening (HOA condition): $245
  • Permit fees: $185
  • System commissioning: $185
  • Subtotal: $8,034
  • (No existing plan discount — new customer; signed up for Premium Care plan after installation)
  • Project complexity adjustment (downward): -$234
  • Total customer cost: $7,800 installed (excluding $785 masonry contractor billed directly)
Rebates and incentives:
  • Rocky Mountain Power Wattsmart rebate (cold-climate heat pump NEEP CCASHP listed): $400
  • Federal IRA 25C heat pump tax credit: 30% of qualifying heat pump cost ($2,800 + $1,200 = $4,000) up to $2,000 cap = $1,200 actually claimed (limited by 30% of qualifying cost rather than $2,000 cap for this equipment cost)
Net out-of-pocket cost:
$7,800 – $400 Wattsmart = $7,400 net cost after rebate. Federal tax credit additional $1,200 reduction at 2025 tax filing. Effective cost: $6,200 + $785 masonry = $6,985 total project cost.

Post-Installation Outcomes

Summer 2025 cooling performance:
  • Whole-condo cooling vs. portable AC point-cooling. Open-plan main living area maintains consistent 72-74°F across all hours.
  • Primary bedroom (north-facing, naturally cooler) maintains 70-72°F.
  • Significantly quieter than portable AC (19 dB on low speed vs. 65+ dB for portable).
  • No more window blockage from portable AC venting hose.
  • No condensate management hassle.
Winter 2025-2026 heating performance (preliminary, partial season):
  • Heat pump operates as primary heat across all but the coldest nights (sub-15°F).
  • Electric baseboard heaters kept as backup but rarely needed (estimated 5-8 nights per winter).
  • Electric bill reduction: $185/month average reduction November 2025 – February 2026 vs. previous winter (baseboard heat only). Annualized estimated savings: $1,400-$1,800.
kumo cloud usage:
Naomi uses smart scheduling extensively. Setback to 60°F during weekday work hours (away from home), ramp to 70°F by evening. Weekend custom schedule. Energy usage monitoring shows actual operating cost typically 40-60% lower than baseboard-only operation.
HOA outcome:
HOA satisfied with installation. Painted condenser blends with brick aesthetic. Decorative grate screens from street view. Lime-mortar masonry patching nearly invisible. Naomi has reported other condo owners in the building have inquired about her installation; potential template for future HOA-approved mini-split installations in the building.
Naomi’s overall assessment:
“The cooling performance alone justified the project. The winter heating bill savings are a substantial bonus.” Project payback period (energy savings only, not counting comfort improvements): approximately 4-5 years.
Ongoing service relationship:
Naomi signed up for Premium Care plan after installation. Plan benefits: annual tune-up, 20% repair discount, 1-hour priority dispatch, waived diagnostic fees, IAQ measurement included. First annual tune-up: April 2026.

Code Compliance Documentation

Applicable codes for this project:
  • 2024 IMC with Utah amendments: Mechanical equipment installation
  • ACCA Manual J: Cooling and heating load calculation (14,200 BTU/hr cooling, 18,800 BTU/hr heating)
  • ACCA Manual S: Equipment selection (18,000 BTU/hr nameplate appropriately sized for heating-dominant load)
  • NEC 240.21(C): Outdoor disconnect requirements (compliant)
  • NEC Article 440: Air-conditioning and refrigerating equipment (compliant)
  • 2021 IECC: Energy efficiency requirements (20.2 SEER2 / 11.0 HSPF2 exceeds minimum significantly)
  • EPA Section 608: Refrigerant handling (lead technician EPA 608 Universal certified)
  • NEEP CCASHP: Cold-climate heat pump specification (Mitsubishi MUZ-FS18NAH listed)
  • Salt Lake City historic district guidelines: Brick wall penetration protocols (lime-based mortar patching, minimal visible exterior modifications)
Permit number:
Salt Lake City Building Department permit #B-2025-11042
Permit issuance:
April 15, 2025
Inspection passed:
April 25, 2025

Frequently Asked Questions

Why a mini-split instead of central AC for a condo?
Condos typically don’t have existing ductwork for central forced-air systems. Installing ductwork in a 2008 conversion with concrete deck floors and historic brick walls would be invasive and expensive. Mini-splits use refrigerant lines instead of ducts, requiring only a small wall penetration. For Naomi’s open-plan layout, a single mini-split head provides effective cooling and heating distribution.
Why cold-climate H2i Hyper-Heat instead of standard mini-split?
Three reasons. (1) Salt Lake’s 9°F design temperature requires cold-climate rating for effective heating. Standard mini-splits lose significant capacity below 30°F. (2) NEEP CCASHP listing makes the equipment eligible for full federal IRA 25C heat pump tax credit (up to $2,000); standard mini-splits may not always qualify. (3) HSPF2 11.0 means approximately 3x more efficient than electric baseboard heat — significant operating cost reduction for primary heating use.
How did you handle the HOA approval process?
4 weeks. Process: prepared exterior modification request with condenser placement plan, refrigerant line routing diagram, masonry penetration plan, and HOA-approved contractor names. HOA imposed conditions (paint matching, decorative grate, lime-based mortar) were all reasonable and incorporated into the installation plan. We coordinated with HOA-approved masonry contractor; he billed customer directly for masonry work. Allow 4-8 weeks for HOA approval in historic conversion buildings.
Why was a masonry contractor needed?
Original 1907 multi-wythe brick exterior wall (approximately 12″ thick) required core drilling for refrigerant line set penetration. HOA required lime-based mortar (rather than modern Portland cement) for patching, per historic preservation guidelines. HOA-approved masonry contractor handled both the core drilling and post-installation patching. We coordinated scheduling but didn’t perform the masonry work.
Are the baseboard heaters now obsolete?
No, they’re useful backup. Heat pump handles all Salt Lake winter conditions to 5°F outdoor at full capacity, continued operation to -15°F. For very cold nights (sub-15°F), the baseboard heaters provide supplemental capacity. Naomi keeps them on backup setting (50°F floor) so they only activate if heat pump can’t maintain temperature. Estimated 5-8 nights per winter trigger baseboard activation. Long term, baseboards could be removed if Naomi wanted, but they’re not actively costing anything if not running.

Project Details Summary

Customer:
Naomi B. (consent for documentation given)
Property:
Downtown Salt Lake City 1907 brick warehouse condo conversion (2008), 1,180 sq ft
Project:
Single-zone ductless mini-split installation (cooling + primary heating with electric baseboard backup)
Completion date:
April 22, 2025
Total cost:
$7,800 installed, $7,400 net after Wattsmart rebate, $6,200 effective after federal tax credit (plus $785 separate masonry contractor)
Equipment installed:
Mitsubishi MUZ-FS18NAH outdoor condenser (cold-climate H2i Hyper-Heat 20.2 SEER2 / 11.0 HSPF2), Mitsubishi MSZ-FS18NA indoor wall-mounted head, kumo cloud Wi-Fi adapter
Outcome:
Whole-condo cooling with 19 dB low-speed operation vs. previous portable AC compromise. Winter heating bill reduction approximately $185/month vs. baseboard-only operation. Approximate 4-5 year payback period on energy savings.
Ongoing service relationship:
Premium Care plan member since April 2025. Annual tune-up scheduled April 2026.

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