New Build Air Handler Commissioning — Nibley Subdivision Custom Home, March 2024

This case study documents comprehensive HVAC commissioning at a newly-constructed Nibley subdivision custom home. The project differs from typical builder-default HVAC installations: comprehensive Manual J verification at design completion, thorough equipment commissioning including measurement-based verification rather than installation-checklist completion, and substantial homeowner orientation upon home delivery. The project illustrates the practical value of comprehensive commissioning for new construction HVAC.

Initial Concern

Homeowners (during pre-purchase consultation): “We’re buying a new home in the Nibley subdivision that’s being built by Cache Valley Custom Homes. The builder uses your company for HVAC and we’d like to make sure the system is installed and commissioned properly before we close. We’ve heard stories about new home HVAC having ongoing comfort issues from inadequate commissioning. Can we engage with you directly for an additional commissioning pass beyond the builder’s standard installation?”

Property Context

• Home: 2,600 sq ft 4-bedroom 3-bath two-story subdivision home, 2024 construction; Nibley new subdivision development
• Builder: Cache Valley Custom Homes (the same builder coordinated with on previous case studies); reasonable HVAC subcontractor relationships
• Equipment specified by builder: Carrier 90% AFUE 80 kBTU two-stage gas furnace; matched Carrier 16 SEER 3-ton AC; standard new construction equipment for this subdivision price point
• Existing HVAC scope: Builder default scope (equipment, ductwork, thermostat) per Cache Valley Custom Homes standard new construction package
• Construction timeline: Home under construction since late 2023; HVAC rough-in completed during framing; equipment installation scheduled for finish phase; substantial completion expected March 2024
• Buyer engagement timing: Buyers approached us 6 weeks before substantial completion to discuss enhanced commissioning beyond builder default; allowed substantial coordination time

Design Verification

• Manual J review: Reviewed builder’s sizing assumptions; performed independent Manual J calculation; verified design heat loss of 56,500 BTUH at 3°F (the 80 kBTU furnace at 90% AFUE provides 72 kBTU output, appropriate sizing with reasonable margin); design cooling load of 26,500 BTUH (the 3-ton AC provides 36 kBTU nominal, appropriate sizing for the home with the substantial west-facing afternoon solar exposure)
• Manual D review: Reviewed builder’s ductwork sizing; verified appropriate sizing for each branch; identified one minor concern (master bedroom branch slightly undersized for the room’s heat loss) that warranted modification before installation completion
• Equipment placement verification: Mechanical room location reviewed for service access; appropriate clearances confirmed; outdoor condenser location verified for noise and aesthetic considerations
• Builder coordination: Single coordination call with builder construction manager confirmed acceptance of master bedroom branch sizing modification; minor change accommodated within construction schedule

Commissioning Process

• Pre-installation verification: Equipment receipt verified against specifications; equipment in factory-sealed condition without damage; documentation packages reviewed
• Installation oversight (collaborative with builder’s installation crew): Equipment placement verified; gas piping connections verified appropriate; electrical service connections verified; venting installation per code; condensate drainage routing verified appropriate
• Static pressure verification: External static pressure measured at 0.42 in. wc (well within 0.5 in. wc maximum specification); no operational concerns
• Combustion analysis: Bacharach Insight Plus combustion analyzer connected; verified 28 ppm flue gas CO (well below 100 ppm threshold), zero indoor space CO (sealed combustion equipment verified), 7.8% O2, 8.2% CO2, 92.4% combustion efficiency (consistent with 91% AFUE nameplate rating)
• Refrigerant charge verification: Pressure testing per EPA standards; refrigerant charge to manufacturer specifications based on line set length; superheat and subcooling verification within proper range
• Two-stage operation verification: Both high-stage and low-stage operation verified for cooling and heating; appropriate response to thermostat call levels; equipment modulation working as designed
• Airflow measurement at each register: Supply air measured at every register throughout home; compared against Manual D calculations; verified appropriate distribution within tolerance (within 10% of target for all registers)
• Return air measurement: Return air verified adequate for equipment capacity; no return air restriction issues
• Thermostat operation: Carrier Comfort Series basic thermostat operation verified; programming explained for homeowner reference; sensor location appropriate
• Safety verification: Limit switch operation, pressure switch operation, flame sensor operation, igniter operation, all verified through controlled testing

Homeowner Orientation

• Comprehensive orientation visit: 90-minute visit with homeowners on move-in day; comprehensive equipment walkthrough
• Filter change demonstration: Demonstrated filter location, removal, installation; explained 3-month change interval for 1” pleated filter with new construction debris consideration; mentioned upgrade path to 5” media filter cabinet if desired in future
• Thermostat operation: Demonstrated thermostat operation including programming; explained two-stage operation indication; explained system mode selection (heating, cooling, auto, off)
• Annual maintenance importance: Discussed value of annual maintenance for new equipment (warranty preservation, performance monitoring, preventive identification of developing concerns); Comfort Club enrollment offered
• Warranty documentation: Manufacturer warranty registration completed (10-year parts warranty registered to homeowners); Velox installation warranty explained (2-year labor warranty for new construction installation)
• Documentation provided: Service manual, warranty documentation, commissioning report, recommended maintenance schedule
• Cache Valley considerations: Discussed Cache Valley climate factors (inversions, dry winters, hard water humidifier considerations for future) relevant to home operation
• Questions and follow-up: Substantial time for homeowner questions; follow-up contact information provided for non-emergency questions during settling-in period

Cost and Documentation

• Independent Manual J verification: $285 (substantial design review work beyond builder default)
• Commissioning verification scope: $585 (substantial measurement-based verification beyond installation checklist)
• Homeowner orientation visit: $185 (90-minute comprehensive walkthrough)
• Master bedroom branch modification (coordinated with builder): Included in builder construction cost (no separate Velox charge)
• Total enhanced commissioning cost: $1,055 (incremental cost above standard builder HVAC scope)
• Payment: Homeowner direct payment to Velox after substantial completion
• Documentation: Comprehensive commissioning report including Manual J results, measurement verification, equipment specifications, warranty registrations, recommended maintenance schedule

Outcome

• Equipment operation verified excellent — comprehensive commissioning verified appropriate operation across all measured parameters; no operational concerns identified at startup
• Comfort consistently appropriate — homeowners report uniform comfort across home from move-in through 14+ months of operation; the substantial commissioning effort eliminated the typical “new home settling” comfort issues
• Energy efficiency tracking favorable — first-year energy consumption tracking 8–12% below similar subdivision homes based on neighborhood data sharing (the master bedroom branch modification and appropriate sizing produces measurable benefits)
• Two-stage operation effective — low-stage operation handles typical Cache Valley winter conditions effectively (approximately 65% of heating hours at low stage); high-stage appropriately reserved for severe cold
• Homeowner satisfaction — substantial positive feedback; the comprehensive commissioning and orientation provided substantial value vs. typical new home turnover experiences
• Comfort Club enrollment at move-in; first annual maintenance completed November 2024 (no concerns identified); ongoing service relationship established
• Warranty preservation: Manufacturer warranty fully registered and documented; comprehensive commissioning protects warranty validity (manufacturer warranties typically require demonstrated proper installation; thorough commissioning provides documentation)
• Reference for builder coordination: Builder reported substantial value from the enhanced commissioning collaboration; subsequent builder projects increasingly include similar enhanced commissioning

Reflection on This Case

This case illustrates the substantial value of enhanced HVAC commissioning beyond builder default scope: independent Manual J verification catches sizing issues before they produce comfort problems; measurement-based commissioning verifies actual equipment performance rather than installation checklist completion; comprehensive homeowner orientation enables appropriate equipment operation from move-in; ongoing maintenance relationship preserves equipment performance and warranty coverage. The modest incremental cost ($1,055 above builder default) produces substantial benefits throughout equipment service life; the comfort improvements alone justify the investment, before considering energy efficiency benefits and warranty preservation. The honest framing for new construction home buyers: builder HVAC scope is typically adequate but commissioning quality varies substantially; engaging independently with the HVAC contractor for enhanced commissioning often produces substantially better outcomes than relying on builder default; the small incremental cost is well-spent for buyers who value comfort, efficiency, and warranty protection. The Cache Valley Custom Homes builder coordination worked well because the collaboration was established early enough to influence ductwork sizing decisions during framing; later engagement would have limited the scope of meaningful improvement. For Cache Valley homebuyers considering similar enhanced commissioning, we recommend engaging during framing stage rather than after substantial completion. The Nibley subdivision context (modest subdivision homes vs. substantial custom homes) doesn’t change the fundamental value of comprehensive commissioning; the same principles apply at all price points though the absolute dollar impact varies with home size and equipment scope.

Related Services and Resources

• Complete HVAC service
• Air handler services
• HVAC tune-up service
• Nibley general HVAC service
• Comfort Club maintenance plans
• All case studies

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