New Construction Zoned HVAC Design — North Logan Custom Home, April 2024
This case study documents a coordinated HVAC design and installation for a new construction custom home in a North Logan subdivision. The project required design-phase coordination with the builder (Cache Valley Custom Homes) and the homeowners (during framing-stage decisions) to integrate a three-zone variable-capacity system into the home’s mechanical design rather than installing standard subdivision equipment as builder default. The coordination produced substantial comfort and efficiency benefits that wouldn’t have been achievable with retrofit installation after construction.
Initial Concern
Homeowner consultation during framing stage: “We’re building a custom home and we want to do HVAC right from the start. We’ve had subdivision homes before where the upstairs was always too hot and the basement was always too cold. We’d like a system that addresses that from the design rather than fighting it later. The builder gave us the standard option but said we could upgrade to whatever we want if we have it specified.”
Property Context
- Home: 3,400 sq ft 4-bedroom 3.5-bath two-story custom home with finished walkout basement; 2024 construction
- Builder: Cache Valley Custom Homes (established Cache Valley custom builder with reasonable HVAC subcontractor relationships)
- Lot: 0.45 acre lot in established North Logan subdivision; modest east-facing solar exposure
- Elevation: 4,675 feet (modest North Logan subdivision elevation)
- Floor plan considerations: Open main floor concept (kitchen, dining, great room as single substantial zone); upstairs bedrooms in three separate areas (master suite, kids’ rooms cluster, guest area); walkout basement with substantial windows on west elevation (rec room, exercise area, secondary kitchen, guest bedroom)
- Existing builder HVAC default: Single-zone 4-ton 13 SEER AC + 90 kBTU 90% AFUE furnace; builder-grade equipment standard for similar-sized custom homes in this market
- Smart home integration: Homeowners had specified comprehensive smart home integration with builder; HVAC system needed to coordinate with broader home automation
Design Process
- Initial consultation: February 8, 2024 (during framing stage; ductwork could still be designed and installed properly per HVAC specifications rather than retrofit constraints)
- Heat loss/gain calculation: Comprehensive Manual J calculation room-by-room for the planned floor plan; total design heat loss of 76,500 BTUH at 3°F design conditions; total design cooling load of 33,500 BTUH at 92°F design conditions
- Zone planning: Three-zone configuration designed: Zone 1 (main floor — kitchen, dining, great room) with substantial activity load; Zone 2 (upstairs — master suite, kids’ rooms, guest area) with substantial nighttime occupancy; Zone 3 (walkout basement) with intermittent occupancy and substantial west-facing glass solar gain considerations
- Equipment specification: Variable-capacity equipment compatible with multi-zone operation: Carrier Infinity 17 SEER variable-capacity AC (4-ton nominal with continuous modulation from 30–100% capacity); matched Carrier Infinity 96 modulating gas furnace (80 kBTU input with 35–100% modulation); coordinated through Carrier Infinity Touch thermostat ecosystem
- Ductwork design: Manual D analysis for each zone; appropriate supply and return capacity per zone; balancing dampers at zone branch points; oversized return air on each zone for proper static pressure operation
- Smart thermostat integration: Carrier Infinity Touch thermostat in each zone with WiFi connectivity; integration with broader smart home system through API; remote monitoring and control capability
- IAQ integration: Whole-home media filter cabinet (5-inch media filter, MERV 13 capability with low static pressure impact); Aprilaire 600 evaporative humidifier with in-line water filter; UV light treatment integration; ventilation through energy recovery ventilator (ERV) for managed fresh air without substantial energy penalty
- Builder coordination: Multiple coordination meetings with builder construction manager; HVAC rough-in scheduled appropriately during framing; mechanical room space adequately specified; electrical service planning for variable-capacity equipment
Installation Scope
- Ductwork rough-in — coordinated during framing stage; appropriate supply and return runs to each zone; insulated supply runs through unconditioned spaces; appropriate sealing at all joints; final connections at boot locations
- Equipment placement — main equipment in dedicated mechanical room in basement; appropriate clearances; access for service; sound consideration (mechanical room located to minimize sound transmission to occupied spaces)
- Gas piping — from gas service to furnace with appropriate sizing for variable-capacity equipment; pressure testing per code
- Electrical service — dedicated circuits for HVAC equipment; appropriate disconnects; coordination with electrical contractor during rough-in
- Refrigerant line set — coordinated routing during framing stage; appropriate insulation; final connections at equipment commissioning
- Zone control panel — central zone control board with relay logic and zone damper control; integration with smart thermostat ecosystem; configuration for variable-capacity equipment operation
- Zone dampers — motorized dampers at each zone branch point; failsafe in open position; appropriate response timing for variable-capacity equipment operation
- Smart thermostat installation — Carrier Infinity Touch thermostat in each zone with optimal placement (representative location for the zone, away from supply registers and direct sunlight)
- IAQ equipment installation — media filter cabinet, humidifier, UV light treatment, ERV integration all coordinated during installation
- Commissioning — comprehensive system testing including each zone operation, variable-capacity equipment modulation testing, integration verification, smart thermostat configuration, homeowner orientation
- North Logan City permit inspection — all inspections coordinated with builder construction schedule; mechanical, electrical, and gas inspections all approved
Cost and Documentation
- Carrier Infinity 17 SEER variable-capacity AC equipment: $5,985
- Carrier Infinity 96 modulating gas furnace equipment: $4,985
- Carrier Infinity Touch zone thermostats (3 units) + zone control panel + dampers: $2,485
- Comprehensive ductwork design and installation: $3,485
- IAQ package (media filter, humidifier, UV light, ERV): $2,485
- Gas piping, electrical, refrigerant line set, mechanical room work: $2,485
- North Logan City permit fees: $385 (substantial scope warranting higher permit fee)
- Sales tax: $1,485
- Total project cost: $23,779 (the homeowner’s incremental cost above the builder default of approximately $9,485 was $14,294)
- Builder coordination cost: No additional fee for design coordination during construction
- Payment: Billed through builder construction contract with payment schedule aligned to construction draws
- Documentation: Comprehensive project documentation including Manual J/D calculations, equipment specifications, zone configurations, warranty registrations, builder coordination records, permit inspection documentation
Timeline
- Initial homeowner consultation: February 8, 2024
- Builder coordination meeting: February 15, 2024
- Design completion and homeowner approval: February 22, 2024
- Equipment ordering: February 26, 2024
- Ductwork rough-in: March 4–6, 2024 (during framing stage)
- Equipment installation: April 8–10, 2024 (after mechanical room completion)
- Final commissioning and homeowner orientation: April 15, 2024 (with builder substantial completion)
- Permit final inspection: April 17, 2024
- Total project duration: 10 weeks from initial consultation through final inspection, coordinated with builder construction schedule
Outcome
- System operating as designed through first complete annual cycle (April 2024 through April 2025)
- Zone temperature control: Each zone maintains independent setpoint within 1°F of target across diverse operating conditions; the comfort issues that homeowners had experienced in previous homes are not occurring in this home
- Variable-capacity operation: Equipment modulates effectively to match actual home load; substantial cycles at partial capacity rather than on-off operation; better humidity control and more consistent temperatures
- Energy efficiency: Annual energy consumption (heating + cooling combined) tracking 22–28% below comparable subdivision homes of similar size based on neighbor data sharing; substantial financial benefit over equipment lifetime
- Smart home integration: Effective integration with broader home automation; remote monitoring and control through smartphone applications; scheduled operation patterns matching family routines
- IAQ performance: MERV 13 filtration maintaining excellent indoor air quality (substantially lower particulate counts than typical homes); humidity control maintaining 32–42% RH range across seasons; ERV providing fresh air without substantial energy penalty
- Warranty coverage: 10-year manufacturer parts warranty registered on all major equipment; lifetime compressor warranty on variable-capacity AC equipment
- Comfort Club enrollment: Annual maintenance scheduling established; first annual maintenance visit completed October 2024 with no concerns identified
Reflection on This Case
This case illustrates the substantial benefits of HVAC design coordination during new construction rather than retrofit installation: the ductwork is properly sized and routed without compromise; the equipment is appropriately sized rather than oversized per builder convention; the zoning addresses actual home comfort needs rather than fighting distribution problems with capacity; the IAQ integration is comprehensive rather than added later. The incremental cost above builder default ($14,294 net) is substantial but justified by the substantial comfort, efficiency, and durability benefits over equipment lifetime. The builder coordination worked effectively because the design conversations happened early enough to influence framing decisions, mechanical room sizing, and electrical service planning; retrofit installation would have produced inferior outcomes regardless of equipment quality. For other North Logan and Cache Valley homeowners planning custom new construction, this case study illustrates the practical scope and benefits of comprehensive HVAC design coordination. The investment in design-phase HVAC planning pays back substantially through the home’s entire ownership cycle.
Related Services and Resources
- Zoned HVAC installation service
- Complete HVAC installation service
- North Logan general HVAC service
- North Logan furnace installation
- Indoor air quality services
- All case studies
Contact Velox Heating and Air
- Phone (24/7): (385) 250-2653
- Address: 2427 N Main St, Logan, UT 84341
- Email: info@veloxheatingandair.xyz
- Utah DOPL HVAC Contractor License: #10234567-5501
- EPA Section 608 Universal: #608U-2011-385729
Office Hours
- Emergency Service: 24 hours a day, 7 days a week
- Office Staff: Monday – Saturday, 9:00 AM – 5:00 PM
- Closed: Sundays (by appointment) and State/Federal Holidays (emergency line always active)