Case Study: Zoned System Upgrade in Brentwood Creek, La Vista
This case study documents a zone control retrofit for a 2008 two-story home in the Brentwood Creek subdivision of La Vista. The customer experienced substantial floor-to-floor temperature differential despite a relatively new home with functional matched system equipment. Two-zone retrofit with smart thermostats and motorized dampers produced substantial comfort improvement at modest cost, without replacing the functional existing HVAC equipment.
Customer Situation
The property is a 2008 two-story home in Brentwood Creek subdivision, 2,200 sq ft on a 7,500 sq ft lot. The customers (couple in their late 30s with two children ages 5 and 8) had purchased the home 5 years ago and grown frustrated with persistent comfort issues across both heating and cooling seasons.
Existing equipment:
- 2020 Lennox EL296V two-stage 96% AFUE furnace (5 years old, operating well after recent replacement following 2008 original equipment failure)
- 2020 Lennox EL18XCV two-stage 18 SEER2 AC (5 years old, operating well)
- Single first-floor thermostat (basic programmable)
- Builder-installed ductwork from 2008 original construction
Symptoms prompting service:
- Summer: first floor comfortable at thermostat setpoint, second floor 5-7°F warmer (bedrooms hot at bedtime)
- Winter: opposite pattern, second floor warm and first floor cool during morning hours
- Children’s bedroom comfort particularly affected during summer cooling
- Master bedroom suite (second floor) also affected by overshooting in summer
- Customer interested in smart thermostat capability and smartphone control
Diagnostic Assessment
Consultation by Jess Sandoval (Install Lead, 11 years, Manual D specialty). Assessment time approximately 1.5 hours including thermal evaluation and ductwork inspection.
Property and Equipment Assessment
- 2008 builder construction with adequate insulation but typical builder-grade ductwork
- Existing equipment performing well; recent 2020 replacement provides 15+ years remaining lifespan
- 200-amp electrical service adequate for zone control addition
- Single supply trunk feeding both floors through branch ductwork
Thermal Differential Analysis
- First floor: living room, kitchen, dining, home office, master bath, garage entry
- Second floor: master bedroom suite, two children’s bedrooms, secondary bath, laundry
- Convection patterns: heated air rises producing second-floor warming during heating; cooled air settles producing first-floor accumulation during cooling
- Standard builder single-thermostat configuration inadequate for two-story residence with substantial occupancy across both floors
Zone Control Options
- Option A — Standard two-zone retrofit — first floor as Zone 1, second floor as Zone 2; motorized dampers in supply ductwork; two smart thermostats. $3,985 total.
- Option B — Smart thermostat only (no zone control) — replace thermostat with single smart thermostat. $385 total. Addresses scheduling and smartphone control but not temperature differential issue.
- Option C — Mini-split addition for second floor — supplemental ductless mini-split for second floor only. $8,500-$10,500 total. Substantial cost but complete independent control.
Customer selected Option A based on cost-benefit analysis: addresses the actual differential issue at moderate cost, smart thermostat capability included.
Equipment Selection
- Honeywell TrueZONE HZ322 two-zone control panel — compatible with Lennox two-stage equipment
- Two motorized dampers — first-floor supply branch and second-floor supply branch
- Two ecobee Smart Thermostat Premium units — with room sensors for additional monitoring
- Bypass damper — for static pressure management during single-zone operation
Project Execution
Standard two-day zone retrofit project:
Day 1 (5 hours) — Ductwork modification: motorized damper installation in first-floor and second-floor supply branches, bypass damper installation for static pressure management, return air verification.
Day 2 (4 hours) — Zone control panel installation in mechanical room, wiring between control panel and furnace/AC, ecobee thermostat installation (two units), commissioning of two-zone operation, customer walkthrough including smartphone app setup and operation explanation.
Results
- Temperature differential resolved — first/second floor differential reduced from 5-7°F to 1-2°F across heating and cooling seasons
- Children’s bedroom comfort improved — second-floor cooling now maintains appropriate temperatures during summer
- Master bedroom comfort improved — no longer overshooting during summer cooling
- Smart thermostat capability — smartphone control, scheduling, geofencing, room sensor monitoring
- Energy efficiency improvement — estimated 10-15% reduction in heating/cooling energy through zone-specific operation
- Equipment cycling optimization — two-stage equipment operates particularly well with zone control; reduced first-stage capacity matches single-zone load
- Customer satisfaction — substantial improvement in family comfort, particularly during summer cooling
Customer Use Patterns Post-Installation
- Different zone setpoints during different times of day matching family use patterns
- Children’s zone (second floor) cooler during summer evenings before bedtime
- First-floor setback during overnight when family is in second-floor bedrooms
- Geofencing automatically adjusts setpoints when family leaves/returns
- Smartphone monitoring identifies any developing comfort issues
- Room sensor in master bedroom provides additional temperature monitoring
Pricing
Total project cost: $3,985
- Honeywell TrueZONE HZ322 two-zone control panel: $385
- Two motorized dampers: $485 ($245 each)
- Two ecobee Smart Thermostat Premium units (with room sensors): $885
- Bypass damper installation: $285
- Ductwork modifications: $385
- Installation labor (9 hours over 2 days): $1,185
- Wiring, materials, miscellaneous: $185
- Smart thermostat smartphone app setup and customer training: $190
No federal tax credits or OPPD rebates apply to zone control retrofit; the work doesn’t qualify under current incentive programs which focus on equipment efficiency.
Two-Stage Equipment + Zone Control Performance
The combination of existing two-stage equipment with new zone control produces particularly good results:
- Two-stage equipment first-stage capacity (~65% of rated) matches single-zone load appropriately
- When one zone is calling, equipment operates at first-stage for extended steady-state cycles
- When both zones are calling simultaneously (rare during typical conditions), equipment switches to second-stage handling full load
- Bypass damper ensures proper static pressure regardless of which zones are open
- This combination produces approximately 10-15% energy reduction vs single-thermostat operation of same equipment
Lessons from This Project
- Two-story builder-grade homes frequently benefit from zone control retrofit; standard single-thermostat configuration inadequate for two-story occupancy
- Recent equipment replacement makes zone retrofit particularly cost-effective; no equipment replacement cost interferes with zone control investment
- Two-stage equipment combined with zone control produces superior results to single-stage equipment with zone control
- Smart thermostats add substantial capability (smartphone control, scheduling, geofencing) beyond basic programmable
- Bypass dampers are essential for proper static pressure management in residential zone control systems
- Room sensors provide additional monitoring beyond the thermostat location, identifying comfort issues in specific spaces
Contact Omaha Heating and Air Conditioning
For La Vista Brentwood Creek zone control retrofit, smart thermostat installation, two-story comfort improvement, or builder-grade home upgrade consultation, call our 24/7 line.
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- Email: info@omahaheatingairconditioning.xyz
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