Webster Park Mixed-System: 1932 Tudor Combined Hydronic Heating and Ducted Cooling

Case study summary: 1932 Tudor Revival home in Webster Groves’ Webster Park neighborhood with hydronic heating to cast-iron radiators throughout home; customer wanted to add central AC primarily for second-floor cooling without compromising existing hydronic distribution; installed Carrier 24ANB7 2-ton AC with new ductwork system focused on second-floor cooling via attic-mounted air handler and ceiling registers; preserved hydronic heating distribution; total project cost $18,400; completed in 4 days during April-May 2026 with Webster Groves HPC review. Outcome: dramatically improved second-floor cooling (previously 78-82°F upstairs vs. 73°F downstairs during summer); preserved hot water radiator heating; modest first-floor cooling benefit through attic-zone register placement; customer satisfaction high with mixed-system approach.

The Home

• Built: 1932
• Style: Tudor Revival
• Location: Webster Park neighborhood, Webster Groves, MO 63119
• Size: 1,420 sf main level plus 1,140 sf second floor plus unfinished attic (2,560 sf conditioned)
• Construction: Wood frame with brick veneer first floor, stucco and half-timber second floor; plaster walls throughout interior; original wood floors; leaded glass windows in front rooms
• Existing heating: Burnham Series 2 cast-iron boiler (2017, 88% AFUE, 8 years old) serving cast-iron baseboard radiators throughout home; system in good condition with no changes during this project
• Existing cooling: window AC units removed for new system (1 unit in each second-floor bedroom)
• Available attic space: 1,000 sf unfinished attic with adequate height (5′-6′ to ridge) and access for air handler installation
• Historic preservation status: Webster Park historic overlay requires HPC review for exterior modifications

The Situation

Customer contacted us in February 2026 about second-floor cooling primarily. Drivers:

• Upstairs cooling inadequacy: window AC units in second-floor bedrooms provided some relief but were inadequate during peak summer heat; second-floor bedrooms regularly reached 78-82°F during summer evenings even with window units running
• Hydronic heating preservation: customer’s 2017 boiler was 8 years old, in excellent condition with 12-17 years remaining service life; customer wanted to preserve hydronic heating that provided excellent comfort character
• Family member with health considerations: customer’s elderly mother spends extended periods in upstairs guest bedroom; consistent cooling during summer became health priority
• Window AC aesthetic concerns: Webster Park historic district concerns about window AC visibility; HPC compliance for exterior modifications including window AC removal preferred

Initial assessment evaluated three approaches:

• Whole-home ducted AC with attic air handler: standard approach providing cooling to entire home through new ductwork installed in attic and through ceiling penetrations to first and second floors
• Ductless mini-split for second floor only: targeted approach providing cooling specifically to second-floor bedrooms via wall-mounted indoor units
• Ducted second-floor-focused system with limited first-floor benefit: hybrid approach providing primary cooling to second floor through attic ductwork with one first-floor register tap for some benefit on main floor

Customer selected the third option after evaluating cost, complexity, and comfort outcomes for each.

The Equipment Selection

Carrier 24ANB7 2-Ton AC (Selected)

• SEER2: 16.0
• Capacity: 2 tons (24,000 BTU/hr); appropriate for second-floor-focused cooling load plus modest first-floor benefit
• Refrigerant: R-454B
• Technology: Single-stage scroll compressor; appropriate for relatively small home not needing variable-capacity
• Why selected: appropriate capacity for second-floor-focused cooling without oversizing; single-stage equipment lower cost than variable-capacity matching customer’s modest expectations for first-floor benefit; Carrier brand strong dealer support

Carrier FH4ANF Variable-Speed Horizontal Air Handler

• Type: Horizontal-flow air handler with ECM variable-speed blower; designed for attic installation
• Capacity: matches 2-ton condenser
• Location: attic-mounted on platform with appropriate insulation and sound damping

Honeywell T6 Pro Programmable Thermostat

• Single thermostat for new ducted system; located in second-floor hallway (representative of cooling demand priority)
• Separate from existing thermostat controlling hydronic boiler (no integration between heating and cooling controls in this mixed-system approach)

Alternative Equipment Considered

• Mitsubishi 3-zone ductless: alternative for second-floor focus; would have provided indoor units in 3 second-floor bedrooms; cost approximately $13,800 for similar coverage; selected against because customer wanted central ducted approach
• Whole-home ducted AC with 3-ton capacity: full home cooling approach; cost approximately $22,800 for similar quality equipment with whole-home ductwork; customer chose second-floor-focused approach as adequate for primary need at lower cost
• Heat pump alternative for combined cooling/supplemental heating: would have provided some heating benefit during shoulder seasons; cost premium $2,800-$3,600; customer’s existing 2017 boiler provided adequate heating without need for supplemental capability

The Project Scope

Pre-Installation Coordination

• Webster Groves HPC review: Submitted for outdoor unit placement on side-yard concrete pad behind existing fence (non-visible from street); approval received in 19 days
• Webster Groves Public Works permit: Pulled within 5 business days of HPC approval
• Equipment ordering: 8 business days for Carrier equipment

Installation Day 1 (April 28, 2026)

• Outdoor unit placement on concrete pad in side yard behind existing fence
• Electrical service: dedicated 240V circuit installed from main panel
• Refrigerant line set routing from outdoor unit through exterior wall to attic location
• End of Day 1: outdoor unit placed, exterior routing complete

Installation Day 2 (April 29, 2026)

• Attic preparation: platform installation for air handler placement; access pathways verified
• Carrier FH4ANF horizontal air handler placement in attic
• Initial ductwork installation: insulated flexible ducts routed in attic to ceiling register locations on second floor
• End of Day 2: equipment installed, ductwork partially complete

Installation Day 3 (April 30, 2026)

• Ceiling register installations on second floor (4 supply registers: each of 3 bedrooms plus hallway)
• First-floor benefit register: single supply tap routed through ceiling at master bedroom location with ceiling register also serving the room below (providing some first-floor benefit; full first-floor cooling would have required substantial additional ceiling work)
• Return air opening cut into second-floor hallway ceiling with grille at hallway location
• Condensate management from attic-mounted air handler: condensate pump pumping condensate to nearest plumbing drain (master bathroom drain)
• End of Day 3: equipment substantially installed

Installation Day 4 (May 1, 2026)

• Refrigerant system commissioning: nitrogen pressure test, vacuum pull, refrigerant charge
• Subcooling and superheat verification
• Honeywell T6 Pro thermostat installation in second-floor hallway location
• Cooling performance verification at all registers
• Customer walk-through: explained operation, expected first-floor vs. second-floor comfort differences, maintenance schedule
• Final cleanup and customer sign-off

Inspection (May 8, 2026)

• Webster Groves Public Works inspector visit; installation passed inspection

The Pricing

• Carrier 24ANB7 2-ton condenser: $3,200 equipment
• Carrier FH4ANF horizontal variable-speed air handler: $2,800 equipment
• Honeywell T6 Pro programmable thermostat: $180
• Installation labor (4 days, 2 technicians): $5,200
• Attic ductwork (insulated flexible ducts, fittings): $1,400
• Air handler attic platform installation: $580
• 5 ceiling registers (4 second-floor plus 1 first-floor benefit tap): $380
• Ceiling penetration drywall work and patches: $480
• Return air grille and ductwork: $280
• Refrigerant line set installation: $480
• Dedicated 240V electrical circuit: $580
• Condensate pump and routing to bathroom drain: $240
• Sealed combustion exterior wall penetration for refrigerant line set: $180
• Webster Groves Public Works permit: $280
• Webster Groves HPC review fee: $180
• Refrigerant charge and commissioning materials: $300
• Exterior siding repair at penetration: $240
• Bacharach combustion analysis and commissioning: $200
• Drywall patching at thermostat and register locations: $180
• Miscellaneous fittings, hardware, mastic, and consumables: $200
• Total project cost: $17,580 rounded to $18,400 with permit contingency and material variances during 4-day installation

This pricing fell within our standard range for second-floor-focused central AC installations in pre-1950 homes with existing hydronic heating preserved ($15,000–$22,000 depending on attic access, ductwork complexity, and historic preservation requirements).

The Outcome

Cooling Performance

• Second-floor cooling: dramatic improvement from previous window AC inadequacy; bedrooms maintain 73-75°F setpoint reliably even during peak summer heat
• First-floor benefit: master bedroom register on first floor provides some cooling benefit during AC operation; first-floor temperature approximately 4-6°F below outdoor temperature during AC operation, less than dedicated whole-home system would provide but adequate per customer’s expectation
• Sustained capacity: 2-ton equipment adequately handles second-floor cooling load with appropriate margin; doesn’t struggle during peak demand

Hydronic Heating Preservation

• Existing 2017 boiler operation unchanged: continues to serve cast-iron radiators throughout home
• Heating distribution unaffected: hydronic baseboard heating provides same comfort character as before AC installation
• No equipment conflict: cooling and heating systems operate independently with separate thermostats controlling each

Customer Feedback

Customer reported high satisfaction with several aspects: second-floor bedroom cooling for elderly mother resolved primary comfort priority; window AC units removed providing better home appearance and HPC compliance; existing hydronic heating preserved; mixed-system approach cost less than whole-home ducted alternative while providing primary needed benefit; understanding of first-floor vs. second-floor cooling difference set realistic expectations.

Ongoing Service

Customer enrolled in maintenance plan covering both hydronic boiler and new ducted cooling system; service visits scheduled spring (cooling system) and fall (boiler).

Frequently Asked Questions

Why not install whole-home central AC since you’re adding ducts?

Cost vs. benefit analysis drove the second-floor-focused decision. Whole-home ducted AC requirements: substantially more ductwork in attic and through ceilings to all rooms (5-7 supply registers on first floor plus 4 on second floor); additional return air paths; larger air handler capacity (3-ton vs. 2-ton); more substantial supply trunk runs through floor framing or ceiling soffits. Cost comparison: second-floor-focused approach $18,400 (this case study); whole-home ducted approach estimated $22,800 for similar quality equipment; net difference approximately $4,400. Benefit comparison: second-floor focus addresses customer’s primary cooling priority (upstairs bedrooms for elderly mother); whole-home approach would provide more uniform whole-home cooling; first-floor in this home stays relatively cool due to brick veneer construction, large shade trees, and tile floors. Customer decision factors: primary cooling priority was upstairs bedrooms which the second-floor-focused approach fully addresses; first floor was adequately comfortable during summer with windows open and ceiling fans; the $4,400 cost premium for whole-home cooling didn’t justify the modest additional benefit; HPC compliance is simpler with smaller equipment footprint. For other customers considering similar decisions: depends on actual comfort needs across home; customers with consistent whole-home comfort priorities should consider whole-home approach; customers with focused cooling priorities can benefit from targeted approach at lower cost. We discuss both options during quote development including realistic expectation-setting about what each approach provides.

What’s special about attic-mounted air handlers?

Attic air handlers have specific advantages and considerations vs. basement or closet installations. Advantages of attic location: works for homes without basement equipment space; provides direct supply path to second-floor rooms via ceiling registers; doesn’t occupy living-space mechanical room; allows installation in homes (like this 1932 Tudor) where adding equipment elsewhere would require substantial home modifications. Considerations and trade-offs: temperature extremes in attic (140-150°F in summer, near outdoor temperatures in winter) affect equipment performance; insulation around equipment important to limit conditioned air loss through ductwork; condensate management more complex (condensate must be pumped or routed by gravity to acceptable drain location); access for maintenance more difficult than basement equipment; attic floor framing may need reinforcement for equipment weight; equipment service life slightly reduced due to temperature extremes. Mitigation strategies for this installation: substantial insulation around air handler (R-19 wrap on equipment plus floor insulation around platform); insulated flexible ductwork throughout (limits conditioned air loss); condensate pump routing to bathroom drain; floor framing assessment verified adequate for equipment weight; access through second-floor hallway ceiling access panel provides maintenance access. Performance impact: attic-mounted equipment in well-insulated attic space provides cooling efficiency within 95-97% of basement-mounted equivalent (small loss due to ambient temperature impact on equipment housing); reasonable trade-off for installation feasibility in homes without basement options. For other customers considering attic installations: typically appropriate when basement options aren’t available; insulation and condensate management scope critical for long-term performance; maintenance access planning should be addressed during installation.

How do you manage the seasonal transition between hydronic heating and ducted cooling?

Each system has its own thermostat operating independently; seasonal transition is manual setting changes on each thermostat. System independence: existing hydronic boiler thermostat in first-floor hallway (Honeywell T6 Pro programmable from 2017 boiler installation) controls heating; new ducted AC thermostat in second-floor hallway (Honeywell T6 Pro from this installation) controls cooling; thermostats have no communication between them. Seasonal operation patterns: heating season (October-April typically): boiler thermostat set to heating setpoint (typically 70°F); AC thermostat off or set to cool setting much higher than outdoor temperature (effectively off); cooling season (May-September typically): boiler thermostat off or set to heat setpoint below indoor temperature (effectively off); AC thermostat set to cooling setpoint (typically 73°F). Shoulder season operation (April-May, September-October): both systems may need to be inactive simultaneously; customer can use boiler thermostat at very low setpoint and AC thermostat at very high setpoint to allow indoor temperature to vary with outdoor conditions; this is acceptable when outdoor conditions provide comfortable indoor temperatures naturally. Why not integrated control: integrated control of separate heating and cooling systems requires communicating thermostat with both system protocols; this customer’s 2017 boiler doesn’t have modern smart communication protocols; integrating would require boiler control board replacement plus communicating thermostat; cost approximately $580-$880 additional which customer didn’t see justified for the modest convenience benefit. Customer-side operation: customer comfortable with separate thermostat operation; seasonal transition takes about 30 seconds of thermostat adjustment; less convenient than single-thermostat operation but acceptable for this customer’s preferences. For customers wanting integrated control: communicating thermostat options exist (Carrier Infinity, Trane ComfortLink, Bryant Evolution); requires compatible equipment on both heating and cooling sides; assessment during installation determines whether integration is feasible and cost-effective.

What’s the long-term plan if customer ever wants whole-home cooling?

Mixed-system installation provides flexibility for future expansion if needs change. Current state: second-floor cooling fully covered by ducted system; first floor receives modest benefit from single supply tap; first-floor comfort adequate due to home characteristics. Future expansion options if first-floor cooling becomes priority: additional first-floor ceiling registers tapped from existing supply trunk; ceiling work in first-floor public spaces would require some plaster modifications; estimated cost $4,400-$6,800 for 4-5 first-floor registers with appropriate finish work. Alternative future expansion: ductless mini-split additions for specific first-floor rooms with particular cooling needs; $2,800-$4,400 per single-zone ductless installation; targeted approach for specific rooms rather than whole-floor expansion. Equipment capacity considerations: existing 2-ton equipment is sized for current second-floor-focused scope; significant first-floor expansion would likely require equipment upsize to 3-ton; equipment replacement could be planned for natural end-of-service-life (15-20 years from now) when expansion would be appropriate timing. Cost staging benefits: customer’s mixed-system approach allows initial $18,400 investment for primary need; future expansion if/when desired at additional cost; total potential investment over years approaches whole-home ducted alternative but spreads cost across multiple years matching financial flexibility. For customers considering mixed-system approach: think about long-term comfort priorities and how needs may change; appropriate when current priorities are focused; whole-home approach upfront makes sense when customer is confident about long-term whole-home cooling needs. We discuss future expansion options during initial quote development so customers understand the path forward if needs change.

How does Webster Park’s HPC compare to Tuxedo Park and Old Webster?

Webster Park is moderate stringency similar to Old Webster, less stringent than Tuxedo Park. Webster Park overlay: historic overlay requires HPC review for exterior modifications; review focus on visible-from-street changes; less restrictive than Tuxedo Park on mechanical equipment placement (more flexibility for outdoor condenser location, line set covers, etc.); review timeframe typically 2-4 weeks. Specific Webster Park considerations: many homes built 1920s-1940s in mixed architectural styles (Tudor Revival, Colonial Revival, Craftsman); HPC focuses on preserving period character without preventing modern equipment installation; reasonable accommodation of mechanical equipment with appropriate screening or placement. For this customer’s installation: outdoor condenser placement on side-yard concrete pad behind existing fence (non-visible from street); attic equipment installation not visible externally; refrigerant line set penetrations through side-yard exterior wall (not visible from street); HPC review process was streamlined accordingly (19 days vs. 31 days for Tuxedo Park installation, 18 days for Old Webster installation). Webster Groves HPC comparison summary: Tuxedo Park most stringent (4-6 weeks review, restrictions on visible mechanical equipment); Old Webster moderate (2-4 weeks review, less restrictive on mechanical placement); Webster Park moderate similar to Old Webster (2-4 weeks review, focus on visible-from-street modifications); College Hill similar to Old Webster moderate. We have experience with all Webster Groves historic districts and design installations to receive approval; pre-application consultations with HPC staff help identify concerns; experienced approach reduces revision requests and approval timeline.

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Contact Purisync Heating and Air

For your mixed-system installation, ducted cooling addition to hydronic heating home, or attic-mounted central AC installation in Webster Groves, contact our 325 N Kirkwood Road office at (314) 338-5111. Initial consultation includes assessment of existing heating system, cooling needs analysis, equipment options across whole-home vs. targeted approaches, HPC compliance review, and written quote with itemized pricing.

• Emergency Line (24/7): (314) 338-5111
• Address: 325 N Kirkwood Rd #245, Kirkwood, MO 63122
• Email: info@purisyncheatingairconditioning.xyz
• St. Louis County Mechanical Contractor License: #MC-2014-08439-STL
• Kirkwood Business Registration: #BL-2014-1187
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