Meramec Highlands Furnace Replacement: 1898 Victorian Boiler Upgrade

Case study summary: 1898 Victorian home in Kirkwood’s Meramec Highlands historic district with original hydronic heating system; replaced aging gas boiler (1987 vintage) with modern Weil-McLain Ultra 230 95% AFUE condensing boiler while preserving original cast-iron radiator distribution; total project cost $11,400; completed in 1.5 days during October 2024 with full Kirkwood Historic Preservation Commission review. Outcome: 35-40% reduction in heating gas consumption versus previous equipment; complete preservation of original radiator aesthetic; customer satisfaction high with installation discretion and final result.

The Home

• Built: 1898
• Style: Queen Anne Victorian
• Location: Meramec Highlands historic district, Kirkwood, MO 63122
• Size: 2,640 sf across three floors plus full basement
• Construction: Brick exterior with substantial plaster wall interior; original wood trim, baseboards, and architectural detailing throughout
• Heating system: Hydronic distribution with 11 cast-iron radiators across all three floors
• Existing boiler: Gas-fired Weil-McLain CGS-5 from 1987 (37 years old at time of replacement); 80% AFUE non-condensing equipment originally replacing earlier coal-fired boiler from 1898
• Cooling: Existing Mitsubishi ductless mini-split system installed 2018 (3-zone, no changes during this project)

The Situation

Customer contacted us in September 2024 after their boiler failed during a brief cold snap (low overnight temperatures in mid-September). Initial diagnostic identified multiple failing components: leaking pressure relief valve, waterlogged expansion tank, deteriorating cast-iron section showing internal corrosion via inspection, and excessive cycling indicating control board issues. Repair-versus-replace assessment:

• Estimated cumulative repair cost if pursued piece-by-piece: $1,800–$3,200 over 12-18 months as additional components reached failure
• Equipment age: 37 years old, substantially past typical boiler service life (30-50 years for cast-iron section boilers with proper maintenance, though this equipment had been showing accelerating decline over recent 5 years)
• Internal corrosion indicators: visible rust in inspection openings suggesting section life remaining 2-5 years
• Efficiency: 80% AFUE non-condensing technology substantially less efficient than modern 95% AFUE condensing equipment

Customer decision: replacement rather than continued piecemeal repair. Customer priorities for replacement: preserve original radiator system and aesthetic appearance throughout home; maintain compatibility with historic preservation requirements for Meramec Highlands district; minimize installation disruption to home; maximize efficiency improvement for long-term operating cost reduction.

The Equipment Selection

After discussing options with customer:

Weil-McLain Ultra 230 (Selected)

• AFUE: 95%
• Capacity: 230,000 BTU/hr input; sized for the home’s heating load of approximately 175,000 BTU/hr at design temperature (3°F)
• Technology: Modulating gas valve with stainless steel heat exchanger; outdoor temperature reset capability
• Warranty: 12 years on heat exchanger, 10 years on parts
• Why selected: Best balance of efficiency, reliability track record, and compatibility with existing hydronic distribution system; Weil-McLain’s long history of cast-iron boilers reassuring to customer; modulating capability provides better part-load efficiency than two-stage equipment

Alternative Equipment Considered

• Burnham ESC 99 AFUE: Higher efficiency but premium pricing made simple payback longer; customer prioritized total cost over absolute efficiency maximization
• Lochinvar Knight 96 AFUE: Competitive equipment; selected against based on customer preference for Weil-McLain brand familiarity
• Buderus GB142 95 AFUE: German engineering; premium pricing didn’t justify benefit for this application

The Project Scope

Pre-Installation Coordination

• Kirkwood Historic Preservation Commission review: Submitted equipment specifications, photographs of proposed vent termination location, and condensate routing plan for preservation review; approval received in 18 days; no modifications required to proposed plan
• Kirkwood Public Works permit: Pulled within 3 business days of preservation approval
• Equipment ordering: 7 business days from order to delivery

Installation Day 1 (October 21, 2024)

• Existing boiler isolation and shutdown
• Old equipment removal: hauled away same day; cast-iron sections separated for recycling per Kirkwood disposal requirements
• Boiler pad preparation: existing concrete pad inspected and verified adequate for new equipment weight
• New Weil-McLain Ultra 230 placement in basement mechanical room (same location as previous equipment)
• Gas line connection: existing ¾" black iron pipe verified adequate for new equipment input rate
• PVC venting installation: new dual-pipe sealed combustion venting through basement wall to side-yard termination (preservation review approved location)
• Hydronic loop connection: connection to existing supply and return mains; existing piping in good condition requiring no modifications
• Expansion tank replacement: 4.4 gallon Amtrol Extrol bladder tank (new) replacing failing 1987 expansion tank
• Pressure relief valve installation: 30 psi residential standard
• Circulator pump installation: new Taco 007 cast-iron circulator pump replacing 1987 vintage pump
• System filling and bleeding: glycol-free water; air bleeding from highest radiator throughout afternoon
• End of Day 1: Equipment installed, system pressurized to 15 psi cold, initial commissioning incomplete

Installation Day 2 (October 22, 2024)

• Morning system verification: cold pressure 15 psi maintained overnight; no leaks visible
• Initial firing: equipment fired and cycled through startup sequence
• Combustion analysis with Bacharach Fyrite Insight Plus: CO 28 ppm air-free (well under 100 ppm safety threshold), CO2 9.4%, O2 6.2% — all readings within manufacturer specifications
• Modulating gas valve calibration: verified modulation across full capacity range (40-100%)
• Outdoor temperature reset configuration: programmed for St. Louis climate (design temperature 3°F, outdoor reset target 90°F supply water temperature at 50°F outdoor, 180°F supply at 3°F outdoor)
• Radiator operation verification: confirmed circulation to all 11 radiators across three floors; air bleeding repeated for highest radiators showing initial air-binding
• System pressure verification under operation: 22-25 psi hot operating pressure (within normal range)
• Customer walk-through: explained operation, thermostat programming, maintenance schedule, and warranty registration
• Documentation: installation completion paperwork, equipment registration with Weil-McLain, manufacturer warranty activation

Inspection (October 25, 2024)

• Kirkwood Public Works inspector visit 3 business days after installation
• Combustion analysis verified to inspector with Bacharach printout
• Installation passed inspection without modifications

The Pricing

• Weil-McLain Ultra 230 boiler: $4,800 equipment cost
• Amtrol Extrol expansion tank: $140
• Taco 007 circulator pump: $280
• PVC venting and combustion air piping: $340
• Installation labor (1.5 days, 2 technicians): $4,800
• Permit fee through Kirkwood Public Works: $180
• Old equipment removal and disposal: $260
• Bacharach combustion analysis and commissioning: $200
• Kirkwood Historic Preservation Commission review fee: $80
• Miscellaneous fittings, pipe, and consumables: $320
• Total project cost: $11,400

This pricing fell within our standard range for similar historic home boiler replacements ($7,800–$12,800 for residential historic home hydronic boiler installations).

The Outcome

Comfort and Operation

• Heating consistency: customer reports more even heat across all three floors than previous equipment, attributed to modulating operation providing longer cycles with sustained heat delivery to upper floors
• Quieter operation: new equipment is substantially quieter than previous boiler, both during operation and during cycling transitions
• Outdoor reset benefit: customer reports more comfortable mild-weather operation with system delivering lower supply water temperature rather than the on/off cycling of previous equipment at full output

Energy Savings

• First-winter gas consumption (Nov 2024 – Mar 2025): 1,840 therms versus previous winter (Nov 2023 – Mar 2024) consumption of 2,920 therms — 37% reduction
• Annual gas savings at $1.20/therm: approximately $1,296 reduction in annual heating costs
• Simple payback on installation: approximately 8.8 years on energy savings alone; faster when including avoided continued repair costs on aging equipment

Customer Feedback

Customer reported satisfaction with several aspects: installation discretion during work (protective materials throughout basement and stairwell, daily cleanup, no impact on upper floors of home); preservation of original radiator aesthetic with no modifications to visible heating elements; smooth handling of Historic Preservation Commission review without customer involvement beyond initial documentation; final operation noticeably improved over previous equipment.

Ongoing Service

Customer enrolled in our maintenance plan covering both the new boiler and existing Mitsubishi ductless system; annual maintenance scheduled for both systems together each fall before heating season.

Frequently Asked Questions

Could you have replaced just the failing components on the old boiler instead of full replacement?

Yes, we could have done piecemeal repair — the pressure relief valve ($180-$340), expansion tank ($240-$540), and control board ($340-$980) could each have been replaced independently. We discussed this option with the customer explicitly during diagnostic. Reasons we recommended replacement over piecemeal repair: cumulative repair cost across all failing components ($1,800-$3,200 over 12-18 months) approached substantial fraction of replacement cost; internal corrosion indicators in the cast-iron sections suggested 2-5 years remaining section life regardless of other component repairs (so customer would be facing complete replacement within that timeframe anyway, after spending substantially on interim repairs); 37-year-old equipment at 80% AFUE provided substantially worse operating economics than modern 95% AFUE replacement; customer’s stated priority of long-term efficiency improvement favored replacement timing now. Customer chose replacement based on this honest assessment of repair-versus-replace economics. We don’t recommend replacement when single component repair makes economic sense on equipment with substantial remaining service life — but on 37-year-old equipment with multiple components failing and internal corrosion visible, replacement was the better recommendation.

Why didn’t you switch to forced-air during the boiler replacement?

Several reasons specific to this home. First, converting from hydronic to forced-air would have required substantial ductwork installation throughout a historic home with limited installation routes — this kind of conversion typically runs $14,000-$24,000+ for a 2,640 sf historic home and would have substantially compromised the architectural integrity that the customer specifically wanted to preserve. Second, the original cast-iron radiators provide superior comfort characteristics (radiant heat distribution, no air movement, no dust circulation, very even temperatures throughout the home) that the customer valued and wanted to keep. Third, the existing hydronic distribution system was in good condition requiring no modifications — replacing only the boiler and a few wear components (expansion tank, pressure relief valve, circulator pump) was substantially more economical than removing functional infrastructure to install something new. Fourth, the existing ductless mini-split system installed in 2018 already provided AC and supplemental heating, so the customer didn’t need forced-air for cooling either. Combining all these factors, hydronic preservation was clearly the better path for this home. For homes where existing hydronic infrastructure has substantial problems beyond the boiler, or where the customer specifically wants forced-air for AC reasons, the conversion economics can sometimes work — but for most historic Kirkwood homes with functional hydronic systems, preservation is the right choice.

How disruptive was the installation to the family living in the home?

Less disruptive than the customer expected. Several factors contributed to manageable disruption. First, the work was concentrated in the basement mechanical room (where the equipment is located) and along the routes from there to the side-yard vent termination — the upper floors of the home were not affected by installation activity. Second, we use extensive protective materials (drop cloths on basement floor and stairwell, plastic sheeting at basement entrance to prevent dust migration, foot protection for technicians moving through home) to maintain finish protection throughout the work. Third, we worked normal business hours (8 AM – 5 PM both days) with no overnight or weekend work requiring family schedule adjustment. Fourth, we coordinated heating provision during the installation: since the work was done in late October during mild weather (high 60s°F to low 70s°F daytime, low 50s°F overnight), the home didn’t need heating during the 36-hour installation window between old equipment shutdown and new equipment startup; we recommended timing for similar mild-weather windows rather than performing installation during cold weather requiring temporary heating arrangements. Fifth, the existing Mitsubishi ductless system continued to operate for supplemental heating in specific rooms during the installation window if needed. Total disruption to family: limited use of basement during work, normal home function maintained on all upper floors, brief discussion with technicians during pre-work walk-through and customer walk-through on completion.

What happens if my home’s boiler is older but still working?

Depends on equipment age, condition, and customer priorities. Boilers between 15-25 years old with no major issues are typically running fine and don’t need replacement urgently — these are good candidates for maintenance plans that include annual tune-ups (combustion analysis, pressure verification, circulator pump inspection, controls testing) to catch developing issues before they become emergencies. Boilers 25-35 years old start showing increasing component failures (circulator pumps, expansion tanks, pressure relief valves are typical) but the cast-iron heat exchanger sections themselves can last 50+ years; piecemeal component replacement makes sense during this period while the heat exchanger remains in good condition. Boilers 35+ years old (like this case study) are approaching or past typical service life — replacement consideration becomes appropriate, with decision factors including: visible internal corrosion or rust in inspection openings; multiple components failing or showing pre-failure indicators within short timeframe; efficiency improvement economics making replacement attractive; customer ownership timeline supporting investment payback. For your specific situation, we provide assessment during diagnostic that includes equipment age, condition indicators, repair-versus-replace economics, and recommendation honest to your situation — not pushing replacement when piecemeal repair makes sense, but not extending repair on equipment near the end of service life when replacement provides better long-term value.

Does the historic preservation review process always go this smoothly?

Most boiler installations in Kirkwood historic districts pass preservation review without modifications, like this case study — but not all. Boiler installations are typically less complex from a preservation standpoint than AC installations because the equipment is interior (in basement mechanical rooms) with limited exterior changes. The main preservation-sensitive elements of boiler installation: vent termination location (PVC vent through exterior wall to outdoors); condensate routing (typically internal to basement floor drain or condensate pump, with minimal preservation concern); combustion air intake location (paired with vent termination for sealed combustion equipment). When preservation review modifications are required, they typically involve: vent termination location changes (moving from street-visible to side-yard or rear-yard location); paint/color matching for vent terminations to blend with siding; vent cover design changes for terminations in highly visible locations; coordination with other approved exterior modifications. The Kirkwood Historic Preservation Commission generally supports HVAC modernization done in ways that respect historic character; their concern is visible exterior impact rather than the interior equipment itself. Webster Groves preservation review is more stringent than Kirkwood’s, with typically 2-6 week review timelines and more frequent modification requirements; both cities have specific requirements documented on their municipal websites. We handle the preservation review process for the customer in both cities; the customer’s involvement is limited to providing photographs of the home and signing approval forms.

---

Contact Purisync Heating and Air

For your historic home boiler replacement or hydronic system modernization, contact our 325 N Kirkwood Road office at (314) 338-5111. Initial consultation includes equipment condition assessment, repair-versus-replace economic analysis, preservation review planning for historic district homes, and written quote with itemized pricing across equipment options.

• 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
• EPA Section 608 Universal: #608U-2014-385721

Contact Us →

Office Hours

• Emergency Service: 24 hours a day, 7 days a week
• Office Staff: Monday – Saturday, 9:00 AM – 5:00 PM
• Closed: Sundays and State/Federal Holidays (emergency line always active)