When my old boiler finally gave out, I knew I needed something powerful enough to handle my 3,400 sq. ft. colonial in Pennsylvania. After talking to contractors and doing hours of research, three names kept coming up again and again: Weil-McLain, Burnham, and Slant/Fin.
Each brand offers gas boilers in the 166,000 BTU range—perfect for larger homes or multi-family setups. But which one is right for you? I’ll share what I learned while shopping, how these brands compare, and why I ultimately went with Weil-McLain.
Weil-McLain CGa-6 Series 3 166,000 BTU Cast Iron Natural Gas Boiler
🏠 Why 166,000 BTUs Matters
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A boiler this size is designed for homes in the 3,000–5,000 sq. ft. range.
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It can handle multiple heating zones, making it ideal for multi-story or larger layouts.
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It’s also used in two-family homes or small commercial spaces.
💡 Samantha’s note: Oversizing is just as bad as undersizing—always confirm with a Manual J load calculation before you commit.
🔗 Energy Vanguard – Manual J Sizing
🔩 The Three Big Players
🔹 Weil-McLain (CGA-6 Series)
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Type: Cast iron, natural gas, non-condensing
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AFUE: ~82%
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Strengths: Longevity, reliability, parts availability
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Lifespan: 25–30 years with proper maintenance
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Warranty: 10 years heat exchanger (limited)
👉 Why I liked it: Built like a tank, and I wanted something that could last decades.
🔹 Burnham (U.S. Boiler Company)
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Type: Cast iron & condensing options
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AFUE: 82% (cast iron) to 95%+ (condensing)
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Strengths: Rebates/credits eligible with condensing models
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Lifespan: 20–25 years (cast iron), 15–20 (condensing)
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Warranty: 10 years on most models, some limited lifetime
👉 Why I considered it: Burnham’s condensing boilers qualified for federal tax credits—something Weil-McLain’s CGA-6 couldn’t.
🔹 Slant/Fin
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Type: Cast iron, standard efficiency
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AFUE: ~82%
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Strengths: Lower upfront cost, wide distributor network
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Lifespan: 15–20 years
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Warranty: 10 years, more limited in scope than others
👉 Why I hesitated: Price was attractive, but reviews suggested shorter lifespan compared to Weil-McLain or Burnham.
⚖️ Side-by-Side Comparison
| Feature | Weil-McLain CGA-6 | Burnham (Series 2 / Alpine) | Slant/Fin Galaxy |
|---|---|---|---|
| AFUE | 82% | 82% (cast iron) – 95%+ (condensing) | 82% |
| Material | Cast iron | Cast iron or stainless steel | Cast iron |
| Lifespan | 25–30 years | 20–25 (cast iron), 15–20 (condensing) | 15–20 years |
| Rebate Eligible | ❌ (standard models) | ✅ (condensing) | ❌ |
| Cost (equipment) | $4,000–$4,800 | $4,000–$6,000 | $3,500–$4,500 |
| Best For | Long-term reliability | Efficiency + rebate seekers | Budget-conscious installs |
🔧 Installation Considerations
Weil-McLain
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Heavy cast iron sections make installation harder, but once in place, they’re stable and quiet.
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Requires chimney venting (unless paired with upgrades).
Burnham
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Condensing units require PVC venting, condensate drain, and more complex install.
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Cast iron models similar to Weil-McLain.
Slant/Fin
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Lighter than Weil-McLain, easier to move into basements.
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Still needs chimney venting.
🧰 Maintenance and Service
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Weil-McLain: Easy to find parts; service techs are familiar with the brand. Annual maintenance is straightforward.
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Burnham: Condensing models require more detailed annual cleaning. Cast iron similar to Weil-McLain.
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Slant/Fin: Parts can be harder to find in certain regions; lifespan shorter if water chemistry isn’t maintained.
🔗 DOE – Boiler Maintenance Guide
💵 Cost Breakdown
Weil-McLain CGA-6
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Equipment: $4,300
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Installation: $5,200
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Accessories: $2,000
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Total: ~$11,500
Burnham (Cast Iron)
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Equipment: $4,500
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Installation: $5,500
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Accessories: $2,000
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Total: ~$12,000
Burnham (Condensing)
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Equipment: $5,800
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Installation: $6,000 (extra venting)
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Accessories: $2,500
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Total: ~$14,300 (but rebates apply)
Slant/Fin
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Equipment: $3,800
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Installation: $5,000
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Accessories: $1,800
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Total: ~$10,600
👉 Burnham’s condensing option was pricier upfront, but eligible for $1,600+ in rebates and credits.
🔗 ENERGY STAR – Tax Credits for Boilers
📝 Samantha’s Real-World Choice
For my colonial in Pennsylvania, here’s how I decided:
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Weil-McLain: Won on durability. I didn’t want to replace my boiler again in 15 years.
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Burnham: Attractive for rebates, but I wasn’t ready for the complexity of a condensing system.
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Slant/Fin: Too many reviews about shorter lifespan for me to risk it.
👉 Final decision: Weil-McLain CGA-6 cast iron boiler. Solid, proven, and a perfect match for my home.
✅ Key Takeaways
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Weil-McLain = best for long-term reliability and homeowners planning to stay in place for decades.
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Burnham = best for efficiency seekers who want rebates and can handle condensing boiler maintenance.
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Slant/Fin = best for budget buyers who want lower upfront cost but accept shorter lifespan.
💡 Samantha’s advice: Ask yourself what matters most: upfront savings, long-term durability, or rebates. Your answer will point you to the right boiler.
In the next topic we will know more about: Noise, Space & Design: Will a Weil-McLain 166,000 BTU Boiler Fit Your Home Setup?
