💬 Introduction: The Hidden Costs of Heat
When most homeowners think about buying a new boiler, they look at the price tag on the box. “$4,000 for a Weil-McLain CGA-5—okay, I can handle that.”
But here’s the truth: the price of the boiler itself is only part of the story.
What surprised me the most when I replaced mine wasn’t the cost of the boiler—it was everything else: installation labor, chimney liner, circulator pump, expansion tank, permits, and, of course, the ongoing gas bills.
That’s why when I talk about boiler costs, I always use the Total Cost of Ownership (TCO) mindset. You can’t just think about what you pay today—you have to consider the 15- to 20-year picture, including:
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🏷️ Equipment (boiler + accessories)
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🛠️ Installation (labor, venting, permits)
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🔥 Energy use (fuel bills each winter)
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🧹 Maintenance & repairs (annual service + occasional parts)
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⏳ Long-term value (how many years you’ll get out of it)
In this guide, I’ll break down the costs using the Weil-McLain CGA-5 Series 3 (133,000 BTU) as the baseline. I’ll also compare it with high-efficiency condensing boilers, so you can see which makes more sense for your home.
📦 Equipment Costs: What You’re Really Buying
The first line item is the easiest to understand: the boiler itself.
Weil-McLain CGA-5 (Cast Iron, Non-Condensing)
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Boiler price: $3,200–$4,500
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AFUE: 82–84%
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Lifespan: 25–35 years
High-Efficiency Condensing Boiler (e.g., Weil-McLain Ultra)
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Boiler price: $4,800–$7,000
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AFUE: 90–96%
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Lifespan: 12–15 years
👉 Reference: Modernize – Boiler Replacement Cost Guide
What’s Not Included in the Box
A boiler is just the start. Here’s what I had to add separately:
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Circulator pump ($200–$600)
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Expansion tank ($150–$300)
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Thermostat (basic or smart) ($150–$400)
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Zone valves or controllers ($300–$800 if zoned system)
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Venting kit or chimney liner ($500–$2,000 depending on system)
Real equipment total: $4,000–$6,500 for cast iron, $6,000–$9,000 for condensing.
🧰 Installation Costs: Labor & Site Prep
This is where most homeowners get sticker shock. Installing a boiler isn’t a plug-and-play job.
Common Installation Tasks
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Removing and disposing of old boiler.
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Re-piping water supply and return lines.
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Resizing or re-routing the gas line.
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Wiring controls, circulators, and thermostat.
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Installing venting (chimney liner for CGA-5, PVC for condensing).
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Filling, purging, and starting up the system.
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Safety testing (combustion, CO, draft).
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Local permits and inspections.
Labor Cost Range
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Cast iron (CGA-5): $3,000–$5,000
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Condensing: $4,000–$6,500 (more complex venting + condensate management)
👉 Reference: Boiler Installation Costs
Real installed cost (equipment + labor):
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CGA-5: $7,500–$10,500
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Condensing: $10,000–$14,500
⚡ Energy Use & Fuel Bills
Now comes the part that repeats every year: gas bills.
Efficiency Ratings
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CGA-5: 82–84% AFUE (non-condensing).
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Condensing: 90–96% AFUE (if operated at low return temps).
Annual Fuel Usage Example (2,800 sq. ft. Midwest home)
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Heating load: ~80 million BTUs/year.
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CGA-5 @ 83% AFUE → 96M BTUs input → 960 therms/year.
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Condensing @ 95% AFUE → 84M BTUs input → 840 therms/year.
At $1.20 per therm, that’s:
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CGA-5: $1,150/year
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Condensing: $1,010/year
Savings: ~$140/year.
👉 Reference: Energy.gov – Boilers
Mike’s Note
On paper, condensing saves gas. But in reality, when it’s -5°F and your system needs 180°F supply water, the efficiency gap shrinks. My CGA-5 doesn’t look bad compared to a condensing unit under heavy winter load.
🧹 Maintenance & Repairs
Every boiler needs care—but costs vary by type.
Cast Iron (CGA-5)
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Annual service: $150–$250 (inspection, cleaning, combustion check).
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Common repairs: circulator ($500 installed), relief valve ($200).
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Lifespan: 25–35 years with regular care.
Condensing
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Annual service: $200–$400 (heat exchanger cleaning, condensate neutralizer replacement).
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Common repairs: igniter ($300), control board ($800), fan ($700).
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Lifespan: 12–15 years.
👉 Reference: HVAC.com – Boiler Maintenance Guide
🏦 Incentives, Rebates & Credits
Here’s where condensing boilers shine.
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Federal IRA Tax Credit (2025): 30% up to $600 for ENERGY STAR condensing boilers.
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State rebates: $500–$2,000 (varies by state).
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Utility incentives: $300–$1,500.
👉 Reference: ENERGY STAR Rebate Finder
CGA-5: Doesn’t qualify.
Condensing: Can qualify for $1,000–$3,000 back.
📊 Long-Term Value (15-Year TCO Comparison)
Let’s add it all up.
Scenario A – Midwest (2,800 sq. ft., average gas prices)
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CGA-5:
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Installed: $9,000
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Fuel (15 yrs): $17,250
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Maintenance/repairs: $3,000
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Total = $29,250
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Condensing:
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Installed: $12,500
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Rebates: –$1,500
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Fuel (15 yrs): $15,150
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Maintenance/repairs: $4,500
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Total = $30,650
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Winner: CGA-5 by ~$1,400
Scenario B – New England (2,300 sq. ft., high gas prices, rebates available)
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Higher gas rates ($1.80/therm).
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Larger state rebates ($2,000+).
Here, the condensing boiler saves ~$4,000 over 15 years.
Scenario C – Mild Climate, Large Home
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Lower heating demand.
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Energy savings less impactful.
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Cast iron usually wins here for simplicity + lifespan.
🧑🔧 Mike’s Real-World Take
When I replaced my old boiler, I went with a Weil-McLain CGA cast iron model.
Why?
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I valued longevity (30+ years).
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I didn’t want to deal with higher repair costs of condensing boilers.
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My gas prices were moderate, so savings wouldn’t outweigh the extra $3,000+ upfront.
But I know homeowners who chose condensing and were thrilled—especially in places like Massachusetts, where rebates were huge and gas prices are high.
✅ Conclusion: Choosing Value Over Price
A boiler isn’t just about the upfront price tag. When you add equipment, installation, fuel, maintenance, and lifespan together, the real picture emerges:
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CGA-5 (cast iron): Midrange install price, steady fuel use, lower maintenance, long lifespan. Best choice for reliability and total value in moderate-cost fuel regions.
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Condensing boiler: Higher install cost, more rebates, lower fuel use, but shorter lifespan and higher repair risk. Best choice in high-cost fuel regions with generous incentives.
Mike’s rule of thumb?
👉 Always run a 15-year cost comparison before deciding.
If you want reliability and peace of mind, cast iron is tough to beat. If you want maximum efficiency and can grab rebates, condensing might pay off.
Either way, knowing the full cost breakdown helps you make the smarter call.
In the next topic we will know more about: Is 133,000 BTUs the Right Size? Mike’s Guide to Boiler Sizing for Your Home
