Standard Efficiency (Cast Iron) Hot Water Gas Boilers

Standard efficiency hot water (hydronic) cast iron gas boilers with chimney vent or direct/power vent options. Available in a variety of sizes for residential and commercial needs.
Note: All boiler BTU ratings listed are Net AHRI or Net IBR (which are the same) for ease of comparison. For Input BTU Rating - see individual product listing.

About Cast Iron Gas Boilers

The terms "cast iron gas boiler", "standard gas boiler" and "standard efficiency gas boiler" all refer to the same type of boiler, which utilizes a cast iron heat exchanger to heat water (with about ~85% efficiency), commonly vented through an existing chimney (sometimes though a wall - direct/power vent) and uses natural or propane gas as a fuel.
Traditional hot water gas boilers are straightforward, reliable and require less maintenance comparing to the newer high-efficiency (condensing) type. What they lack in efficiency (85% on avg vs 95% avg. for high-efficiency/condensing), they make up in more attractive upfront cost, long-term reliability and low cost of service and/or repair.
Standard gas boilers are most commonly chimney vented and will require a functioning chimney to operate. They are frequently purchased as a replacement for old/outdated/malfunctioning boilers due to low cost and ease of replacement (no need for complex re-piping, drilling new holes in walls, etc.). Some models are available in direct vent (sealed combustion - using outdoor air) or power vent (using indoor air for combustion) - where chimney is not available.
Due to their weight, all cast iron gas boilers are floor-standing and will generally require more floor space for piping, venting and components, however, compact models are also available for low-ceiling basements, small mechanical rooms, etc.

Frequently Asked Questions

Q: How to maximize cast iron gas boiler efficiency?
A: There are many ways to increase heating efficiency and reduce heating bills, including:
1. Use pipe insulation on all exposed water pipes to reduce both operating and standby heat loss.
2. Install a magnetic boiler filter - since cast iron boilers normally produce rust, the filter will catch & retain (filter out) the rust from system water, allowing for better and more efficienct heat transfer.
3. Use a high efficiency circulator pump instead of a standard one (majority boiler models we sell come with a high efficiency circulator).
4. Use a better thermostat, which offers better means to control energy usage.

Q: What kind of vent pipe does a cast iron gas boiler need?
A: All chimney-vented cast iron gas boilers use standard (Category I) galvanized chimney vent pipe (same type used for water heaters, furnaces, etc.). The exception are boilers with integrated fan (power vent/direct vent type) - these must use Category III vent pipe (stainless steel with gas-tight gaskets).

Q: Are these boilers "packaged" or "knock-down"?
A: We only sell packaged, fully assembled boilers - complete with dampers, draft hoods, controls (gas valves, LWCO's, etc.), circulators (Taco or Grundfos), pressure relief valves, gauges, drain valves, etc. As with all other boiler brands and types, they will require purchase of standard hot water boiler system components, such as an expansion tank, boiler fill valve (pressure reducing & backflow), air eliminator/scoop, etc.