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Comparison

IBC IFIRE-B 300 vs IFIRE-B 400

Verdict in brief

Both the IBC IFIRE-B 300 and the IBC IFIRE-B 400 belong to the IBC Technologies IFIRE-B line of condensing boilers. Published ratings: IBC IFIRE-B 300 at 42.8–300 MBH input, 289 MBH output and 96.5% thermal efficiency; IBC IFIRE-B 400 at 57.1–399 MBH input, 383 MBH output and 96% thermal efficiency. IBC IFIRE-B 400 lists 99 MBH more input than IBC IFIRE-B 300 (399 MBH against 300 MBH). IBC IFIRE-B 300 carries the higher published thermal efficiency at 96.5%, against 96%.

Side by side

Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.

Comparison of IBC IFIRE-B 300 and IBC IFIRE-B 400
SpecificationIBC IFIRE-B 300IBC IFIRE-B 400
CSA input (NG or LP), minimum42.8 MBH57.1 MBH
CSA input (NG or LP), maximum300 MBH399 MBH
CSA output, minimum41.3 MBH54.7 MBH
CSA output, maximum289 MBH383 MBH
Efficiency (thermal)96.5 %96 %
Turndown7:17:1
VentingCategory IV or direct vent; PVC, CPVC, polypropylene or stainless steel up to 100 ftCategory IV or direct vent; PVC, CPVC, polypropylene or stainless steel up to 100 ft
Gas supply pressureMin 4" w.c. NG / 8" w.c. LP; max 10.5" w.c. NG / 13" w.c. LPMin 4" w.c. NG / 8" w.c. LP; max 10.5" w.c. NG / 13" w.c. LP
Ambient temperature, high150 °F150 °F
ControlVERSA IC touchscreenVERSA IC touchscreen

What actually separates them

Published ratings: the IBC IFIRE-B 300 is rated 42.8–300 MBH input, 289 MBH output and 96.5% thermal efficiency; the IBC IFIRE-B 400 is rated 57.1–399 MBH input, 383 MBH output and 96% thermal efficiency. IBC IFIRE-B 400 lists 99 MBH more input than IBC IFIRE-B 300 (399 MBH against 300 MBH). IBC IFIRE-B 300 carries the higher published thermal efficiency at 96.5%, against 96%.

Both records print the same turndown (7:1), venting (Category IV or direct vent; PVC, CPVC, polypropylene or stainless steel up to 100 ft), gas supply pressure (Min 4" w.c. NG / 8" w.c. LP; max 10.5" w.c. NG / 13" w.c. LP) and ambient temperature, high (150 °F), per the cited sources.

IBC Technologies

IBC IFIRE-B 300

CurrentSold in Canada
Input
42.8–300 MBH
Output (max)
289 MBH
AFUE
—

The IBC IFIRE-B 300 is a commercial condensing boiler rated 42.8-300 MBH CSA input (NG or LP) and 41.3-289 MBH CSA output at 96.5% thermal efficiency, with the VERSA IC touchscreen control and 7:1 turndown.

Natural gasPropaneHeating-only
Specifications, manuals and service

IBC Technologies

IBC IFIRE-B 400

CurrentSold in Canada
Input
57.1–399 MBH
Output (max)
383 MBH
AFUE
—

The IBC IFIRE-B 400 is a commercial condensing boiler rated 57.1-399 MBH CSA input (NG or LP) and 54.7-383 MBH CSA output at 96% thermal efficiency, with the VERSA IC touchscreen control and 7:1 turndown.

Natural gasPropaneHeating-only
Specifications, manuals and service

Frequently asked questions

Which of the two has the higher maximum input?

The IBC IFIRE-B 400 lists 399 MBH, against 300 MBH on the IBC IFIRE-B 300, per the cited documentation.

Which model is more efficient?

The IBC IFIRE-B 300 carries the higher published thermal efficiency at 96.5%, against 96%.

Not sure which one fits your home?

A consultation includes a heat-loss review so the size is right the first time.

On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.

Call 778-909-5731Request a consultation

Related

Sources and verification

Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.

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