Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
Both the Weil-McLain CGi-25 and the Weil-McLain CGi-3 belong to the Weil-McLain CGi (cast iron) line of non-condensing boilers. The Weil-McLain CGi-25 is documented at 48 MBH input, 41 MBH output and 84% AFUE, while the Weil-McLain CGi-3 is documented at 58 MBH input, 49 MBH output and 84% AFUE. Weil-McLain CGi-3 lists 10 MBH more input than Weil-McLain CGi-25 (58 MBH against 48 MBH). Both list the same published AFUE of 84%.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Weil-McLain CGi-25 | Weil-McLain CGi-3 |
|---|---|---|
| Input, maximum | 48 MBH | 58 MBH |
| DOE heating capacity | 41 MBH | 49 MBH |
| Efficiency (AFUE) | 84 % | 84 % |
| Venting | Category I B-vent (chimney) or Category III AL29-4C stainless steel (sidewall) | Category I B-vent (chimney) or Category III AL29-4C stainless steel (sidewall) |
| Fuel | Natural gas or propane | Natural gas or propane |
| Net AHRI water rating | 36 MBH | 43 MBH |
Published ratings: the Weil-McLain CGi-25 is rated 48 MBH input, 41 MBH output and 84% AFUE; the Weil-McLain CGi-3 is rated 58 MBH input, 49 MBH output and 84% AFUE. Weil-McLain CGi-3 lists 10 MBH more input than Weil-McLain CGi-25 (58 MBH against 48 MBH). Both list the same published AFUE of 84%.
Both records print the same AFUE (84%), venting (Category I B-vent (chimney) or Category III AL29-4C stainless steel (sidewall)) and fuel (Natural gas or propane), per the cited sources.
Weil-McLain
The CGi-25 is the smallest CGi Series 5 size, from the cast iron line Canada discontinued in 2023: 48 MBH CSA input, 41 MBH DOE heating capacity and a 36 MBH net AHRI rating at 84% AFUE.
Weil-McLain
The CGi-3 is the second-smallest CGi Series 5 size of the cast iron line Canada discontinued in 2023: 58 MBH CSA input, 49 MBH DOE heating capacity and a 43 MBH net AHRI rating at 84% AFUE.
The Weil-McLain CGi-3 lists 58 MBH, against 48 MBH on the Weil-McLain CGi-25, per the cited documentation.
Both list the same AFUE of 84%.
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.
Sources and verification
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.