Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
Boilers.ca is a brand of ROMA Heating & Cooling · Licensed gas contractor LGA0202903
Comparison
Verdict in brief
The GVX-105 and GVX-140 are adjacent sizes of Smith's discontinued GVX residential cast-iron water boiler line: 105 versus 140 MBH AGA input, 87 versus 116 MBH DOE heating capacity and 76 versus 101 MBH net I=B=R, both at 82.0% AFUE. The GVX model offers an optional power vent, which matters when the replacement location has no chimney.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Smith GVX-105 | Smith GVX-140 |
|---|---|---|
| AGA input (as printed) | 105 MBH | 140 MBH |
| DOE heating capacity | 87 MBH | 116 MBH |
| Net I=B=R water rating | 76 MBH | 101 MBH |
| AFUE | 82 % | 82 % |
| Supply / return tappings | not printed in the captured documents | not printed in the captured documents |
The GVX line is the power-vent-capable sibling of the GBX in Smith's discontinued residential catalogue. BSG-10 prints 105 MBH AGA input / 87 MBH DOE capacity / 76 MBH net for the GVX-105 and 140 / 116 / 101 for the GVX-140; both sizes list 82.0% AFUE. The series copy notes the optional power vent on the GVX model, which allows sidewall venting where a chimney is unavailable.
No per-size connection table for the GVX was captured in the official documents; only the BSG-10 ratings are printed per model. The GBX manual documents 1-1/2" supply and 1-1/4" return tappings for its sibling line, but the GVX records deliberately do not copy that across — the connection spec states that no GVX table was printed rather than guessing.
For legacy planning, the capacity step between the two is about 29 MBH of AGA input and 25 MBH of net rating, with no efficiency gain from the larger size. A replacement decision should start from the home's current heat loss and the venting path available, which is a job for a licensed heating contractor.
Smith Cast Iron Boilers
The Smith GVX-105 is a discontinued residential cast-iron water boiler rated 105 MBH AGA input with 87 MBH DOE heating capacity, 76 MBH net I=B=R and 82% AFUE, offered with an optional power vent.
Smith Cast Iron Boilers
The Smith GVX-140 is a discontinued residential cast-iron water boiler rated 140 MBH AGA input with 116 MBH DOE heating capacity, 101 MBH net I=B=R and 82% AFUE, offered with an optional power vent.
Capacity: 105 versus 140 MBH AGA input, 87 versus 116 MBH DOE heating capacity and 76 versus 101 MBH net I=B=R, per BSG-10. Both are rated 82.0% AFUE.
BSG-10 notes the GVX model offers an optional power vent; both lines share the same published rating structure and are marked '(Discontinued)' in Smith's site navigation.
Not in the documents captured for this batch. The model records state that no per-size GVX connection table was printed rather than assuming the GBX sizes.
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.