Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The BMK 1000 and BMK 1500 both print 20:1 turndown, but stepping up doubles the dry weight (700 lb to 1,406 lb), deepens the cabinet from 25" to 43.6", raises the minimum input from 50 to 75 MBH, moves to 2" gas and 4" water connections, and trades 96.8% thermal efficiency for 94.6% while adding 480 MBH of output range.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | AERCO Benchmark 1000 | AERCO Benchmark 1500 |
|---|---|---|
| Min. input | 50 MBH | 75 MBH |
| Max. input | 1,000 MBH | 1,500 MBH |
| Max. output | 960 MBH | 1,440 MBH |
| Thermal efficiency (80–180°F) | 96.8 % | 94.6 % |
| Efficiency range | 87–98 % | 87–98 % |
| Turndown ratio | 20:1 (5%) | 20:1 (5%) |
| Gas connection (NPT) | 1" | 2" |
| Water connection (flanged) | 3" | 4" |
| Weight, dry | 700 lb | 1,406 lb |
| Shipping weight | 900 lb | 1,606 lb |
| Width (A) | 28 in | 28 in |
| Depth (B) | 25 in | 43.6 in |
| Height (C) | 78 in | 78 in |
The 1500 exists for loads the 1000 cannot carry: AERCO prints 1305–1440 MBH of output against 870–960 MBH on the 1000. Both modulate at 20:1 (5%), so the low-load behaviour is comparable, but the 1500's minimum input is 75 MBH versus 50 MBH, so in a plant whose load is comfortably under 500 MBH the smaller boiler cycles less.
The efficiency ranking flips with size: the 1000 is the highest row in the Benchmark table at 96.8% thermal efficiency, while the 1500 prints 94.6% (both within the same 87%–98% range).
The physical step is substantial: dry weight doubles to 1,406 lb (shipping 1,606 lb), depth grows from 25" to 43.6", and the connections step up to 2" NPT gas and 4" flanged water. Plan rigging and near-boiler piping accordingly; width and height stay 28" and 78".
AERCO (Watts)
The AERCO Benchmark 1000 (BMK 1000) is a condensing gas-fired firetube commercial boiler rated 1000 MBH maximum input and a 870–960 MBH output range in AERCO's published ratings table, at 96.8% thermal efficiency (87%–98% range), with 20:1 (5%) turndown and a 700 lb dry weight.
AERCO (Watts)
The AERCO Benchmark 1500 (BMK 1500) is a condensing gas-fired firetube commercial boiler rated 1500 MBH maximum input and a 1305–1440 MBH output range in AERCO's published ratings table, at 94.6% thermal efficiency (87%–98% range), with 20:1 (5%) turndown and a 1406 lb dry weight.
The BMK 1000 prints 96.8% thermal efficiency and the BMK 1500 94.6% at 80º–180ºF, per AERCO's TDS ratings table.
Yes — AERCO prints 20:1 (5%) for both the BMK 1000 and BMK 1500.
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.