Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The Mighty Therm2 MT2H 1000 and MT2H 1250 are adjacent replacement-market sizes: 1,000,000 versus 1,250,000 BTU/hr input and 850,000 versus 1,065,000 BTU/hr output at 85.0% and 85.1% thermal efficiency. The 1250 steps up to a 2" gas connection.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Laars Mighty Therm2 MT2H 1000 | Laars Mighty Therm2 MT2H 1250 |
|---|---|---|
| Input | 1,000,000 BTU/hr | 1,250,000 BTU/hr |
| Output | 850,000 BTU/hr | 1,065,000 BTU/hr |
| Efficiency (thermal) | 85 % | 85.1 % |
| Gas connection | 1-1/2" | 2" |
| Water connection | 2-1/2" | 2-1/2" |
| Shipping weight | 820 lb | 915 lb |
| Firing | Two-stage, up to 4:1 | Two-stage, up to 4:1 |
| Venting | Category I fan-assisted; Category III with a listed vent system | Category I fan-assisted; Category III with a listed vent system |
The Document 1560 submittal lists the MT2H 1000 at 1,000,000 BTU/hr input, 850,000 BTU/hr output and 85.0% thermal efficiency; the MT2H 1250 lists 1,250,000 BTU/hr input, 1,065,000 BTU/hr output and 85.1%.
Gas connection steps from 1-1/2" to 2" and shipping weight from 820 to 915 lb; both keep 2-1/2" water connections and two-stage firing up to 4:1.
The pair is a direct capacity step within one line, sharing the modular construction and fan-assisted Category I venting of the Mighty Therm2 family.
Laars Heating Systems
The Laars Mighty Therm2 MT2H 1000 is a non-condensing commercial hydronic boiler rated 1,000,000 BTU/hr input and 850,000 BTU/hr output at 85% thermal efficiency with two-stage firing.
Laars Heating Systems
The Laars Mighty Therm2 MT2H 1250 is a non-condensing commercial hydronic boiler rated 1,250,000 BTU/hr input and 1,065,000 BTU/hr output at 85.1% thermal efficiency with two-stage firing.
The Document 1560 submittal prints 85.0% for the 1000 and 85.1% for the 1250.
Yes — both print 2-1/2" water connections, while the gas connection steps from 1-1/2" to 2".
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.