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 EVG-299 and EVG-399 are the two largest Evergreens and the line's only real efficiency question: the 299 is DOE-rated 95.0% AFUE, while the 399's 96.5% figure is combustion efficiency with gross output — an asterisked rating, not an AFUE. Capacity steps from 299 to 399 MBH at the same 260 lb shipping weight.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Weil-McLain Evergreen EVG-299 | Weil-McLain Evergreen EVG-399 |
|---|---|---|
| Input, maximum | 299 MBH | 399 MBH |
| DOE heating capacity | 280 MBH | 383 MBH |
| Net AHRI water rating | 243 MBH | 333 MBH |
| Turndown | 10:1 | 10:1 |
| Weight | 260 lb | 260 lb |
| Boiler water content | 7 gal | 6.7 gal |
| Venting | 4" PVC, CPVC, polypropylene or AL29-4C stainless steel (Category IV); 4" pipe only on the 299 | 4" PVC, CPVC, polypropylene or AL29-4C stainless steel (Category IV); 4" pipe only on the 399 |
Both models run the 220-399 platform with 10:1 turndown, 4" venting only, 1-1/2" NPT supply and return tappings, 3/4" NPT gas and the same 260 lb shipping weight. The 399 steps input from 299 to 399 MBH, gross output from 280 to 383 MBH and the net AHRI rating from 243 to 333 MBH.
The efficiency story is where buyers must read the asterisk: the 299 is DOE-rated at 95.0% AFUE, while the 399's 96.5% figure in the manual and US table is combustion efficiency with 383 MBH gross output — not a seasonal efficiency. The CA residential page's "96.5% AFUE" spec block drops that footnote, which is why Boilers.ca treats the two figures separately.
Water content actually drops at the top of the line — 6.7 gallons on the 399 against 7.0 on the 299 — and both need 4" vent routes to 100 ft. The 399 earns its place when the load genuinely exceeds the 299's 280 MBH of output; the 299 is the largest DOE-AFUE-rated Evergreen.
Weil-McLain
The Evergreen EVG-299 delivers 299 MBH of input and 280 MBH of DOE heating capacity at 95.0% AFUE on the 220-399 platform, with 4" venting only and 7.0 gallons of water content.
Weil-McLain
The Evergreen EVG-399 tops the platform at 399 MBH input: the manual's 96.5% figure is combustion efficiency with gross output — not AFUE — so the CA page's "96.5% AFUE" claim misstates the rating of this 6.7-gallon, 260 lb boiler.
Its 96.5% figure is combustion efficiency with gross output, not a DOE AFUE; the 299 carries a real 95.0% AFUE rating. The two figures are not comparable as seasonal efficiencies.
Input rises from 299 to 399 MBH and net AHRI rating from 243 to 333 MBH, at the same 260 lb shipping weight.
4" pipe only on both, to 100 feet each for vent and air.
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 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.