Compare ComfortBilt HP22 vs Castle Serenity
ComfortBilt HP22 vs Castle Serenity Main heater or zone heater
Both are sold online at a published price. The HP22 tests at 12,820 to 40,689 BTU/hr and 81% HHV; the Castle Serenity 12327 tests at 9,831 to 22,266 BTU/hr and 70% HHV, at about $1,000 less.
Where to buy: no retailer links on this page yet. Prices below are the makers' own figures on the date shown.
Short answer: The HP22 is the stove to buy if you want a pellet stove to carry a main living area or a small house. The Serenity suits one room, a basement or a cabin, where 22,000 BTU/hr is enough and the lower price matters.
EPA Certification Side by Side
| ComfortBilt HP22 | Castle Serenity | |
|---|---|---|
| Type | Pellet stove | Pellet stove |
| Tested output (BTU/hr) | 12,820–40,689 EPAchecked 2026-10-21 | 9,831–22,266 EPAchecked 2026-10-21 |
| Efficiency (HHV) | 81% | 70% |
| Particulate | 1 g/hr | 1.1 g/hr |
| Carbon monoxide | not listed | not listed |
| Firebox | – | – |
| Test fuel | Wood Pellets | Wood Pellets |
Maker Claims Side by Side
| ComfortBilt HP22 | Castle Serenity | |
|---|---|---|
| Advertised heat output | 9,696–40,689 BTU/hr sourcechecked 2026-10-21 | 31,960 BTU (manual: 4.0 lb/hr input) sourcechecked 2026-10-21 |
| Heating area | Up to 2,800 sq ft sourcechecked 2026-10-21 | 1,500 sq ft sourcechecked 2026-10-21 |
| Efficiency | 80.5% sourcechecked 2026-10-21 | "HHV tested efficiency > 75%" sourcechecked 2026-10-21 |
| Hopper | 55 lb sourcechecked 2026-10-21 | 40 lb ("burns for up to 24 hours") sourcechecked 2026-10-21 |
| List price | $2,299 (comparison page also shows $2,799) sourcechecked 2026-10-21 | $1,299.99 sourcechecked 2026-10-21 |
| Advertised ÷ tested max | 1.00× | 1.44× |
| Tested BTU/hr per advertised sq ft | 14.5 | 14.8 |
Where They Differ
Output. The HP22’s tested maximum is 40,689 BTU/hr, nearly twice the Serenity’s 22,266. ComfortBilt advertises the EPA figure directly. Castle advertises 31,960 BTU, which its manual ties to a 4.0 lb/hr feed rate, so it’s a heat input number.
Efficiency. 81% vs 70% HHV for the 12327. Over a season, that 11-point gap means roughly 14% fewer pellets for the same heat from the HP22. Try it in the fuel calculator.
Hopper. 55 lb vs 40 lb. Castle says the Serenity “burns for up to 24 hours” on a full hopper, which only holds at its lowest setting.
Emissions. Similar: 1.0 vs 1.1 g/hr.
Price. ComfortBilt’s HP22 resource center showed $2,299 and its comparison page $2,799 on the day we checked. Castle lists the Serenity at $1,299.99.
Who Each One Suits
The HP22 suits a buyer who wants a full-size pellet stove at a fair price with honest output figures. The Serenity suits a single room or supplemental zone; at its tested output it isn’t a whole-house heater for most homes, whatever the area rating says.
Common Questions
Will the Castle Serenity heat 1,500 sq ft?
Castle’s manual sizes at 35 BTU/hr per square foot for a post-1982 house. At that rate, 1,500 sq ft needs 52,500 BTU/hr, more than twice the Serenity’s EPA-tested maximum of 22,266. In a small, very tight space it can go further, but treat it as a zone heater.
Is the Serenity over 75% efficient?
Castle’s product page says “HHV tested efficiency > 75%” without naming a model number. The 12327 listing is 70% HHV. EPA also lists a newer Serenity (model 41278) at 78% HHV and 12,807 to 26,493 BTU/hr. Check which model you’re buying.
Does the HP22 really heat 2,800 sq ft?
Its 40,689 BTU/hr maximum works out to about 14.5 BTU/hr per square foot over 2,800 sq ft, which is generous. In most houses, plan on well under that area.
See the full stove table, the heating and fuel calculator or other comparisons.