Boilers
ENERGY STAR certified residential boilers, with AFUE efficiency, fuel type and hot water integration.
642 models · 51 brands
- Best
- 97%
- Median
- 95%
- Worst
- 87%
AFUE across 642 models that report it.
Residential boilers are rated by AFUE, the same metric as furnaces. Condensing boilers achieve AFUE above 90% by recovering heat from exhaust gases that non-condensing models waste. They require a condensate drain and acid-resistant venting, but the energy savings typically pay back the installation difference in 3–7 years.
Boilers heat water (or steam) that circulates through radiators, baseboard convectors, or radiant floor tubing. Radiant floor systems operate at lower water temperatures, which lets condensing boilers run in their most efficient range more of the time.
Most efficient
Ranked by AFUE, an efficiency ratio that does not scale with size.
| Model | Brand | AFUE |
|---|---|---|
| Accel CS EK1C 90 | Energy Kinetics | 97% |
| ASPN-085 | Burnham by U.S. Boiler | 96% |
| ASPN-110 | Burnham by U.S. Boiler | 96% |
| Accel CS EK1C 120 | Energy Kinetics | 96% |
| EFTU-85WBN | HTP | 96% |
| ELU-85WBN | HTP | 96% |
| SFB 99* | IBC Technologies | 96% |
| SFC 99* | IBC Technologies | 96% |