90+ Resolute™

Exceptional Energy Efficiency that sidewall vents or vents through your existing chimney without an expensive stainless steel liner.

Homeowners enjoy economical heat, plus virtually endless hot showers with lower energy costs. It's a non-condensing 90+ AFUE in gas and oil models, and goes beyond AFUE with low idle loss for better delivered efficiency. 90+ Resolute is ideal for fin tube baseboard, cast iron radiators, air handlers, and unit heaters, complementing its exceptional performance with high efficiency and nearly endless hot water.

Oil - Natural Gas - Propane
Residential Boiler


Non-Condensing Boiler

Our pressure vessel doesn’t suffer from the corrosive condensate that limits the life of many condensing boilers. Plus, there’s no condensate trap, neutralizer or drain required, which simplifies your installation and minimizes related service calls for years to come.

Beyond AFUE

AFUE does not accurately rate heat and hot water systems and misses significant areas of energy loss. There are tremendous opportunities to increase efficiency over AFUE estimates alone. The Department of Energy’s Brookhaven National Labs study demonstrates our design as the top performing system, saving up to 38% over boilers from around the world. The 90+ Resolute improves on the highest real efficiency of all systems tested, delivering even better peak and annual efficiency.


  • Whisper Quiet
  • Endless Hot Showers
  • Built to Outlast and Outperform Cast Iron
  • Proudly Made in USA!
  • Industry leading efficiency
  • Exceptionally clean burning
  • Easily piped to multiple zones
  • Multi-fuel (easy to convert from oil to natural gas or propane)
  • 5 zone control, upgrade to 12 zones including hot water
  • ASME certified construction
  • Outside combustion air connection
  • Cuts up to 40% or more off the home heating bills
  • Gas protection alarm included with every gas systems
  • View More Benefits


Resolute Warranty OKEnergy Kinetics provides the best pressure vessel in the industry along with a lifetime limited warranty and a ten-year labor allowance for residential pressure vessels. This is backed by a track record of over 35 years of proven, industry leading pressure vessel longevity. Residential pressure vessels also offer a lifetime warranty transfer from the original owner to a new owner. The Digital Energy Manager carries a 5-year warranty and an extended protection plan for the life of your 90+ Resolute. Refer to the specific warranty for details.

Chimney or Sidewall Venting

90+ Resolute Versatile Venting90+ Resolute can vent with a polypropylene flexible chimney liner, or be sidewall vented for gas or oil systems. Both are excellent options instead of repairing an existing chimney or installing an expensive stainless steel chimney liner.  With 90+ Resolute’s unique combustion chamber, combined with a nearly 15-foot long flue passage, gases leave clean, and relatively cool. So they can be vented directly through-the-wall.