NTI GF200 Combi Furnace 

What do you get when you combine hydronic heat, a tankless water heater, and a forced air furnace? Read this to find out. 

A graphical rendering of the NTI GF200 Combi Furnace | Construction Pro Tips

I’m a huge fan of the new ultra-efficient NTI Hydronic Air handler, which combines hydronic heat, a tankless water heater, and a forced air furnace. This is not an ad, and I don’t work for NTI. It’s just that as a HVAC contractor I’ve been waiting for this technology for a long time and am excited to finally get the chance to work with it. In the world of forced air systems (furnaces) currently they have reached their optimum efficiencies. Concerns about limited mechanical room space, electrical efficiency still are still prominent. In my opinion, this “all in one use” approach is the new frontier.

What is it?

The NTI GF200 is basically a Navien NPE 240 water heater, which includes a fan blower assembly, hydronic coils and supporting components all wrapped by the NTI shell. The tankless water heater not only supplies hydronic and potable hot water to the house, it also circulates through hydronic coils and provides BTU’s for the forced air furnace. The NTI GF200 delivers a 97.1% AFUE Efficiency and 96% TPF. Install a standard A-coil refrigeration unit on top of the NTI and you now have air conditioning as well.


While it has a slightly bigger body than the standard furnace, the NTI GF2000 maintains a short height which all of us HVAC contractors enjoy, because it allows for an easy retrofit into existing forced air systems. With no separate hot water source needed, there are real space savings involved.

One size fits all

The operating BTU output range is from 20KBTU to 80KBTU. That’s right, one size fits all within this category. A modulating gas valve, exceptional turndown ratios, 10 stages of modulation, DC-ECM motor/shaftless blower wheel, and CFM modifications allow you to quickly tune the NTI GF2000 in the field to your appropriate calc loads.

What is a DC ECM shaftless blower motor?

Imagine removing a standard blower motor and shaft assembly from the center of the blower wheel and replace it with magnetic disc to turn the blower. The DEC Star ECM Blower automatically adjusts to overcome static pressure to maintain CFM. A shaftless blower system reduces air flow restrictions and improves efficiency.


We find the NTI GF200 a great fit for work on high performance energy houses: Passive House, Net Zero and Energy Star. That’s because the modulation range allows it to operate down to 20KBTU’s. Many of these houses have such small heat calc loads that most standard HVAC equipment is too big. Of course, the NTI GF-200 will work great for any household seeking a retro-fit for replacement of existing furnace and water heater. The NTI GF200 is available throughout North America. This unit has lived up to our expectations and all our customers have been thrilled with the results. For more information check out this video:

Meet the expert:

Dustin Denison is Principal of Applied Energy Innovations (AEI) and a 25 year veteran in the HVAC mechanical trades (Commercial/Industrial/Residential). AEI provides services that include solar, insulation, construction, and HVAC. Dustin holds 4 Master and has over 30 professional licenses and certifications. With a specialty niche in high performance homes/buildings, Dustin has designed and installed systems with demanding performance expectations by utilizing cutting edge technologies, products, and services in the HVAC field.