Navien Furnaces and AC Condensers: A Guide for Chicago-Area Homeowners
· 7 min read · Right Away Plumbing and HVAC
Thinking about replacing a furnace and outdoor AC unit together? Navien's current HVAC lineup includes gas furnaces, air-conditioning condensers and indoor coils. Understanding which part does which job makes an estimate easier to compare.
For homeowners in Des Plaines, Chicago and nearby suburbs, the useful question is how a proposed system fits the house: its heating demand, ductwork, installation space and cooling needs. A brand name alone cannot answer that.
Which Navien equipment does what?
| Equipment | Job | Key published detail |
|---|---|---|
| NPF Hydro-furnace | Gas-fired hydronic forced-air heating | 97% AFUE; 15–100% variable heating capacity |
| NDF gas furnace | Conventional condensing forced-air heating | 96% AFUE; two-stage heating |
| NAA outdoor condenser | Air conditioning | Inverter-driven variable capacity; selected matches up to 18 SEER2 |
| NAM cased coil | Indoor refrigerant coil | Must be selected for the approved equipment combination |
Table data comes from Navien's official NPF, NDF, NAA and NAM series pages, linked below. Ratings describe specific equipment or matched combinations; confirm the exact model and AHRI match in the proposal.
NPF hydro-furnace: water transfers the heat, ducts deliver it
The NPF burns gas to heat water inside the furnace, then transfers that heat through a hydronic coil to the air moving through your ducts. Navien lists a variable-speed blower and a heating range from 15% to 100% of capacity.
In plain words: it still delivers warm air through registers. The difference is how heat gets into that air. The NPF is not simply a radiator boiler, and the standard furnace should not be assumed to supply household hot water.
Source: Navien NPF series page.
NDF furnace: a different approach to gas heating
The NDF is Navien's conventional condensing gas furnace. Its two-stage burner provides lower and higher heating output, while a variable-speed blower moves air through the system. Navien lists 96% AFUE.
In plain words: the NDF and NPF are different furnace designs. Compare the actual models and installation requirements rather than treating the names as interchangeable.
Source: Navien NDF series page.
NAA condenser: the outdoor air-conditioning unit
Navien's NAA is a variable-capacity air conditioner using an inverter-driven compressor and R-454B refrigerant. Navien advertises up to 18 SEER2 for selected matched systems.
In plain words: this outdoor unit handles cooling. It works with an appropriate indoor coil and blower; it does not become a heat pump because the compressor changes speed. The exact installed combination determines the applicable rating.
Source: Navien NAA series page.
Why the indoor coil and equipment match matter
A replacement quote should identify the furnace, outdoor condenser and indoor coil by model. Navien identifies the NAM as its cased-coil line. Its NDF product page describes a system using an NDF furnace, NAA condenser and NAM coil; the NAA page also describes NPF pairings.
In plain words: buying an outdoor unit is only one part of the decision. Ask for the approved combination and its AHRI rating, not just a top efficiency number from a brochure.
Sources: Navien NAM series page and
What to review before replacing a furnace and condenser in Chicagoland
Ask these questions before approving an estimate:
- How was the home's heating and cooling load calculated?
- Can the supply and return ducts support the required airflow?
- What changes are needed to venting, combustion air or condensate drainage?
- Are the electrical supply, refrigerant lines and installation location suitable?
- Which thermostat and controls will operate the selected combination?
- What startup measurements and commissioning checks are included?
- What maintenance, registration and written warranty requirements apply?
Comparing two proposals
These questions help compare the scope of two proposals. A lower equipment price may leave out work that is needed to make the complete installation perform properly. Actual operating costs depend on the house, weather, utility rates, system selection and installation.
Do you need to replace both at once?
Ask for an assessment of the existing equipment before deciding. A failed furnace does not automatically prove that an otherwise serviceable outdoor unit must be replaced. Equally, keeping old equipment should not be assumed compatible with a new system. The condition of each component and the approved match should guide the recommendation.
If you are deciding between repair and replacement, start with our furnace repair page.
For replacement planning, see furnace installation.
Cooling replacement is covered on our AC installation page.
See all heating services.
See all cooling services.
Sources
Official Navien pages reviewed October 16, 2026:
Frequently asked questions
Are NPF and NDF the same furnace?
No. The NPF uses hydronic heat transfer to warm ducted air; the NDF is a conventional condensing gas furnace.
Is the NAA condenser a heat pump?
No. The NAA is Navien's air-conditioning series. Heating with an outdoor heat pump requires a different product and approved system configuration.
Will every NAA installation deliver 18 SEER2?
No. Navien's "up to" rating applies to selected matched combinations. Confirm the rating for the exact outdoor unit, indoor coil and furnace or air handler specified.
Can a new furnace fix rooms that stay cold?
It depends on the cause. Equipment selection should follow an evaluation of airflow, controls, ductwork and the home's heating demand.
Talk to Right Away
Right Away Plumbing & HVAC serves Des Plaines, Chicago and surrounding suburbs. Tell us what equipment you have now and what is not working so we can discuss the next step.
Des Plaines & suburbs: 847-550-3322. Chicago: 773-250-6060.
You can read more about our plumbing services, check the communities we serve, or start with plumbing in Des Plaines and Park Ridge. Planning a remodel or weighing a big replacement? Our consulting service is built for that conversation.
Service areas for this work include Des Plaines and Chicago. Questions about your building? Use our contact page.