What to expect with new furnace installation
Installing a new furnace is a job for a licensed HVAC contractor. The time and cost can vary based on the type of furnace, where it is in your home, and whether any related work is needed. If you’re replacing an older model with a new high-efficiency furnace, there could be rebates or tax credits available that help offset the final cost.
Most new furnaces can be installed in one day. Here’s what to expect from the process, how long it typically takes, and what can affect the final price.
What’s involved in furnace installation?
Many of the key steps happen before installation day, during your quote and home assessment.
Home & furnace assessment:
Your installer will determine the right furnace size and capacity to heat your home efficiently and evenly.
Additional equipment options:
If you’re adding a new thermostat, air purifier, or humidifier, your installer will include them in the project scope.
Ductwork, gas & electrical:
The HVAC technician will evaluate your home’s gas lines, venting, ductwork, and electrical system to make sure they’re compatible with your new furnace, and let you know if any upgrades are needed.
Furnace installation day
Here’s how a typical furnace installation goes:
- Preparation: The installer clears the area so they have room to work.
- Old furnace removal: They’ll disconnect the existing furnace from the gas line, vent ducting, and wiring, then haul it away for proper disposal.
- System modifications: If necessary, they’ll make adjustments to gas lines, venting, electrical connections, and/or ductwork before connecting the new unit.
- New furnace setup: The new furnace is brought in, connected, and integrated with your thermostat.
- Testing and calibration: The entire system is tested for performance and safety by checking airflow, temperature rise, combustion, venting, gas pressure, CO levels, and thermostat response.
- Final walkthrough: Your installer will show you how to operate your new system, change filters, and handle basic maintenance. You’ll receive documentation for your warranty and records.
Factors that can increase furnace installation time or cost
There are certain conditions that can extend the timeline or increase labor costs:
- Major changes to ductwork, gas lines, or electrical
- Installing accessories like a whole-home humidifier or air purification system
- A difficult installation area (crawl space, cramped attic, etc.)
- Complex layouts requiring longer vent runs or other modifications
- New vent system, such as changing from an 80% (standard efficiency) vent system to a 90% (high-efficiency) PVC vent system.
- Projects switching fuel types
How to help your furnace installation go smoothly
Being prepared can make installation day easier for both you and your furnace installer:
- Double-check your installation paperwork for accuracy as soon as you receive it, and contact your installer if anything seems off or unclear.
- Clear the installation area before they arrive by moving any furniture, boxes, or other items blocking access to your furnace, electrical panel, or thermostat.
- Keep children and pets away from the work area.
- Expect a temporary gas and power shutoff: charge your devices and plan meals accordingly.
- Plan on being available during the installation in case questions come up.
How the Navien NPF hydro-furnace simplifies installation
Navien’s NPF hydro-furnace is designed to make installation faster and easier, keeping time and labor costs to a minimum.
- Flexible orientation that suits your space with horizontal and upflow models
- Left- or right-side convertible condensate trap, return air, and electrical hookups
- Works with single- or two-stage thermostats, and modern smart thermostats
- Seamless integration with indoor air quality (IAQ) systems
- Standard 2” venting compatible with schedule 40 PVC, CPVC, and polypropylene
- Setup Wizard in user-friendly EZNav™ control panel for quick configuration
- Factory-supplied NG/LP and high altitude conversion kits (up to 10,000 ft)
Learn more about how the Navien NPF hydro-furnace combines innovative design, efficiency, and flexibility for modern homes.
Furnace Installation FAQ
Get answers to the most common homeowner questions about furnace replacement.
Can you install a new furnace yourself?
No. Furnace installation must be done by a licensed HVAC professional for safety and compliance with local codes. DIY installation will void your warranty and may create safety hazards.
What’s the average cost of a furnace installation?
Furnace installation costs vary widely by region, furnace type, and the amount of work required. Labor typically makes up a significant portion of the final cost. To understand the average cost in your area, you need to compare quotes from qualified local installers.
What’s the average lifespan of a new furnace?
Most modern furnaces will last 15-20 years with proper maintenance.
Can you write off the cost of new furnace installation?
In some cases, replacing your furnace with a new high-efficiency model can qualify you for a federal tax credit, which is not the same as a tax deduction (“writing it off”). Some utility companies offer rebates for new furnace installations, but it varies by region. Find residential furnace rebates in your area.
When’s the best time of year to buy a new furnace?
The best time to buy a new furnace is before you need it, ideally before winter. Planning ahead helps you avoid an emergency furnace replacement! Demand tends to be lower in spring and fall, which could mean more flexibility in scheduling. If you’re counting on a tax credit for your new furnace, make sure you know the exact requirements and installation deadline.
Is it cheaper to replace the furnace and AC at the same time?
If your furnace and AC are both aging out, replacing them at the same time can reduce installation costs. Matched systems are designed to work together for optimal comfort and efficiency. Since the furnace and AC or heat pump, in a dual fuel installation, work together with the furnace moving the air in both modes, it might make sense to upgrade that component as well, to get the best performance out of your HVAC system.
Thinking about upgrading your furnace?
A new high-efficiency system can improve comfort, reduce noise, and save on monthly heating costs. The NPF hydro-furnace combines advanced technology with a compact, installer-friendly design—making it a smart choice for your next upgrade.
Where to find a qualified installer
Navien doesn’t provide installation services directly, but you can use our installer finder tool to connect with trained professionals in your area who are qualified to install Navien HVAC equipment.
If you’re still considering which type of new furnace to get, learn how variable capacity furnaces compare to single and two-stage models.
