This is one of the most common questions I get from homeowners in the Longview and Kelso area: ductless or traditional? Which one costs less? Which one makes more sense?

The honest answer is: it depends almost entirely on whether your home already has ductwork. That one variable drives the financial comparison more than anything else, including brand, efficiency rating, or system size. If you get that part right, the rest usually follows.

Let me walk through the actual numbers.

The question that changes everything

Before getting into price ranges, ask yourself this: does your home currently have a forced-air duct system?

If yes, the comparison is genuinely close. Both options involve installing equipment; the ducts are already there.

If no, the math shifts dramatically in favor of a ductless system. Adding ductwork to a finished home costs $2,400-$6,600 for the ductwork alone, before you buy any equipment. That cost stacks on top of whatever the furnace or heat pump costs. A ductless mini-split skips all of that.

I’ll come back to this with real scenarios at the end. First, the numbers.

What ductless mini-splits cost to install

These are installed costs, meaning equipment plus labor, based on national pricing data. Longview and Kelso are not high-cost markets like Seattle or Portland, so actual quotes here tend to land toward the lower end of these ranges.

Single-zone system (one outdoor unit, one indoor head): $2,000-$5,500 installed. A single-zone is appropriate for one room, a garage, an addition, or a home where you need supplemental conditioning in one area.

Two-zone system (one outdoor unit, two indoor heads): $5,000-$9,000 installed.

Three-zone system (one outdoor unit, three indoor heads): $8,000-$13,000 or more installed.

Beyond three zones, costs scale roughly $1,500-$2,500 per additional indoor head depending on placement and line set routing complexity.

A few factors that push costs higher:

  • Larger BTU capacity (bigger home, bigger system)
  • Premium brands (Mitsubishi, Daikin, Bosch) cost more than budget brands and generally last longer
  • Electrical panel upgrades, if your panel doesn’t have capacity for the new dedicated circuit required. This adds $1,000-$3,000 for an electrician’s work and is a separate scope from the HVAC installation.
  • Complex installation routes, like running line sets through a finished attic or around structural elements

What traditional ducted systems cost to install

Again, these are installed costs including equipment and labor for a home with ductwork already in place.

Gas furnace plus central air conditioning: $8,000-$16,000 installed for a typical 1,500-2,500 sq ft home. The range is wide because it covers everything from a basic 80% efficiency furnace with a standard AC unit to a high-efficiency 96% AFUE furnace with a premium air conditioner. Replacing both at the same time usually saves $1,000-$2,000 compared to doing them separately.

Ducted heat pump with air handler: $8,000-$12,000 installed for a home that already has ductwork. High-efficiency models push toward the higher end.

Adding new ductwork to a home without it: $2,400-$6,600 for the ductwork alone. Add this to either of the above costs to get your real total for a duct-free home. A full ducted system installed in a home with no existing ducts can easily run $13,000-$22,000 or more.

I want to be clear about what that ductwork cost means. Cutting through finished walls, running sheet metal through attics and crawlspaces, and putting it all back together in a house that was never designed for it is labor-intensive. The $2,400-$6,600 estimate assumes reasonable access. A difficult layout with a finished attic and tight crawlspace can push that number higher.

Operating costs: how does efficiency translate to your bill

Cowlitz PUD’s residential electricity rate is approximately 9 cents per kilowatt-hour as of early 2026. This is well below the national average (around 16 cents/kWh) and one of the lowest rates in the country. Cowlitz County gets most of its power through the Bonneville Power Administration’s hydroelectric system, which is why rates are so favorable here.

Low electricity rates make heat pump technology more attractive compared to natural gas, because the economic case for heat pumps improves as electricity gets cheaper relative to gas.

Mini-splits are more efficient than ducted systems for two reasons. First, no duct losses. Ducts running through unconditioned attics and crawlspaces lose 20-30% of conditioned air through leaks and thermal transfer before that air ever reaches a room. Mini-splits deliver conditioned air directly to the space. Second, inverter-driven variable-speed compressors are inherently more efficient than single-stage compressors that cycle on and off.

In terms of rated efficiency: quality ductless mini-splits typically hit 18-28+ SEER2 for cooling and 10-13 HSPF2 for heating. Top ducted systems reach about 15-24 SEER2 and 8.1-12 HSPF2.

I want to be honest with you here: I don’t have a reliable annual dollar savings figure specific to Kelso/Longview that I’d feel comfortable putting in writing. Actual savings depend heavily on your home’s size, insulation quality, usage patterns, and what you’re replacing. The efficiency advantage is real, but the specific dollar amount I’d give you for your home would require a Manual J load calculation and knowledge of your actual usage, not a blog post estimate. Get quotes from local contractors that include projected operating costs based on your specific situation.

If you currently heat with gas, I’d also encourage you to call Cascade Natural Gas (which serves most of the Longview area) for their current residential rates. Gas-versus-electric comparisons require knowing the actual price of each fuel in your market right now.

Rebates and incentives as of early 2026

This is an area where the picture has changed recently and will likely keep changing, so I’ll tell you what I know and flag what to verify.

Washington State HEAR Program (income-qualified): The state’s Home Electrification and Appliance Rebate program provides point-of-sale rebates on heat pump installations, including ductless mini-splits. If your household income is below 80% of the area median income, the rebate can cover up to 100% of project cost, capped at $8,000. Between 80% and 150% AMI, it covers up to 50% of project cost. Above 150% AMI, this program is not available to you. The rebate comes off your invoice directly, not as a tax credit. The Washington State Department of Commerce administers this program.

Federal 25C tax credit: This credit provided 30% of installed cost, up to $2,000 per year, for qualifying heat pump installations. It expired December 31, 2025. Homeowners who had qualifying systems installed before that date can still claim the credit on their 2025 federal tax return. Whether Congress will extend or replace it for 2026 and beyond is unknown as of this writing. Don’t assume it applies to new 2026 installations without checking current IRS guidance or speaking with a tax professional.

Cowlitz PUD rebate: If Cowlitz PUD is your electric utility, they offer a rebate on ductless heat pump installations. The current rebate is $900 per unit. Pre-authorization is required before the equipment is removed or installed, so call them before scheduling the work, not after. Contact: (360) 501-9514 or [email protected]. Note that Cowlitz PUD has adjusted this rebate amount over the past couple of years, so confirm the current figure directly with them.

Pacific Power: If Pacific Power is your electric utility, their Wattsmart Homes program offers up to $1,800 cash back on ductless heat pump installations. Pre-approval is required and there are eligibility restrictions, including that the rebate is not available if you’re replacing an existing heat pump system. Contact Pacific Power directly to confirm current program terms.

Most of Cowlitz County is served by Cowlitz PUD, but some areas are Pacific Power territory. Check your electric bill to confirm which utility serves your address, and contact them before scheduling any work so you don’t lose rebate eligibility.

Lifespan: the long game

Mini-splits outlast traditional central HVAC systems by a meaningful margin. A well-maintained ductless system typically lasts 20-30 years. Traditional ducted systems, both furnaces and heat pumps, typically run 15-20 years.

The practical implication over a 20-year horizon: a homeowner with a traditional system may face one full replacement cycle that a mini-split owner avoids. That’s another $8,000-$16,000 equipment and installation cost that doesn’t show up in the upfront comparison but matters for true total cost of ownership.

This isn’t a guarantee. Maintenance matters. A well-serviced traditional system lasts longer than a neglected mini-split. But the rated lifespan difference is real and worth accounting for when you’re comparing options.

Two real scenarios

Let me put these numbers together in two common situations I see regularly.

Scenario A: Home with existing ductwork, replacing a 15-year-old gas furnace and AC.

This homeowner has functional ducts in place. The question is whether to replace like-for-like (gas furnace + central AC) or switch to a ductless system.

Traditional route: $10,000-$14,000 installed for a quality gas furnace and central air conditioner. If they choose a ducted heat pump instead, the range is similar at $8,000-$12,000.

Ductless route: A multi-zone system covering the main living areas might run $8,000-$13,000 installed. After the Cowlitz PUD rebate ($900 per unit), the effective cost drops. If the homeowner qualifies for the HEAR program, the savings go further.

In this scenario, ductless and traditional are genuinely competitive on upfront cost. The choice comes down to preference for zone control, long-term efficiency, and whether the existing ducts are in good shape or leaking significantly.

Scenario B: Older home with electric baseboard heat and no ductwork.

This is very common in southwest Washington. These homes were built before central forced-air was the default, and baseboard heaters are expensive to run.

Traditional route: Adding ductwork ($2,400-$6,600) plus the central system ($10,000-$16,000 for gas furnace and AC, or $8,000-$12,000 for a ducted heat pump). Total: $13,000-$22,000+ for equipment and ductwork combined, plus the disruption of cutting through finished walls and ceilings.

Ductless route: One to three mini-split zones covering the main living areas and bedrooms, $3,000-$9,000 installed depending on how many zones. Cowlitz PUD rebate applies.

In this scenario, ductless wins clearly on upfront cost, installation invasiveness, and operating efficiency.

What I actually recommend

For homes without ductwork: a mini-split is almost always the right financial choice, and it’s also the more efficient system. The comparison isn’t close once you add ductwork costs to the traditional option.

For homes with existing ductwork and a failing central system: get quotes for both and compare them honestly. The gap is smaller than most people expect, and either option can make sense depending on your priorities. If zone control matters to you, or if your ducts are poorly sealed or run through unconditioned spaces, mini-splits look better. If you want a single system that serves the whole house uniformly and your ducts are in reasonable shape, replacing the central system may make more sense.

For a garage, shop, addition, or room that needs independent conditioning: always a mini-split. There’s no practical alternative.

If you want to know what I’d recommend for your specific home, the best thing is to have me take a look. I can give you an honest assessment and quotes for whatever options make sense for your situation, without pushing you toward one or the other.

Call me at (360) 749-5441 or get a free quote.