Ductwork Installation and Replacement Across Puget Sound

Ductwork is the part of a heating and cooling system homeowners never see and installers too often ignore. A perfectly sized furnace or heat pump connected to leaky, undersized, or badly designed ducts will still leave rooms cold, run up bills, and wear out early. The equipment can only deliver the air the ducts allow it to move.

In Puget Sound we see two duct problems constantly: original ducts in older homes that leak into crawlspaces and attics, and ducts that were sized for an old furnace and choke a new higher-airflow heat pump. Getting the ductwork right is what turns a good equipment upgrade into a comfortable house. This page covers new duct installation, replacement, and the airflow work that makes systems actually perform.

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What a ductwork installation includes

We design the duct system to the airflow your equipment needs, using duct sizing based on the required cubic feet per minute, not on whatever fit last time. That means correctly sized trunks and branches, properly placed supply and return registers, and enough return air so the blower is not starved.

The install covers fabricating and running the ducts, sealing every joint, insulating runs in unconditioned spaces, and balancing airflow across rooms so the far bedroom gets its share.

Duct design sized to your equipment's required airflow
New trunk lines, branch runs, and register placement
Sealing of all joints and seams to cut leakage
Insulation of duct runs in attics and crawlspaces
Adequate return air to prevent a starved blower
Airflow balancing across rooms and floors

When ductwork needs installing or replacing

New ducts are needed when you add central heating or cooling to a home that never had it, finish a basement or attic, or build an addition. Replacement makes sense when existing ducts leak badly, are undersized for a new system, or are damaged, moldy, or crushed in a crawlspace.

The most common trigger we see is a heat pump or high-efficiency furnace upgrade revealing that the old ducts cannot move the required air. Upgrading the equipment without addressing the ducts caps the benefit you paid for.

Signs to watch for

Some rooms never reach temperature no matter the thermostat setting
High bills paired with visible or audible duct leaks
A new furnace, AC, or heat pump underperforming the old one
Ducts in the crawlspace that are crushed, disconnected, or moldy
Whistling, rattling, or a strong pressure difference at registers
Dust problems tied to unsealed return-side leakage

What ductwork costs and what drives it

Ductwork pricing depends heavily on scope. Sealing and minor modifications are relatively modest. A full duct replacement or a from-scratch system for an unducted home is a larger project, driven mostly by the amount of duct, access, and how many rooms need runs.

We quote by the actual design and access conditions, not a per-register shortcut, because a crawlspace with headroom is a very different job from a tight attic.

What drives the range

New system versus repair or partial replacement
Total length and complexity of the duct layout
Access conditions in attics, crawlspaces, or finished areas
Material choice and insulation requirements
Number of rooms and registers being served

Permits and efficiency programs

Ductwork that is part of a mechanical system change is permitted in Washington jurisdictions, and we handle the permit and inspection. Duct sealing and design also matter for equipment rebates: some utility heat pump programs expect the duct system to support the new equipment's airflow, so getting the ducts right can be part of qualifying.

When we install ducts alongside a heat pump conversion, we coordinate the duct work so it supports the rebate-eligible system rather than undercutting it. We confirm what your utility program requires for the specific equipment.

See current utility rebates

How the install works

1
Same-day estimate and assessment
We inspect the existing ducts or the unducted space, measure the airflow needs, and give you a written estimate the same day.
2
Duct design
We size the trunks, branches, and returns to the required airflow and plan register locations for even distribution.
3
Permitting
Where the work is part of a mechanical change, we file the permit and schedule inspection.
4
Fabrication and installation
We fabricate and run the ducts, seal every joint, and insulate runs in unconditioned spaces.
5
Balancing and verification
We balance airflow room by room and confirm the system delivers the air the equipment was designed to move.

Ductwork we install is backed by our workmanship warranty covering the sealing, connections, and support. Because leaky ducts undermine equipment performance, we treat proper sealing as part of protecting the comfort and efficiency you paid for.

Ductwork Installation questions, answered

Why are some rooms in my house always cold?

Usually it is a duct problem: an undersized or leaky run to that room, poor register placement, or not enough return air. Adding equipment capacity will not fix it if the ducts cannot deliver the air. We diagnose the duct system rather than just turning up the thermostat.

Do I need new ducts with a new heat pump?

Sometimes. Heat pumps often move more air than the old furnace the ducts were sized for. If the existing ducts are too small or too leaky, the heat pump underperforms. We check the duct capacity during the estimate and tell you honestly if it needs work.

How much does duct leakage cost me?

Leaky ducts in crawlspaces and attics can waste a significant share of the conditioned air you pay to produce, since it leaks into spaces you are not trying to heat or cool. Sealing them is one of the higher-return improvements in many older Puget Sound homes.

Can you add ducts to a home that never had them?

Yes, though it depends on access. Where there is crawlspace or attic room to route trunks and branches, we can design a full system. Where duct routing would be too invasive, a ductless mini split is often the better path, and we will say so.

Do you seal ducts as part of the install?

Always. Sealing every joint and seam is not an upsell, it is basic to a duct system doing its job. Unsealed ducts waste energy and pull dust from crawlspaces into your air, so sealing is standard on our work.

Related services

We serve homeowners across eight Puget Sound counties, Everett to Puyallup. See our full service area.

Authorized dealer for all major brands

We repair all major brands, whether or not we installed the system.

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Call between 7 AM and 10 PM, any day of the week, and you talk to us, not an answering service. Same-day estimates, upfront ranges, and financing available.

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