Olympia and Thurston County jobs are outside our free 20-mile Sumner radius, so expect the $1.75/mi travel line on the quote — still often cheaper than waiting weeks for a farther tester. We run residential blower door tests for permit finals and performance checks, with clear ACH50 numbers you can hand to the building department. Book a Fri–Sat slot online and we’ll confirm travel before the deposit.
Ensure your home or business is energy-efficient and comfortable with our professional blower door testing services.
Providing third party blower door testing results for Washington State Energy Code (R402.4.1.2) air leakage testing compliance.


Trained on Retrotec equipment.

Precise and thorough testing.

Retrotec Equipment for accurate results.
Trust our trained staff to conduct thorough Blower Door tests to assess your building's air tightness and identify potential energy leaks.
Ensure your project meets energy code regulations with our approved third-party WA Energy Code testing services.
We can use our blower door and FLIR thermal camera to identify where leaks are coming through your building envelope.
Copyright © 2026 WA Blower Door - All Rights Reserved.
Our family: Dow Engineering, Build Sherpas. Same office in Sumner.
WA Blower Door, a tradename of Dow Engineering PLLC · 16202 64th St E Ste 117, Sumner, WA 98390 · (253) 802-8738
Dow Engineering PLLC