Musty smell when the AC starts
Drain pan and coil biofilm, not “the ducts are filthy, buy cleaning.”
If it only smells for 30 seconds at startup, start with the drain and coil — not a whole-home duct package.
East Bay cooling seasons are long. A dirty condenser or clogged drain in July is usually last spring’s skipped tune-up.
If the search that brought you here was “musty smell AC,” start with a test, not a replacement pitch.
Otter Basic is $250/unit; Otter-Pro is $350/unit. We inspect coils, electrical, drains, filters, and safety controls — and tell you what can wait.
On this call we confirm the symptom you described — musty smell when the ac starts — before we open a price book.
You approve any repair after the findings are written down. Diagnostic visits are a flat $69. New installation estimates are free in-home with a load calculation — not a number invented from square footage on Zillow.
A “cleaning” that is really a duct-cleaning add-on should be justified by actual debris, not a script.
A company that skips testing on musty smell AC will skip it on the next call too. We would rather lose a job than install the wrong thing.
Related service page on this site: air conditioner repair. The article you are reading is the explanation; that page is how to book the work.
OTTER HVAC is based at 2939 Santos Ln, Walnut Creek. Pleasant Hill, Berkeley, and Berkeley are regular routes, along with the rest of our listed East Bay cities. Hours are 7am–5pm, seven days a week. We do not advertise 24/7 because we do not staff a night shift.
Inland heat (Pleasanton, Livermore, Concord) and marine air (Alameda, Daly City) are different loads. A note written for Pleasant Hill is not automatically right for a fog-belt house. We treat them that way.
Category on this guide: Cooling. Primary search phrase: musty smell AC.
Call (650) 900-0440 or book online. Tell us the city, the symptom in one sentence, and the brand if you know it. If we have a window today, we will say so. If we do not, we will say that too.
Technicians are EPA 608, OSHA, and NATE certified. Public reviews average 5.0 stars across roughly 146 Google and 151 Yelp reviews. That does not replace a test on your unit.
Related service: Air Conditioner Repair. Book a $69 diagnostic or a free install estimate. Hours: 7:00am–5:00pm, seven days a week. Shop: 2939 Santos Ln, Walnut Creek, CA 94597.
Related: All HVAC guides · Air Conditioner Repair · Pricing and $69 diagnostic · Contact OTTER HVAC
Frequently asked questions
What do you test on a musty smell AC visit?
Otter Basic is $250/unit; Otter-Pro is $350/unit. We inspect coils, electrical, drains, filters, and safety controls — and tell you what can wait. The visit is a flat $69. Repair work starts only after you approve the written findings.
Will you quote musty smell AC from a photo?
No. We do not price musty smell AC from a driveway photo. $69 diagnostic, then a quote — or a free in-home install estimate if replacement is the honest path.
Do you handle this in Pleasant Hill and Berkeley?
Yes. We run Pleasant Hill, Berkeley, and the rest of our East Bay list from 2939 Santos Ln, Walnut Creek. Hours are 7am–5pm every day — not 24/7. Call (650) 900-0440.
Explore related pages
References and credentials
- U.S. DOE Energy Saver
- EPA Section 608
- EPA Section 608 refrigerant certification
- U.S. Department of Energy — Energy Saver
Authority sources: U.S. DOE Energy Saver · EPA Section 608