Know your filter size before the smoke hits
Write it on the furnace door.
The 1am Target run during a wildfire is the wrong time to discover you need a 16x25x1, not a 20x20.
East Bay cooling seasons are long. A dirty condenser or clogged drain in July is usually last spring’s skipped tune-up.
Use this as a field guide to HVAC filter size, then book a visit if the house still misbehaves.
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.
We map HVAC filter size to the actual failed part or design limit. Age of the system is a data point, not the diagnosis.
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 HVAC filter size 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: maintenance. 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. Concord, Orinda, and San Ramon 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 Concord is not automatically right for a fog-belt house. We treat them that way.
Category on this guide: Maintenance. Primary search phrase: HVAC filter size.
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: HVAC Maintenance. 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 · HVAC Maintenance · Pricing and $69 diagnostic · Contact OTTER HVAC
Frequently asked questions
What do you test on a HVAC filter size 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 HVAC filter size from a photo?
No. We do not price HVAC filter size 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 Concord and Orinda?
Yes. We run Concord, Orinda, 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