San José, by era rather than by map
Pre-war and early post-war — Naglee Park, the Rose Garden, downtown, older Willow Glen. Wall furnaces, floor furnaces, occasionally no cooling at all beyond a window unit. The interesting question here is rarely "repair or replace the furnace" but "what would replacing it with something ducted or ductless actually involve".
The great tracts, 1955–1980 — Cambrian, Blossom Valley, Berryessa, parts of Evergreen and Almaden. Forced air with the furnace in a hall closet or the garage, ducts in the attic or under the slab, and equipment that is now on its second or third replacement. Most of the repair-or-replace conversations on this site are these houses.
1985 onward — Silver Creek, Santa Teresa, later Almaden and Evergreen phases, North San José infill. Larger systems, sometimes two, and the failures are components rather than the system itself.
Inland neighborhoods run hotter than the numbers suggest: Almaden, Evergreen and Silver Creek regularly sit several degrees above downtown on a summer afternoon, and a system sized for a coastal-side house will not hold there.
Towns nearby
Campbell · Santa Clara · Sunnyvale · Cupertino · Saratoga · Los Gatos · Milpitas
The energy standards are the state's and do not vary between them. What varies is the paperwork: each town runs its own mechanical permit desk, prices it off its own schedule, and has its own waiting time for an inspector in August.
Addresses the city does not answer for
Several pockets carry San José mail while sitting outside the city limits — Burbank, the Cambrian Park pocket, Fruitdale, slices of East Foothills and Alum Rock. For a changeout at one of those addresses, the County of Santa Clara issues the permit and sends the inspector, on its own fee schedule and its own timetable. Neither the mailing address nor the neighbors settle which side of the line a parcel is on; the County publishes a Property Explorer that does, and two minutes with it beats discovering the answer when an inspector declines the job.
What this list is, and is not
It is the set of addresses whose rules an estimate here is checked against: the right permit desk for a changeout, and the rebate programs your account actually qualifies for — a question of which utility bills you, not of which street you live on. It is not a branch network. Everything here happens by photograph and in writing, and nothing about this business is walk-in.
Jurisdictional statements above come from published guidance of the County of Santa Clara and the City of San José. Annexation moves these lines from time to time; confirm your own parcel rather than trusting a neighbor's answer.