Los Angeles / Altadena
Altadena is about 20 miles from the Census center point for Los Angeles in a straight line and covers 8.465 square miles of land (Census 2024 Gazetteer internal points and land area, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/, checked 2026-10-19).
Altadena has 41,705 residents (give or take 2,203) (ACS 2020-2024 5-year, table B01003, https://data.census.gov/table/ACSDT5Y2024.B01003?g=160XX00US0601290, checked 2026-10-19), about 4,927 people per square mile.
The quote form takes a ZIP code; for Altadena that is 91001 (Census 2020 ZCTA to county subdivision and ZCTA to place relationship files, ZIP areas at least 20% inside the town, https://www2.census.gov/geo/docs/maps-data/data/rel2020/zcta520/tab20_zcta520_cousub20_natl.txt and https://www2.census.gov/geo/docs/maps-data/data/rel2020/zcta520/tab20_zcta520_place20_natl.txt, checked 2026-10-19).
4,927 people per square mile puts Altadena in suburban density, where the outdoor unit usually sits in a side yard and the noise is not an issue for neighbors.
Of the 15,092 occupied homes in Altadena, 76% heat with natural gas, 0% with heating oil, 21% with electricity and 0% with propane (ACS 2020-2024 5-year, table B25040, https://data.census.gov/table/ACSDT5Y2024.B25040?g=160XX00US0601290, checked 2026-10-19).
Altadena has about the Los Angeles County oil share of 0% and 8 points less electric heat than the county's 29% (ACS 2020-2024 5-year, table B25040, https://data.census.gov/table/ACSDT5Y2024.B25040?g=050XX00US06037, checked 2026-10-19).
Gas heats 76% of Altadena against electricity at 21%, so most quotes here are a partial-home system that carries the shoulder seasons and the summer while the gas furnace handles the coldest nights, or a whole-home system when the house is ready for it.
The median Altadena home was built in 1946 (ACS 2020-2024 5-year, table B25035, https://data.census.gov/table/ACSDT5Y2024.B25035?g=160XX00US0601290, checked 2026-10-19) and the median home has 5.7 rooms (ACS 2020-2024 5-year, table B25018, https://data.census.gov/table/ACSDT5Y2024.B25018?g=160XX00US0601290, checked 2026-10-19).
Altadena has 15,815 housing units, 37% built before 1940 and 88% before 1980, with 6% built in 2000 or later (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=160XX00US0601290, checked 2026-10-19).
Altadena has 23 points more pre-1940 homes than Los Angeles County as a whole (14%) and 6 points fewer homes built after 2000 than the county's 12% (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=050XX00US06037, checked 2026-10-19). An older stock means more insulation upgrades before the heat pump goes in.
37% of Altadena homes were built before 1940 and 88% before 1980 (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=160XX00US0601290, checked 2026-10-19), so insulation is the first sizing question: an older home leaks more heat per square foot, and the installer runs a room-by-room heat-loss calculation to size the system for what the walls and windows actually hold in, not just the floor plan.
87% of Altadena homes are single-family detached, 4% are in two- to four-unit buildings and 3% are in buildings of five or more units (ACS 2020-2024 5-year, table B25024, https://data.census.gov/table/ACSDT5Y2024.B25024?g=160XX00US0601290, checked 2026-10-19).
With 87% detached houses and 4% in small multi-family buildings, a Altadena quote is usually one or two outdoor units with ducted or ductless heads sized room by room. With 23% of Altadena homes rented (ACS 2020-2024 5-year, table B25003, https://data.census.gov/table/ACSDT5Y2024.B25003?g=160XX00US0601290, checked 2026-10-19), the landlord signs the quote in many of them.
Altadena has 40 points more detached houses than Los Angeles County overall (47%) and 33 points fewer five-plus-unit buildings than the county's 36% (ACS 2020-2024 5-year, table B25024, https://data.census.gov/table/ACSDT5Y2024.B25024?g=050XX00US06037, checked 2026-10-19).
No electric utility is on file for Altadena on this door yet, so this page does not name one; the name on the bill decides which rebate path applies.
LADWP Consumer Rebate Program heat pump HVAC, run by LADWP, is a live program for California addresses and publishes its terms without one headline figure (registry row 24 verified 2026-10-14, https://www.ladwp.com/residential-services/assistance-programs/consumer-rebate-program, checked 2026-10-16); confirm eligibility for the Altadena address before counting it. With 21% of Altadena homes already on electric heat and 76% on gas, oil or propane, the row that applies depends on the name on the electric bill and the fuel coming out.
Median household income in Altadena is $128,720 (ACS 2020-2024 5-year, table B19013, https://data.census.gov/table/ACSDT5Y2024.B19013?g=160XX00US0601290, checked 2026-10-19); many state and utility heat pump rebate programs set higher incentive tiers for income-qualifying households, so the household income on the application, not the town median, decides which level applies.
Heating design temperature: 14F. Source: ENERGY STAR Design Temperature Limit Reference Guide (2019 Edition), Los Angeles County row, 99% heating, PDF pages 11 to 13 of 141 (Revised 11/11/2020), https://www.energystar.gov/sites/default/files/Design%20Temperature%20Limit%20Reference%20Guide%20(2019%20Ed)%20-%20ENERGY%20STAR%20Single-Family%20New%20Homes_Rev11.pdf, fetched 2026-10-19, 99%.
That 14F figure is the Los Angeles County cold-day number a Altadena heat pump is sized against, so ask the installer to show the system's heating output at 14F, not at the milder rating-label temperature.
Ask whether the quote is whole-home or partial-home, because with 76% of Altadena on gas and 21% already electric the two paths carry different rebate figures and different sizing.
Ask for the heat-loss calculation room by room; a Altadena house from before 1940 (37% of the 15,815 units) rarely matches a square-footage rule of thumb.
The form on this page is the follow-up for Altadena. The public number is the number the contractor quotes from.
No local contractor is named on this door for Altadena yet. A request from this page goes to the first licensed shop that takes the door.