Charleston / Charleston
Charleston has 154,338 residents (give or take 200) (ACS 2020-2024 5-year, table B01003, https://data.census.gov/table/ACSDT5Y2024.B01003?g=160XX00US4513330, checked 2026-10-19), about 1,339 people per square mile.
Charleston is the city this door is named for; it covers 115.246 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).
The quote form takes a ZIP code; for Charleston that is 29401, 29403, 29407, 29409, 29412, 29414, 29424, 29425 and 1 more (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).
Median household income in Charleston is $92,414 (ACS 2020-2024 5-year, table B19013, https://data.census.gov/table/ACSDT5Y2024.B19013?g=160XX00US4513330, 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.
48% of Charleston homes are single-family detached, 9% are in two- to four-unit buildings and 35% are in buildings of five or more units (ACS 2020-2024 5-year, table B25024, https://data.census.gov/table/ACSDT5Y2024.B25024?g=160XX00US4513330, checked 2026-10-19).
44% of Charleston homes are rented (ACS 2020-2024 5-year, table B25003, https://data.census.gov/table/ACSDT5Y2024.B25003?g=160XX00US4513330, checked 2026-10-19), so beside the 48% detached houses there is a real share of jobs where the landlord, not the resident, signs the quote.
Charleston has 10 points fewer detached houses than Charleston County overall (58%) and 12 points more five-plus-unit buildings than the county's 23% (ACS 2020-2024 5-year, table B25024, https://data.census.gov/table/ACSDT5Y2024.B25024?g=050XX00US45019, checked 2026-10-19).
44% of Charleston homes are rented (ACS 2020-2024 5-year, table B25003, https://data.census.gov/table/ACSDT5Y2024.B25003?g=160XX00US4513330, checked 2026-10-19), so the market splits between resident-led jobs where the occupant picks the system and landlord-led jobs where they do not, and the rebate paperwork differs.
Of the 68,027 occupied homes in Charleston, 25% heat with natural gas, 0% with heating oil, 73% with electricity and 1% with propane (ACS 2020-2024 5-year, table B25040, https://data.census.gov/table/ACSDT5Y2024.B25040?g=160XX00US4513330, checked 2026-10-19).
Electricity already heats 73% of Charleston homes, ahead of gas at 25%, and a home on electric baseboard sees the biggest bill change from a heat pump because it replaces resistance heat one for one.
Charleston has about the Charleston County oil share of 0% and 3 points less electric heat than the county's 76% (ACS 2020-2024 5-year, table B25040, https://data.census.gov/table/ACSDT5Y2024.B25040?g=050XX00US45019, checked 2026-10-19).
No electric utility is on file for Charleston on this door yet, so this page does not name one; the name on the bill decides which rebate path applies.
Charleston has 77,417 housing units, 10% built before 1940 and 34% before 1980, with 45% built in 2000 or later (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=160XX00US4513330, checked 2026-10-19).
Charleston has 5 points more pre-1940 homes than Charleston County as a whole (5%) and 6 points more homes built after 2000 than the county's 39% (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=050XX00US45019, checked 2026-10-19). An older stock means more insulation upgrades before the heat pump goes in.
The median Charleston home was built in 1995 (ACS 2020-2024 5-year, table B25035, https://data.census.gov/table/ACSDT5Y2024.B25035?g=160XX00US4513330, checked 2026-10-19) and the median home has 5.3 rooms (ACS 2020-2024 5-year, table B25018, https://data.census.gov/table/ACSDT5Y2024.B25018?g=160XX00US4513330, checked 2026-10-19).
45% of Charleston housing was built in 2000 or later (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=160XX00US4513330, checked 2026-10-19), and homes that recent usually meet the insulation codes in place at the time, so a heat pump sized to the floor plan lands closer to the real load than it would in an older neighborhood.
Heating design temperature: 28F. Source: ENERGY STAR Design Temperature Limit Reference Guide (2019 Edition), Charleston County row, 99% heating, PDF pages 105 to 107 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 28F figure is the Charleston County cold-day number a Charleston heat pump is sized against, so ask the installer to show the system's heating output at 28F, not at the milder rating-label temperature.
Ask for the heat-loss calculation room by room; the median Charleston home has 5.3 rooms and was built around 1995, and the count of heads and the tonnage follow the rooms and the insulation, not the square footage.
The form on this page is the follow-up for Charleston. The public number is the number the contractor quotes from.
No local contractor is named on this door for Charleston yet. A request from this page goes to the first licensed shop that takes the door.