Seattle / Mountlake Terrace
Mountlake Terrace has 23,104 residents (give or take 48) (ACS 2020-2024 5-year, table B01003, https://data.census.gov/table/ACSDT5Y2024.B01003?g=160XX00US5347490, checked 2026-10-19), about 5,696 people per square mile.
Mountlake Terrace is about 12 miles from the Census center point for Seattle in a straight line and covers 4.056 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 Mountlake Terrace that is 98043 (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).
5,696 people per square mile puts Mountlake Terrace in suburban density, where the outdoor unit usually sits in a side yard and the noise is not an issue for neighbors.
Of the 9,855 occupied homes in Mountlake Terrace, 32% heat with natural gas, 1% with heating oil, 64% with electricity and 2% with propane (ACS 2020-2024 5-year, table B25040, https://data.census.gov/table/ACSDT5Y2024.B25040?g=160XX00US5347490, checked 2026-10-19).
Electricity already heats 64% of Mountlake Terrace homes, ahead of gas at 32%, and a home on electric baseboard sees the biggest bill change from a heat pump because it replaces resistance heat one for one.
Mountlake Terrace has about the Snohomish County oil share of 1% and 11 points more electric heat than the county's 53% (ACS 2020-2024 5-year, table B25040, https://data.census.gov/table/ACSDT5Y2024.B25040?g=050XX00US53061, checked 2026-10-19).
Mountlake Terrace has 10,210 housing units, 0% built before 1940 and 60% before 1980, with 16% built in 2000 or later (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=160XX00US5347490, checked 2026-10-19).
Mountlake Terrace has 5 points fewer pre-1940 homes than Snohomish County as a whole (5%) and 16 points fewer homes built after 2000 than the county's 32% (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=050XX00US53061, checked 2026-10-19).
The median Mountlake Terrace home was built in 1973 (ACS 2020-2024 5-year, table B25035, https://data.census.gov/table/ACSDT5Y2024.B25035?g=160XX00US5347490, checked 2026-10-19) and the median home has 4.9 rooms (ACS 2020-2024 5-year, table B25018, https://data.census.gov/table/ACSDT5Y2024.B25018?g=160XX00US5347490, checked 2026-10-19).
51% of Mountlake Terrace homes are single-family detached, 6% are in two- to four-unit buildings and 37% are in buildings of five or more units (ACS 2020-2024 5-year, table B25024, https://data.census.gov/table/ACSDT5Y2024.B25024?g=160XX00US5347490, checked 2026-10-19).
43% of Mountlake Terrace homes are rented (ACS 2020-2024 5-year, table B25003, https://data.census.gov/table/ACSDT5Y2024.B25003?g=160XX00US5347490, checked 2026-10-19), so beside the 51% detached houses there is a real share of jobs where the landlord, not the resident, signs the quote.
Mountlake Terrace has 13 points fewer detached houses than Snohomish County overall (64%) and 16 points more five-plus-unit buildings than the county's 21% (ACS 2020-2024 5-year, table B25024, https://data.census.gov/table/ACSDT5Y2024.B25024?g=050XX00US53061, checked 2026-10-19).
43% of Mountlake Terrace homes are rented (ACS 2020-2024 5-year, table B25003, https://data.census.gov/table/ACSDT5Y2024.B25003?g=160XX00US5347490, 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.
60% of Mountlake Terrace homes were built before 1980 and only 16% in 2000 or later (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=160XX00US5347490, checked 2026-10-19), so most of the stock predates modern insulation codes; the installer's heat-loss calculation, not a square-footage rule, decides the tonnage.
No electric utility is on file for Mountlake Terrace on this door yet, so this page does not name one; the name on the bill decides which rebate path applies.
PSE heat pump rebates (electric resistance to ASHP conversion), run by Puget Sound Energy, is a live program for Washington addresses and covers qualifying equipment at $2,400 per system (registry row 14 verified 2026-10-14, https://www.pse.com/en/rebates/heating/electric-resistance-to-air-source-heat-pump-conversion-rebate, checked 2026-10-16); confirm eligibility for the Mountlake Terrace address before counting it. With 64% of Mountlake Terrace homes already on electric heat and 35% on gas, oil or propane, the row that applies depends on the name on the electric bill and the fuel coming out.
Seattle City Light heat pump instant discounts, run by Seattle City Light, is a live program for Washington addresses and lists a standard figure of $300 (registry row 47 verified 2026-10-16, https://seattle.gov/city-light/residential-services/home-energy-solutions/heating-and-cooling-your-home, checked 2026-10-16); confirm eligibility for the Mountlake Terrace address before counting it.
Seattle Clean Heat Program (oil to heat pump), run by City of Seattle Office of Sustainability and Environment, is a live program for Washington addresses and lists a standard figure of $2,000 (registry row 48 verified 2026-10-14, https://seattle.gov/environment/climate-change/buildings-and-energy/seattles-clean-heat-program, checked 2026-10-16); confirm eligibility for the Mountlake Terrace address before counting it.
Median household income in Mountlake Terrace is $107,687 (ACS 2020-2024 5-year, table B19013, https://data.census.gov/table/ACSDT5Y2024.B19013?g=160XX00US5347490, 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: 24F. Source: ENERGY STAR Design Temperature Limit Reference Guide (2019 Edition), Snohomish County row, 99% heating, PDF pages 133 to 135 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 24F figure is the Snohomish County cold-day number a Mountlake Terrace heat pump is sized against, so ask the installer to show the system's heating output at 24F, not at the milder rating-label temperature.
Ask for the heat-loss calculation room by room; the median Mountlake Terrace home has 4.9 rooms and was built around 1973, 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 Mountlake Terrace. The public number is the number the contractor quotes from.
No local contractor is named on this door for Mountlake Terrace yet. A request from this page goes to the first licensed shop that takes the door.