Top 7 HVAC companies in King, Washington

King County spans IECC zones 4C-6B with a dominant marine climate that produces 4,700 heating degree days against only 400 cooling degree days. Winter design temperature sits at 28°F and summer at 85°F. Installed costs appear high: one source gives a typical full-system price of $11,550 while another records an invoiced average of $20,490. Seven companies surface from public listings after Bayesian adjustment of their star ratings.

How to choose

Companies are ranked by a Bayesian-adjusted rating: a company's star rating is pulled toward the national mean until it has enough reviews to stand on its own, so a 5.0 from four customers does not outrank a 4.9 from two hundred. Small tie-breakers apply for a public website, for being listed as an HVAC specialist rather than a general contractor, and for published 24/7 availability. This is a shortlist built from public listing data, not a review of work performed.

The shortlist

RMR Heating and Cooling

RMR Heating and Cooling operates from 32721 NE 52nd St, Carnation, WA 98014 and lists (206) 798-5013. Its 31 reviews produced a raw rating of 5.0 that the ranking adjusted downward to 4.944 because the national mean sits at 4.764; the pull is modest given the review count. The firm appears as a general contractor with published 24/7 availability and maintains a public website. These numbers cannot reveal whether the same crew that earned the early reviews remains on site today.

Hollingworth Heating & Cooling

Hollingworth Heating & Cooling lists its address as 35310 SE Center St Ste 591, Snoqualmie, WA 98065 and can be reached at (425) 650-4191. Twenty-two reviews at a raw 5.0 yielded an adjusted score of 4.924 after downward movement toward 4.764. The listing shows a general contractor offering 24/7 service plus a website. The data leave open whether recent growth has changed response times or crew experience.

All Star Heating & A/C

All Star Heating & A/C is based at 4223 338th Pl SE, Fall City, WA 98024 and answers calls at (425) 222-7652. Its nine reviews produced a raw 5.0 adjusted to 4.878. The entry carries general-contractor status, 24/7 availability, and a website. Limited reviews mean the score still moves noticeably toward the mean; the figures give little indication of performance on larger commercial jobs.

ALPHA HEATING, AIR CONDITIONING, PLUMBER & ELECTRICIAN

ALPHA HEATING, AIR CONDITIONING, PLUMBER & ELECTRICIAN operates from 429 227th Ln NE, Sammamish, WA 98074 and lists (425) 800-0034. Six reviews at raw 5.0 produced an adjusted 4.863. The listing is a general contractor with 24/7 availability and a website. The small sample size creates a visible pull toward 4.764, and the numbers cannot speak to how the firm handles multi-trade coordination on complex sites.

OX HVAC Contractor Seattle LLC

OX HVAC Contractor Seattle LLC is located at 7718 S 118th St, Seattle, WA 98178 and can be reached at (253) 215-5625. Eleven reviews at raw 5.0 adjusted to 4.847. The entry shows general-contractor status and 24/7 availability but no website. The adjustment from 5.0 is smaller than for firms with fewer reviews, yet the data still leave open questions about long-term service records.

Redmond HVAC Services

Redmond HVAC Services lists 17228 NE 85th Pl, Redmond, WA 98052 and the number (425) 930-0761. Six reviews at raw 5.0 moved to 4.823 after adjustment. The listing is a general contractor with 24/7 availability and no website. The modest review count keeps the score closer to the mean than larger samples would, and the figures offer no view of actual completed projects.

Renton HVAC Repair Service

Renton HVAC Repair Service is at 4411 NE Sunset Blvd, Renton, WA 98059 and answers at (425) 358-6595. Five reviews at raw 5.0 produced an adjusted 4.798. The entry is a general contractor without 24/7 listing or website. With the smallest sample, the score sits nearest the national mean, and the data cannot indicate how the firm performs once a job moves beyond initial service calls.

Cost

Two independent sources diverge on installed prices. One places a typical full-system install at $11,550 inside a band of $10,400 to $12,700. The second reports an invoiced average of $20,490 with the upper quartile reaching $30,122. Labor is stated at $145 per hour. Permit fees range from $150 to $550 depending on the local authority. Both sources are cited because the spread itself signals market variability rather than a single reliable figure. Homeowners should obtain multiple written bids that itemize equipment, labor, and permit costs separately.

Licensing and permits

Washington State Department of Labor & Industries maintains statewide contractor registration. HVAC work falls under specialty licensing that requires a $15,000 surety bond for specialty contractors plus either $200,000 public liability and $50,000 property damage coverage or a $250,000 combined single limit. A workers’ compensation account is mandatory where applicable. L&I registration is statewide, yet residential HVAC permit issuance remains a local function administered by the applicable city or county building department. Manufactured-home furnace and heat-pump replacements require separate L&I permits. Homeowners can verify any firm at the public lookup located at https://secure.lni.wa.gov/verify/Results.aspx.

Incentives

Washington Home Energy Rebates administered by the Department of Commerce are approved for launch in late 2025, with heat-pump rebates up to $8,000. A sales-tax exemption applies to qualifying heat-pump equipment and labor. Utility programs, largely BPA-funded in public utility districts, offer $500–$2,000 rebates but require contractors from approved network lists. The 25C and 25D federal tax credits expired at the end of 2025; no residential federal HVAC credit exists in 2026. The 48E investment tax credit survives only for commercial or third-party-owned systems meeting construction or placed-in-service deadlines. Homeowners should therefore confirm whether their utility maintains an approved-contractor list before soliciting bids.

Climate

King County’s dominant 4C marine zone produces mild, damp winters and dry summers. Heating loads dominate at 4,700 degree days while cooling remains modest at 400 degree days. Winter design temperature is 28°F and summer 85°F. The engineering note highlights historically low central-AC saturation that is now rising after recent heat events. Equipment must therefore handle heating-dominant operation while providing reliable dehumidification in shoulder seasons. Proper sizing remains critical because oversizing reduces efficiency and comfort in the mild heating load. Heat-pump suitability is rated excellent for this climate.

Public data alone cannot confirm workmanship or current crew quality. Obtain multiple bids, verify current L&I status, and confirm utility-network eligibility before signing any contract.