Best Licensed HVAC Contractors in Diamond Bar, CA
30 HVAC contractors registered in Diamond Bar hold current CSLB licenses, verified against official records as of August 17, 2026. The 8 below are the top-ranked, ordered by years licensed.
- 2,674 active C-20 heating and air conditioning licenses in Los Angeles County; 30 registered in Diamond Bar
- California requires workers' compensation cover for C-20 licensees: 30 of Diamond Bar's 30 licenses (100.0%) carry a current policy with CSLB
- Median time licensed in Diamond Bar: 8 years
- Longest Diamond Bar licensure: since 1989
- 206 county licenses reach their expiration date within 90 days
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- Verified
- August 17, 2026
- Licensed since
- 1989
- Expires
- 2027-11-30
- Phone
- (909) 821-5040
- Verified
- August 17, 2026
- Licensed since
- 1991
- Expires
- 2027-03-31
- Phone
- (626) 239-8189
- Verified
- August 17, 2026
- Licensed since
- 1991
- Expires
- 2027-10-31
- Phone
- (909) 996-1474
- Verified
- August 17, 2026
- Licensed since
- 1993
- Expires
- 2027-04-30
- Phone
- (213) 798-4693
- Verified
- August 17, 2026
- Licensed since
- 1999
- Expires
- 2027-05-31
- Phone
- (714) 293-9827
- Verified
- August 17, 2026
- Licensed since
- 2001
- Expires
- 2027-07-31
- Phone
- (909) 248-5069
- Verified
- August 17, 2026
- Licensed since
- 2001
- Expires
- 2027-08-31
- Phone
- (909) 631-9805
- Verified
- August 17, 2026
- Licensed since
- 2004
- Expires
- 2027-06-30
- Phone
- (714) 328-6295
Compare the top 6 at a glance
| Company | License | Workers' comp | Licensed since |
|---|---|---|---|
| Mac Refrigeration And Air Conditioning Co | #580557 | On file | 1989 |
| Atlantic Air Conditioning Inc. | #613226 | On file | 1991 |
| Ace Rodil Heating And Air Conditioning | #631042 | On file | 1991 |
| C S D M Inc. DBA Cal Steam Company | #674646 | On file | 1993 |
| Zip Renovation & Air | #762505 | On file | 1999 |
| Service Wizards | #797071 | On file | 2001 |
Los Angeles County HVAC licensure at a glance
California licenses contractors by classification and CSLB publishes one on every record, so supply can be counted exactly: 2,674 active C-20 heating and air conditioning licenses in Los Angeles County, 30 of them registered in Diamond Bar. CSLB also publishes a real original issue date, which Washington's registry does not, so tenure is measurable here: the median Diamond Bar license has been held 8 years, and the longest-standing one dates to 1989. California law requires workers' compensation cover for C-20 licensees, so it is a legal baseline rather than a way to tell two contractors apart: 30 of Diamond Bar's 30 licenses (100.0%) carry a current policy in CSLB's file, and we do not rank on it. The contractor bond is not a signal here: 2,672 of the county's 2,674 licenses carry the same $25,000 bond California sets by statute. 206 county licenses reach their expiration date within the next 90 days. CSLB cannot link straight to a license record, so every listing above shows its number for you to type into CSLB's license lookup. How we verify.
HVAC Contractors in Diamond Bar: common questions
How many licensed HVAC contractors are there in Diamond Bar?
30 active C-20 heating and air conditioning licenses are registered in Diamond Bar, out of 2,674 across Los Angeles County. 30 Diamond Bar-registered companies passed our license verification, and the 8 on this page are the top-ranked of those. Only licenses CSLB shows as CLEAR and unexpired are listed.
Does California license HVAC contractors?
Yes. California licenses contractors by classification, and C-20 is the CSLB classification that authorises this work. 30 active C-20 heating and air conditioning licenses are registered in Diamond Bar and 2,674 across Los Angeles County, the longest-standing issued in 1989. Only CLEAR, unexpired licenses appear here.
How do I check an HVAC contractor's license in California?
Every listing above shows its CSLB license number. CSLB cannot link straight to a record, so open its license lookup and type the number in: it shows status, expiration, the contractor bond and workers' compensation cover, which California requires of C-20 licensees and 30 of Diamond Bar's 30 currently carry. 206 Los Angeles County licenses expire within 90 days.