1,311 HVAC contractors ranked by CR ScoreUpdated 0 paid placements in this rankingHow we rank →
Best overall in Diamond Bar: All Pro Cooling, Heating, Plumbing & Electrical, CR Score 64/100; 4.8★ from 7,425 Google reviews; open 24/7.
Best for emergencies (open 24/7): Metz Air Control, posts 24/7 hours; ranked #2 of 1,311.
Most-reviewed: Service Champions Plumbing, Heating & AC, 6,978 Google reviews at 4.9★, the most of 1,311 ranked after All Pro Cooling, Heating, Plumbing & Electrical; ranked #7.
Rankings can't be bought. Contractors can't pay to change their rank or score. How we rank
1,311 Diamond Bar HVAC contractors are ranked here by CR Score, from ten published factors. 444 are open 24/7, 1,003 open Saturdays and 679 open Sundays, based on posted hours. The median Google rating is 4.9★ across 1,311 rated businesses.
| Rank | Business | CR Score | Google rating | Based in | Hours | Best for |
|---|---|---|---|---|---|---|
| 1 | All Pro Cooling, Heating, Plumbing & Electrical | 64 | 4.8★ (7,425) | Ontario, 16 mi away | 24/7 | Overall |
| 2 | Metz Air Control | 64 | 4.9★ (969) | Chino, 7 mi away | 24/7 | Emergencies |
| 3 | Service Hero Plumbing, HVAC, and Electrical | 64 | 4.8★ (1,506) | Covina, 7 mi away | 24/7 | — |
| 4 | Steve's Five Star Service | 64 | 4.9★ (1,292) | Upland, 9 mi away | 24/7 | — |
| 5 | Home Comfort USA | 63 | 4.8★ (2,813) | Anaheim, 12 mi away | 24/7 | — |
| 6 | Klaus & Sons Plumbing, Heating & Air Conditioning | 63 | 4.9★ (977) | Montclair, 9 mi away | 24/7 | — |
| 7 | Service Champions Plumbing, Heating & AC | 63 | 4.9★ (6,978) | Brea, 8 mi away | Sat · Evenings | Most reviews |
| 8 | Rooter Hero Plumbing & Air | 63 | 4.8★ (802) | Montclair, 8 mi away | 24/7 | — |
| 9 | Air Concepts Air Conditioning and Heating | 62 | 4.9★ (995) | Anaheim, 12 mi away | 24/7 | — |
| 10 | Veteran Air | 62 | 4.9★ (1,091) | Anaheim, 13 mi away | 24/7 | — |
Ordered by CR Score, a 0–100 score from ten published factors. Paid placement never changes the order.
Scores below: based on 8 of 10 factors; credentials and recency not yet collected. Hatched segments mark factors we don't have yet.
Ranked #1 in Diamond Bar
Based in Ontario, 16 mi away
Ranked #1 because of its Google rating and review volume: 4.8★ from 7,425 Google reviews, the most in Diamond Bar.
Based in Chino, 7 mi away
Ranked #2 because of its Google rating and trade focus: 4.9★ from 969 Google reviews, listed on Google as “Air conditioning repair service”.
Based in Covina, 7 mi away
Ranked #3 because of its Google rating and trade focus: 4.8★ from 1,506 Google reviews, listed on Google as “HVAC contractor”.
Based in Upland, 9 mi away
Ranked #4 because of its Google rating and trade focus: 4.9★ from 1,292 Google reviews, listed on Google as “Air conditioning contractor”.
Based in Anaheim, 12 mi away
Ranked #5 because of its Google rating and trade focus: 4.8★ from 2,813 Google reviews, listed on Google as “HVAC contractor”.
Based in Montclair, 9 mi away
Ranked #6 because of its Google rating and trade focus: 4.9★ from 977 Google reviews, listed on Google as “HVAC contractor”.
Based in Brea, 8 mi away
Ranked #7 because of its Google rating and trade focus: 4.9★ from 6,978 Google reviews, listed on Google as “HVAC contractor”.
Based in Montclair, 8 mi away
Ranked #8 because of its Google rating and trade focus: 4.8★ from 802 Google reviews, listed on Google as “HVAC contractor”.
Based in Anaheim, 12 mi away
Ranked #9 because of its Google rating and trade focus: 4.9★ from 995 Google reviews, listed on Google as “HVAC contractor”.
Based in Anaheim, 13 mi away
Ranked #10 because of its Google rating and trade focus: 4.9★ from 1,091 Google reviews, listed on Google as “HVAC contractor”.
Based in Anaheim, 12 mi away
Ranked #11 because of its Google rating and trade focus: 5.0★ from 1,899 Google reviews, listed on Google as “HVAC contractor”.
Based in Anaheim, 12 mi away
Ranked #12 because of its Google rating and trade focus: 4.7★ from 2,250 Google reviews, listed on Google as “HVAC contractor”.
Based in Brea, 9 mi away
Ranked #13 because of its Google rating and trade focus: 4.9★ from 547 Google reviews, listed on Google as “HVAC contractor”.
Based in Yorba Linda, 11 mi away
Ranked #14 because of its Google rating and trade focus: 4.9★ from 764 Google reviews, listed on Google as “Air conditioning contractor”.
Based in Corona, 15 mi away
Ranked #15 because of its Google rating and trade focus: 4.9★ from 1,325 Google reviews, listed on Google as “HVAC contractor”.
Based in San Dimas, 5 mi away
Ranked #16 because of its Google rating and trade focus: 4.9★ from 251 Google reviews, listed on Google as “HVAC contractor”.
Based in Diamond Bar
Ranked #17 because of its Google rating and trade focus: 4.9★ from 89 Google reviews, listed on Google as “HVAC contractor”.
Based in Brea, 10 mi away
Ranked #18 because of its Google rating and trade focus: 4.9★ from 439 Google reviews, listed on Google as “HVAC contractor”.
Based in Santa Ana, 21 mi away
Ranked #19 because of its Google rating and trade focus: 4.9★ from 2,852 Google reviews, listed on Google as “HVAC contractor”.
Based in Corona, 16 mi away
Ranked #20 because of its Google rating and trade focus: 4.9★ from 1,213 Google reviews, listed on Google as “HVAC contractor”.
Based in Chino, 5 mi away
Ranked #21 because of its Google rating and trade focus: 5.0★ from 392 Google reviews, listed on Google as “HVAC contractor”.
Based in Rancho Cucamonga, 13 mi away
Ranked #22 because of its Google rating and trade focus: 4.9★ from 705 Google reviews, listed on Google as “Air conditioning contractor”.
Based in Orange, 16 mi away
Ranked #23 because of its Google rating and trade focus: 4.8★ from 1,840 Google reviews, listed on Google as “HVAC contractor”.
Based in Covina, 6 mi away
Ranked #24 because of its Google rating and trade focus: 4.7★ from 426 Google reviews, listed on Google as “HVAC contractor”.
Based in Westminster, 22 mi away
Ranked #25 because of its Google rating and trade focus: 4.8★ from 4,319 Google reviews, listed on Google as “HVAC contractor”.
#1 to #25 are shown in full above. Here are #26 to #50, in CR Score order; each links to its profile. We publish the top 50 of 1,311 ranked HVAC contractors here; the rest are on their profiles.
20 more HVAC contractors within 25 mi that we can't rank yet: too few reviews, or a trade we couldn't confirm. Listed A to Z.
| Business | Google rating | Distance |
|---|---|---|
| ABR Air Conditioning, Heating, and Refrigeration | 5.0★ (2) | In Diamond Bar |
| Ayman Ibrahim HVAC Contractor | 5.0★ (84) | 9 mi |
| BOMING Air Conditioning & Heating HVAC | 5.0★ (2) | 8 mi |
| Budget Air Conditioning & Heating | In Diamond Bar | |
| Golden Construction Chino | 5.0★ (2) | 8 mi |
| GOMEZ Air conditioning, LLC | 3.0★ (2) | 3 mi |
| HaoShi Carbon Fiber Co., Ltd | In Diamond Bar | |
| Integrity Mechanical Corporation | 5.0★ (2) | 7 mi |
| jmdequipmentsales | In Diamond Bar | |
| Liberty Air | 5.0★ (2) | 3 mi |
| Living Air Design | 5.0★ (76) | 8 mi |
| Mac Refrigeration & Air Conditioning | 3.0★ (2) | In Diamond Bar |
| Penguin Heating and Air | 5.0★ (144) | 13 mi |
| Professional Heating & Air | 3.0★ (2) | 6 mi |
| Purcell AC Repair Services | 5.0★ (32) | 4 mi |
| Sam's Refrigeration Air Conditioning | In Diamond Bar | |
| Steve Hempel Air | 5.0★ (2) | 6 mi |
| Viking Air Inc. | 5.0★ (2) | 3 mi |
| West Covina Hvac Services | 5.0★ (2) | 6 mi |
| Zach Taylor Heating And Air LLC | 5.0★ (63) | 8 mi |
National price ranges in USD, not adjusted for Diamond Bar. Each row names its basis and the month we checked it.
| Job | Low | Typical | High | Basis | Checked |
|---|---|---|---|---|---|
| AC replacement | $3,887 | $5,978 | $8,073 | Per system, installed (unit plus labor); typical range of customer-reported jobs. US national range | October 2026 |
| Furnace replacement | $2,823 | $4,814 | $6,896 | Per system, installed; typical range of customer-reported jobs. US national range | October 2026 |
In California, Contractors State License Board (CSLB) licenses C-20 Warm-Air Heating, Ventilating and Air-Conditioning contractor license.
Jobs of $1,000 or more in labor and materials (from January 1, 2025).
No chip usually means we have not matched a state record yet. Check the lookup yourself before you hire.
Guide checked October 2026. How we verify licenses
California's HVAC demand peaks during summer heat waves and the first cold snaps. Spring and fall are the easiest times to book maintenance.
We scored 1,311 Diamond Bar HVAC contractors on ten factors, weighted as shown. A business is ranked when its trade is confirmed and it has 3 or more Google reviews or a claimed profile. A business with no Google reviews scores zero on rating, review volume and recency. Other unknown factors are left out, not counted as zero. Scores last refreshed October 23, 2026.
Paid placement never changes a rank or score. Featured businesses are paid, labelled, limited to 3 and shown above the ranking, outside it.
| Factor | Weight | Computed from | In Diamond Bar data |
|---|---|---|---|
| Reputation | 25% | Google star rating, adjusted for how many reviews back it | Measured |
| Credentials | 15% | Active state license, bond and workers’ comp on file | Not yet collected |
| Review volume | 10% | Number of Google reviews, compared with the most-reviewed business on the list | Measured |
| Recency | 5% | Share of reviews from the last 12 months | Not yet collected |
| Availability | 5% | Weekly open hours, Saturday, Sunday, 24/7 or same-day | Measured |
| Trade focus | 10% | How clearly the business does this trade (its Google category and name) | Measured |
| Proximity | 5% | Based in the city scores highest, less the farther away it is | Measured |
| Claimed profile | 10% | The business has claimed its ContractorsRanked profile (free or paid earn the same) | Measured |
| Partnered | 5% | The business links to ContractorsRanked from its own website with our badge, checked periodically | Measured |
| ContractorsRanked reviews | 10% | Verified customer reviews collected by ContractorsRanked: their rating and how many there are | Measured |