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TRUSTED BY DIAMOND BAR, CA HOMEOWNERS

  • Average homeowner rating star icon4.7
    Average homeowner rating
  • Verified reviews icon330
    Verified heating and air conditioning services reviews

Find Heating and air conditioning pros in Diamond Bar

Avatar for Air-Tech Air Conditioning & Heating Inc
Air-Tech Air Conditioning & Heating Inc
4.5(
202
)

Serving Diamond Bar, CA and surrounding areas

Approved

In business since 1988

Free estimates

Warranties offered

"In preparation for replacing my HVAC system, I went through a few different estimates. The reason I chose Air-Tech was not because of price, but because I was impressed by the details provided to me. Rod was great. We went into the attic, reviewed all the components inside and out. And we discussed the scope of the work. Once I agreed, he gave me a start date\time. The crew showed up on time and worked hard for two days. Not only was I comfortable with Rod, but the crew was great. My new system is in place and I couldn’t be happier that I chose Air-Tech. If you’re in the market for a new HVAC system, do yourself a favor and call them. You won’t be disappointed."
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+8

44 neighbors recently requested a quote
Recommended by93%of homeowners
Avatar for Top Energy Solutions, Inc.
Top Energy Solutions, Inc.
4.9(
62
)

Serving Diamond Bar, CA and surrounding areas

Approved

In business since 2019

Free estimates

Warranties offered

"Great job, Workers are great and they know HVAC. They are a great team and very nice people. Owner is very sincere & reliable. He will work with you on the best equipment...... you get what you pay for.!!!!!!!!"
Roof Replacement  - Owens Corning Shingle Roof
New Windows Installation in Hollywood
5 Ton Furnace Replacement
Attic insulation
New Mini Split - Daikin Emura

+87

Response time1 day
Response rate98%
6 neighbors recently requested a quote
Avatar for HD MECHANICAL INC
HD MECHANICAL INC
5.0(
26
)

Serving Diamond Bar, CA and surrounding areas

Approved

Super Service Award Winner

In business since 2022

Free estimates

Emergency services offered

"THE OWNER; CHRIS ROBINSON WAS AMAZING, EXCEPTIONAL CUSTOMER SERVICE, GREAT PEOPLE SKILLS. UNBEATABLE PRICING ON UNITS & LABOR I HAD BEEN QUOTED VERY HIGH BY 4 OTHER COMPANIES, HD MECHANICALs PRICING WAS HONESTLY EXTREMELY AFFORDABLE. HIGHLY RECOMMENDED FOR ALL YOUR HVAC NEEDS!!"
Heating & A/C Project
Heating & A/C Project
Heating & A/C Project
Heating & A/C Project
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+14

56 neighbors recently requested a quote
Recommended by76%of homeowners
Avatar for All City Plumbing, Air & Electrical
All City Plumbing, Air & Electrical
4.9(
270
)

Serving Diamond Bar, CA and surrounding areas

Approved

Super Service Award Winner

In business since 2009

Emergency services offered

Warranties offered

The industry's best technicians make the happiest customers. Turn to the pros at All City Plumbing, Air, & Electrical for all of your plumbing, HVAC, and electrical needs. Proudly serving San Bernardino, Riverside, Los Angeles, and Orange Counties. We have over 5000s 5 star reviews across the web from our thrilled customers. Our company goal is to make sure that we have 100% customer satisfaction. We have options and payment plans that can fit in everyones budget. We provide free estimates and you only pay when you're happy. It's no surprise we've received the Angie's List Super Service Award six years in a row! Established in 2009. ACP was created to deliver exceptional service with the highest quality of craftsmanship. We guarantee you will be happy with our services in that we offer a money back guarantee. Our technicians are regarded by their peers to be some of the best in the industry. Our service experts are continuously trained. There isn't a plumbing or hvac problem we can't solve. We have the experience, knowledge and focus to solve any problem you may have. Give us a call today and let us earn your confidence.

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+42

14 neighbors recently requested a quote
Recommended by97%of homeowners
Avatar for Trabuco Air
Trabuco Air
4.6(
130
)

Serving Diamond Bar, CA and surrounding areas

Approved

In business since 1996

Free estimates

Emergency services offered

"Sam, who came out to give me an estimate for a new system, found out that the old fan motor was the culprit and recommended that we just repair the motor. He explained things in detail, helped us to save money in a genuinely sincere attitude, I was impressed how good his service was, and I recommend him for any HVAC issues. I will be using him in the future."
Response time5 hrs
Recommended by94%of homeowners
Avatar for SO CAL BOYS HEATING & AIR INC
SO CAL BOYS HEATING & AIR INC
5.0(
54
)

Serving Diamond Bar, CA and surrounding areas

Approved

Super Service Award Winner

In business since 2022

Free estimates

Emergency services offered

"George is a true professional. He very patiently explained several options for replacing my hvac system. In the end I hired another pro for my project, only because they have been maintaining my system for many years. I would definitely consider George and SO CAL BOYS HEATING and AIR in the future."
2 ton condenser
2 ton furnace
Response time30 mins
27 neighbors recently requested a quote
Recommended by31%of homeowners
Avatar for Temp Air System, Inc.
Temp Air System, Inc.
4.8(
54
)

Serving Diamond Bar, CA and surrounding areas

Approved

In business since 2002

Free estimates

Credit card accepted

"We had Temp Air install our AC unit. The best decision we ever made. They were fast, reliable and dependable. Excellent customer service, did a phenomenal job. After a couple of years something was going on with our unit, I called them and immediately they send out a technician Juan, who was phenomenal. He explained what the issue was and resolved it asap! Highly recommend this company!"
Mini Split Installation
Mini Split Installation
Mini Split Installation
Mini Split Installation
Mini Split Installation

+14

Response time10 hrs
Response rate99%
7 neighbors recently requested a quote
Avatar for Penguin Heating and Air Inc
Penguin Heating and Air Inc
5.0(
15
)

Serving Diamond Bar, CA and surrounding areas

Approved

Super Service Award Winner

In business since 2025

Free estimates

Emergency services offered

Penguin Heating and Air Inc is here to help! We offer a variety of HVAC services from service to installations. We are based out of the Placentia, CA area. Give our team a call today. We're looking forward to working with you!\n

Diamond Bar
Diamond Bar
Diamond Bar
Furnace Install
AC Condenser

+6

27 neighbors recently requested a quote
Recommended by6%of homeowners
Avatar for Service Champions, LLC
Service Champions, LLC
4.4(
50
)

Serving Diamond Bar, CA and surrounding areas

Approved

In business since 2000

Free estimates

Warranties offered

"Kayvan was a wonderful service tech! He was on time and professionally checked out the water heater and the HVAC system. He was so polite and friendly. He explained the need for a new filter in the heating unit and showed me photos of the unit located in the attic. He also offered to do a friendly deed for free, which I greatly appreciated, He’s a great asset to Service Champions!"
Area Drain Cleaning
Plumbing
Plumbing
Garbage Disposal
Drain Cleaning

+13

Response time4 hrs
Recommended by79%of homeowners
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Heating and Air Conditioning questions, answered by experts

Signs that your air conditioner capacitor is bad or failing include a range of symptoms. The AC unit may not turn on at all, or it might struggle to start before shutting down randomly or in the middle of a cooling cycle. You might hear a humming or banging noise when it attempts to start, or the compressor might hum without the unit actually running. Other indicators include a smell or smoke coming from the unit, the blower circulating room-temperature air instead of cold air, and an unexpected increase in your energy bills.

Yes. It's normal for the AC compressor to cycle on and off intermittently in dry mode as it maintains the desired humidity level. The compressor cycles to prevent over-dehumidification and to maintain a comfortable indoor environment. This cycling behavior ensures efficient operation and optimal humidity control, contributing to the overall effectiveness of the dry mode function in your AC system.

Most HVAC companies recommend against setting your AC below 70 as it could freeze up the system and cause more problems. Regardless of how hot it is outside, there is generally a 20 degree difference between the outside and inside temperatures, so even if it’s 100 degrees outside, your AC will likely not be able to cool your home to 70 degrees.

You can protect your air conditioner in the winter by turning off the power at the thermostat and performing routine HVAC maintenance in the spring. Regular maintenance, cleaning, and repair of your AC unit helps protect it and extend its life span. If you have a window AC unit, remove it from the window and store it in a dry place during the winter. Window units cannot withstand freezing temperatures. Keeping them in your window also allows cold air to seep into your home.

If your AC suddenly stops working, the first thing to check is your thermostat settings. Ensure the thermostat is set to the appropriate temperature and mode (cooling). Sometimes, a simple adjustment or replacing the batteries in the thermostat can resolve the issue. If that’s not the issue, look to see if the circuit breaker tripped. These basic checks can often identify simple fixes before you need to call for professional assistance.

The Diamond Bar, CA homeowners’ guide to heating and air conditioning services

From average costs to expert advice, get all the answers you need to get your job done.