Lubbock, TX · since 1992

AC, heat and plumbing. One call gets it all.

We're a Carrier and Mitsubishi dealer with master plumbers on staff. We fix every brand. Emergency calls go out 24 hours a day, weekends and holidays too.

Call (806) 798-1738 See what we fix

NATE-certified techs
Flat-rate pricing
Open 24/7 for emergencies

What's going on at your place?

An A/C tech comes out. Carrier, Mitsubishi or whatever brand you've got.Same number for all three: (806) 798-1738.

A row of condenser units along the brick wall of a building, a Duncan job — **4.3** 46 Google reviews
Our job photo, April 2025

Dealer and installer for Carrier Mitsubishi Electric Rinnai Navien Noritz NATE-certified BBB A+

What we fix

Heat, AC and plumbing from one shop.

Homes, shops and offices. We install, repair and maintain all of it, and we service every brand, including ones we don't sell.

A condenser set on a pad in a narrow side yard between a brick wall and a wood fence

Cooling

Air conditioning

Repair, new installs and ductless mini-splits.

Central AC and heat pumps
Mitsubishi ductless
Ductwork and sheet metal

A technician checking the burners of a gas furnace with a handheld meter

Heating

Heating and furnaces

Gas, electric or oil. Emergency repairs any hour, weekends too.

Furnace and heat pump repair
New heating installs
Carbon monoxide checks

A Navien tankless water heater mounted on a plywood wall with new copper and PVC lines

Plumbing

Plumbing and water heaters

Master plumbers for leaks, drains, gas lines and remodels.

Tank and tankless water heaters
Trenchless sewer line replacement
Salt-free systems for Lubbock's hard water

Commercial

Commercial HVAC

Rooftop units, chillers and plumbing for offices and stores.

Install, repair, scheduled service
Backflow prevention
Leak detection and video pipe inspection

Recent work

Real jobs from our crew.

No stock photos here. These are installs our crew finished in 2025.

Three new Carrier gas furnaces standing side by side in one mechanical room, with new flues and copper lines — **Heating · May 2025**Three Carrier gas furnaces side by side in one mechanical room.

Three condensers lined up behind a chain-link fence along a building, seen from the end of the row — **Cooling · April 2025**A row of condensers along a brick building.

Why Lubbock calls us

Local owners. Honest answers. Flat prices.

Your AC company shouldn't blow hot air either. You get an honest opinion and a plain explanation of the work before it starts.

Founded1992

Started by Dennis Duncan Jr., a licensed master plumber and HVAC contractor, and Davis Moore, a master electrician with over 40 years in the trade. The whole crew lives and works in the Hub City.

Flat-rate pricing

You get the price for the job, not a meter that runs while the tech works.

24/7, holidays too

Furnace quits on a Sunday in February? Call. Emergency repairs run around the clock.

We register your warranty

New equipment gets registered with the maker for you, so the full manufacturer warranty counts.

Every brand serviced

We sell Carrier and Mitsubishi. We fix and maintain whatever is already in your closet.

How a service call goes

From "it's broken" to fixed, in four steps.

Same steps for a dead AC in July, a cold furnace in January or a water heater that gave out.

STEP 01
You call
(806) 798-1738, any hour. Tell us what's happening and where you are.
STEP 02
We call back fast
The office calls you back and sends a tech out.
STEP 03
We show you the problem
The tech explains it in plain English and gives you options with flat-rate prices.
STEP 04
Fixed and backed
One year on our workmanship. New equipment gets registered for the maker's warranty.

Reviews

What customers say about Steven and Barbara.

Word for word from Google. In both reviews, Barbara took the call and Steven came out.

"Called on Sunday morning at 8:00 am during an extreme winter event. Got a return phone call from Barbara within 5 minutes. She dispatched Steven and he was here within an hour. Steven did a great job explaining the issue and got us fixed up as quickly as possible. We have done business with Duncan for almost 10 years and appreciate their professionalism."

Shannon PettitGoogle review

"I was referred to Duncan Heating and Air from the Carrier warranty representative. The associate took my information, called me back within 10 minutes, and dispatched an A/C tech to visit my home between 2PM and 2:30PM. Steven showed up precisely at 2:00PM. Steven was friendly, knowledgeable, efficient, and honest."

Stacey NashGoogle review

Excellent service and staff. This company has great integrity, ethics and customer service. They get straight to work and the scope service was great.

4.3 on Google from 46 reviewsCarrier and Mitsubishi factory-authorized dealerBBB A+

Maintenance agreements

Two tune-ups a year. No overtime rates when it breaks.

Plan members get the AC done in spring and the furnace in fall, first pick of time slots, and no overtime charge on an emergency call.

$100 A/C system tune-up. Ask about it when you call.

Spring, cooling

Test thermostat and controls
Check the refrigerant charge
Wash the condenser coils
Flush the condensate drain
Tighten electrical connections

Fall, heating

Clean burners and nozzles
Inspect the heat exchanger
Measure gas pressure
Test shut-off valves
Check for carbon monoxide

Warranty

Our warranty, plus the maker's, registered for you.

All our work comes with a 100% satisfaction guarantee.

1Year on our workmanshipEvery repair and install.
10Years on residential CarrierManufacturer warranty on Carrier home equipment.
12Years with MitsubishiManufacturer warranty on Mitsubishi Electric systems.
$Financing with approved creditThrough Wells Fargo and AC Credit. Ask about it when you call.

Service area

Lubbock and the South Plains, out to eastern New Mexico.

Our shop is on the Marsha Sharp Freeway. Not sure we reach you? Call and ask.

Visit the shop

7437 Marsha Sharp Fwy W
Lubbock, TX 79407

Office, Mon to Fri: 8 am to 5 pm
Sat and Sun: Office closed
Emergencies: 24 hours, every day

(806) 798-1738

Lubbock
Wolfforth
Slaton
Abernathy
Levelland
Plainview
Brownfield
Lamesa
Snyder
Hereford
Big Spring
Andrews
Eastern New Mexico
and more nearby

FAQ

Questions we hear on the phone.

Don't see yours? Call (806) 798-1738 and ask.

Do you work on brands you don't sell?

Yes. We're a Carrier and Mitsubishi dealer, but we service and maintain every make and model.

Can one company do my AC and my plumbing?

Yes. We have NATE-certified HVAC techs plus master plumbers and journeymen. One call covers both.

Do you come out at night or on weekends?

For emergencies, yes: 24 hours a day, weekends and holidays included. Plan members pay no overtime on emergency calls.

How often should my furnace get serviced?

Once a year, best in the fall before it turns cold. A heat pump gets a look in spring and fall.

Which tankless water heaters do you install?

Rinnai, Navien and Noritz. We're factory-authorized to install and service all three. We also repair and replace tank heaters.

Can you help with our hard water?

Yes. We test your water and can install a salt-free conditioning system made for Lubbock's hard water.

Too hot, too cold, or dripping? Call Duncan.

Emergency service runs day and night. Tell us what's wrong and we'll send the right tech.

Call (806) 798-1738 Ask about tune-ups

Office Mon to Fri, 8 to 5. Emergency service 24/7.