Frequently Asked Questions

HVAC is not something that most Austin residents have a lot of knowledge about. Luckily, we do! McCullough is Austin’s largest family-owned residential heating and cooling company. We love all things air conditioners and furnaces, and we’re happy to share our knowledge with you. We hope these frequently asked questions address your concerns. But if not, reach out to us, no matter how silly you think the question is. You should be fully informed as you make decisions about your HVAC system. We’re here to help!

HVAC Equipment & Installation

YES! A new air conditioner can usually cut the electricity used by the old air conditioner in half. Even a 14 SEER air conditioner (this is the minimum efficiency the federal government allows to be sold) will cut the electricity used by approximately 40%. A new 90% furnace (minimum allowed by the federal government) can usually cut the gas used by the old furnace by as much as 30%.

An “oversized” furnace will warm up the house quicker, but it will use more fuel and there will be greater temperature swings in your home. A smaller furnace will maintain more even temperatures, use less fuel, but will take longer to raise the temperature. McCullough Heating & Air Conditioning will calculate the proper furnace size to maintain 80 degrees inside when it is zero degrees outside.

We don’t just look at your current equipment size and replace it with a unit of the same size. McCullough’s Comfort Consultant use several methods to ensure your system is the correct size. First, we’ll listen to any concerns you have. Is your home comfortable when the current system is operating smoothly? Then, we’ll use  Austin Energy’s progressive guideline of 1 ton per 600 square feet as a baseline. This gives us a feel for the approximate size. Finally, we will measure your home and calculate the heating & cooling load on the home. We use ACCA’s Manual J®  which incorporates information about window size & direction, walls, ceiling, floor, appliances, insulation, etc. With all this information, our experts can recommend the perfect size for your home.

Yes, this is fine. It is important that the furnace have the proper size of blower to match the air conditioner, but McCullough can determine this easily.

If you think you are going to need to install an air conditioner in the next 24 to 36 months, you probably want to have it installed with the furnace. In the Central Texas area, you may qualify for substantial cash rebates, various financing options (available with approved credit), and extended warranties when you replace your whole central heating and air conditioning system at the same time. Also, if you do install only a furnace or only a condenser, it is important to have a reputable contractor that can properly match the new component to your existing equipment and install it properly. Generally, due to lower demand, the cost will be lower to have a new system installed during the winter.

McCullough Heating & Air Conditioning services all brands of equipment. We like to say, “We sell the best and service the rest!” Our professional service technicians are some of the best trained in the industry.

The size of your central air conditioner or heat pump system will determine the amount of airflow needed. If you have any concerns, McCullough’s Comfort Consultant will measure the ductwork and determine if there is adequate ductwork, registers and grilles.


Generally allow one day for replacing a heating and air conditioning system. Installing a brand new central heating and cooling system, including duct work , may take two days. Be aware that reputable contractors will refuse to install a new air conditioning system or heat pump system when it is raining. This is due to the fact that when moisture gets inside refrigerant lines it can be very damaging and can cause reliability and maintenance issues.

Many times it is not possible for the homeowner to be home during the installation. Possibly a friend or relative can be home during the installation, or you can be there to let our installation professionals in before you leave for work. Sometimes homeowners give us a key and our installation professionals don’t even meet them until the installation is complete.

All installation work (except minor duct changes) is performed at a pre-agreed upon price and you will receive a proposal showing the total investment and detailing the work to be done, model numbers of all equipment, warranties, etc.

We always obtain all required permits and available rebates. We can take care of the electrical and gas connections also, and we can work with your electrician or plumber if you prefer.

McCullough does not have a “lowest-price guarantee” on new systems. However we do promise that your new system quote will be fair and honest.

At McCullough, your total satisfaction is our goal. We back up our work with the industry’s best guarantees and warranties. Why do customers choose us?

Integrity. Craftsmanship. Innovation. Responsiveness. Quality.

Three bids are generally enough. If McCullough is servicing your current system, or if we have installed equipment for you in the past, obtaining a proposal from us will be quick and easy. Then, you can determine if you feel the need to obtain additional bids. Your Comfort Consultant can also give you a list of customers who have had new systems installed by McCullough; you are welcome to reach out and ask why they chose McCullough.

HVAC Maintenance & Troubleshooting

How do I know when to repair or replace?

If your furnace is old, or has a serious malfunction that will cost several hundred dollars to fix, it may be wise to replace it. As a general rule of thumb, if your furnace is more than ten years old and costs more than $500 to fix, it should probably be replaced in place of repair.

If your furnace is old but not broken, deciding when to replace it can be difficult. Average life expectancy of furnaces in homes today is between 16 and 20 years.

How do I know when to repair or replace?

“An air conditioner should last about 15 years. If a system that’s more than a decade old begins to falter, consider total replacement of inside and outside units rather than a major repair. Usually only one of the system’s major components—coil or compressor—fails, but it’s usually more cost-effective to replace the whole system at once. Unmatched major components can compromise efficiency and lead to added repairs.”

– Consumer’s Report Buying Guide, Central Cooling Systems

In our years of experience, McCullough Heating & Air has found that customers prefer an accurate price based on their exact problem. Companies that offer phone quotes say they are subject to change once their technician diagnoses the problem. McCullough does not think this is fair to customers. McCullough relies on a strong onsite diagnostic procedure, including a complete inspection of your system, that provides you with a diagnosis of your problem for a small and reasonable diagnostic fee. Once the diagnostic procedure is performed, you will be shown exactly what the problem is, what the solution is, and how much it will cost. Then, and only then, do you authorize the work to be performed.

Yes, we charge a basic diagnostic fee for a professional Service Technician to come to your location, inspect your system and provide you with a diagnosis. When you add up the costs of equipment, wages, travel time, tools and equipment, insurance, and fuel, our service charge fee is quite reasonable. Other companies may try to lure you in with “No Service Charge” or an artificially low service charge, however, we’d advise you that there’s No Free Lunch! That is, you are going to pay for the service call one way or the other. At McCullough, we prefer to be upfront and fair about it: No Gimmicks!

McCullough does not recommend cleaning ducts unless some unusual event — fire, water damage, etc. — has contaminated them. Our position on duct cleaning is the same as the U.S. EPA’s recommendation. Aside from being expensive and largely unnecessary, cleaning ductwork may cause serious damage to your ducts as well as make your duct system leaky, costing you efficiency.

Yes! Because of our extreme weather, operating your heating and cooling system in Central Texas during a typical year is equivalent to putting 110,000 miles on your car. Many of us won’t go more than 5,000 miles between an oil change or 30,000 miles between a major tune-up, yet we’ll let our expensive comfort equipment run all year without much attention. While this approach may work for a time, most people end up paying heavily for this lack of maintenance in the form of higher energy bills, higher repair bills, voided warranties, reduced comfort and air quality, unplanned service interruptions and shortened equipment life.

What kind of maintenance/service plans does McCullough offer?

McCullough has several excellent maintenance plans available. Our most popular is the “McCullough GOLD Maintenance Plan” which includes two system maintenance service visits per year. The goal behind our maintenance plans is to keep your heating and cooling system in top operational condition so that it lasts longer and doesn’t fail unexpectedly. In addition to two Precision Tune-Ups annually, you’ll a host of valuable benefits such as priority service, 15% off on parts and labor, and a FREE service call if your system does fail unexpectedly (provided you’ve made repairs we have suggested during our McCullough Comfort Club).

McCullough has an excellent maintenance plan available called the Comfort Club. The goal behind our maintenance plan is to keep your heating and cooling system in top operational condition so that it lasts longer and doesn’t fail unexpectedly. Our members receive a host of valuable perks such as priority service, 15% off on parts and labor, and a FREE service call if your system does fail unexpectedly (provided you’ve made repairs we have suggested during our McCullough Comfort Club visit).

Financing & Rebates

We accept cash, personal and business checks, and credit cards including VISA, MasterCard, American Express and Discover. We also have a number of convenient financing options  (available with approved credit), including long-term, low-interest financing available for Austin Energy customers through Velocity Credit Union.

Rebates are limited-time offers that provide a cash incentive for the purchase of a specific product. HVAC rebate programs can provide thousands in savings to those looking to replace their heating and cooling systems. McCullough has saved Austin homeowners over $2M in rebates. We pride ourselves on using our expertise to save you money. Our team will take care of all the paperwork on rebates so you can sit back and enjoy your extra cash. 

About McCullough & Our Policies

Absolutely! All of our service technicians are certified and trained. We have some of the best and most dedicated service technicians in Central Texas.

McCullough Heating & Air Conditioning is open for answering questions and booking appointments Monday through Friday from 7:30 am until 5:30 pm. Hours may vary during periods of extreme weather or during holidays. Phones are always answered live by the office or answering service, 24 hours a day, 365 days a year. Emergency calls are dispatched to Service Technicians standing by when offices are closed.

McCullough Heating & Air Conditioning is a licensed air conditioning contractor in the State of Texas. We carry comprehensive insurance coverage on all workers, vehicles and equipment plus liability coverage for work done in your home or business. A certificate of insurance can be issued to you before work is done, if you so desire. In fact, we recommend that you request one from any contractor you use.

McCullough Heating & Air Conditioning has been serving customers in Central Texas since 1977. We are a family-owned and operated company that takes pride in the high quality products and services we offer our customers, many of which have been using us for their home comfort needs for many years.

We are active members of the ACCA (Air Conditioning Contractors of America), our industry’s preeminent trade association, and are longstanding members of the Better Business Bureau of Central Texas. Additionally, McCullough Heating & Air Conditioning actively participates in Austin Energy’s Residential and Multi-Family energy efficiency programs.

All installation work (except minor duct changes) is performed at a pre-agreed upon price and you will receive a proposal showing the total investment and detailing the work to be done, model numbers of all equipment, warranties, etc.

McCullough Heating & Air Conditioning does not have an overtime rate. Our rates are based on the job, not by the hour.

Saturday service is available if needed – from 8:00am to 5:00pm at regular rates.

Heating & Air Conditioning Terminology

BTU is an acronym for British Thermal Unit and is the amount of heat required to raise the temperature of one pound of water by one degree in one hour. Clear as mud? Think of BTUs as units of heat. Your furnace and air conditioner both have an equipment “size” which is determined by how many BTUs it can produce (for a furnace) or offset (for an air conditioner).

When it comes to room air conditioners, size matters. Buy one that’s too large and you could be throwing away money; buy one that’s too small and it’s likely you’re not cooling your room very efficiently. Schedule an appointment with one of our Comfort Consultants to learn what size AC unit you need to cool your room or house.

SEER stands for Seasonal Energy Efficiency Rating. The SEER rating on your air conditioner tells you how efficient it is. Some air conditioners use less energy to provide the same amount of cooling as others. It’s kind of like miles per gallon in a car – cars with a higher miles per gallon rating are more efficient. You pay less in gasoline over time and it’s better for the environment. SEER is the same. The higher the SEER on your AC, the lower your electricity bill – and the lower your environmental impact.

Scroll to Top