Ask ten HVAC owners how they price a repair and you will get at least three different answers. Some use flat rate price books. Some bill by the hour plus parts. Plenty do a mix and could not tell you exactly why. Neither approach is automatically better. Each one shifts risk in a different direction, and knowing where the risk lands helps you decide.
Take a common repair: replacing a failed capacitor and cleaning a condenser coil. Assume the part costs you $18, and your fully loaded labor cost, meaning wages plus taxes, insurance, and the truck, comes to about $65 per hour of billable time. These figures are just for illustration.
Under time and materials, you bill $125 per hour plus parts with a markup. A tech who finishes in 45 minutes bills roughly $94 in labor plus maybe $45 for the part, about $139. A tech who struggles and takes two hours bills $250 plus the part, about $295. The customer is paying for the slow day.
Under flat rate, the price for that repair might be $225 no matter what. The fast tech finishes in 45 minutes and the job earns a handsome margin. The slow tech takes two hours and the margin shrinks considerably, but the customer still pays the same published price.
Time and materials keeps the risk of an unpredictable job mostly on the customer. That feels fair when the problem is unknown, like a diagnostic on an intermittent fault. The downside is that customers dislike open ended bills, and you are rewarded for being slow, which is an awkward incentive.
Flat rate keeps the risk of an unpredictable job on you, but it rewards efficiency, since a skilled tech who finishes quickly makes the business more money. Customers tend to like knowing the price before work begins. The danger is a price book that is out of date. If your costs rise and the book does not, your margin erodes without anyone noticing.
With time and materials, your revenue tracks your hours, so utilization, meaning billable hours divided by paid hours, is the number to watch. With flat rate, your revenue is detached from hours, so the number to watch is revenue per labor hour. If a job type consistently earns far less per hour than others, either the price is too low or your crews are taking too long.
Either way, you need job costing that captures actual labor and parts per job. Without it, you are guessing which repairs are winners. Our post on job costing myths covers some of the pitfalls.
A reasonable approach for many shops is to use flat rate for repetitive, well understood work, such as capacitor swaps, standard tune-ups, and common replacements, and time and materials for diagnostics and unusual problems where the scope is genuinely unknown. That way the pricing matches how predictable the job is.
Whichever way you lean, review the numbers. Pull a month of completed jobs, calculate the margin on each job type, and look at which ones fall below your target. Revisit your price book at least once a year, and sooner if parts costs jump. Supplier increases can sneak by quickly in this trade.
Pricing structure affects how your techs behave. Under flat rate, they have an incentive to work efficiently, which is good, but also potentially to rush. Under time and materials, there is less pressure to hurry, but also less reward for skill. Whichever you choose, pair it with quality tracking so speed does not come at the expense of callbacks.
There is no universally correct answer, but there is a wrong way to do it, which is to pick a model and never look at the results. Know which jobs you price which way, measure margin per job type, and update the price book regularly. The model matters less than the habit of checking it.
911 Bookkeepers works with HVAC and trades contractors across the Baton Rouge metro and surrounding parishes, helping owners see margin by job type instead of guessing.
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