It's 2:40 on a 97-degree afternoon. Your tech has diagnosed a failed dual-run capacitor, opens the truck, and the bin is empty. The nearest supply house is 25 minutes away. They drive there and back, and the customer sits in a hot house for another hour. The next two calls on the board slide into the evening. Nobody knew the truck was out, because the count lives on a clipboard.
That's the problem HVAC inventory management software is supposed to solve. It should tell you what's on every truck right now, flag low stock before the bin is empty, and tie every part pulled to its job and invoice. Here's what to require, what to test, and how to set it up so it holds through a full cooling and heating season.
What a supply-house run actually costs
Start with the number your techs will never write down. This example is illustrative, so swap in your own figures.
The BLS puts median HVAC technician pay at $61,010 a year, or $29.33 an hour (May 2025). That's the wage, not the cost. Across private industry, wages and salaries are 70% of what employers spend on compensation, and benefits are the other 30%. So to get the loaded cost, divide the wage by 0.70 rather than adding 30% to it: $29.33 ÷ 0.70 = $41.90 an hour.
- One supply-house run: about an hour of tech time ($41.90) plus about $15 for fuel and the truck, so $56.90 in direct cost.
- One run per tech per week, across 15 techs and 50 working weeks, is 750 runs.
- 750 runs × $56.90 is $42,675 a year.
That's before the hour you couldn't bill, the call that slid to tomorrow, and the review from the customer who waited. In peak season those are the real costs. The BLS notes that HVAC techs may be on call for emergencies and sometimes work overtime or irregular schedules during peak heating and cooling seasons. An hour lost to a parts run in July is an hour you don't get back, and it's often paid at overtime rates.
Why HVAC inventory is harder than most trades
Three things make HVAC stock hard to manage on a clipboard.
The stock changes with the season. Summer trucks run on capacitors, contactors, fan motors and refrigerant. Fall trucks need igniters, flame sensors, inducer motors and pressure switches. A truck stocked for July is wrong for November, and a minimum level that doesn't change with the season is always half wrong.
Refrigerant is regulated, and the record starts on the truck. On appliances holding 50 pounds or more, the EPA requires owners and operators to keep servicing records documenting the date and type of service, as well as the quantity of refrigerant added. Technicians who recover refrigerant during disposal keep their own records of location, date, type and amounts. Your commercial customers will ask you for those numbers. Inventory software isn't a compliance system and won't keep those records for you. But if refrigerant comes off the truck without being logged against a job, you're rebuilding the numbers from memory.
Parts prices move constantly. Trade press runs regular manufacturer price-increase lists. On ACHR News's September 2026 list, one plumbing and HVAC supply maker announced increases of 5% to 15% across its product groups. If what you paid for a part on the truck and what you charge for it live in different places, margin quietly leaks every month.
What HVAC inventory management software should do
Use this as your checklist, and bring it to every demo. Each item has a test you can run in front of the vendor in a few minutes.
1. Track stock on every truck, not only the warehouse
Each tech's truck stock is its own count. A tech or dispatcher should be able to see what's on truck 7 from a phone, and the office should be able to see who is carrying a given part.
Test it: ask the vendor to show one part's quantity on three different trucks at once.
2. Deduct parts when they're used on a job
When the tech logs a part on the job, it should come off that truck's count, and it should reach the invoice without anyone retyping it. Refrigerant should be logged the same way, so each job shows what was added.
Test it: complete a job on the mobile app using one capacitor and the refrigerant you charged. Check the truck count, job record and the invoice you generate from the job.
3. Alert on low stock in the warehouse and on the truck
You need two kinds of minimum. A warehouse minimum tells the office when to reorder. A truck minimum tells the tech what to pull before leaving the shop, not in the customer's driveway.
Test it: set a warehouse minimum of 3 on a contactor, draw it down to 2, and see who gets told and how. Then set a minimum on one tech's truck, use stock below it, and see where the tech finds out.
4. Scan instead of type
Barcode or QR scanning from the phone for looking up parts and moving stock. Techs won't type part numbers standing next to a condenser.
Test it: look up a part by scanning its label, then move 10 filters by scanning. Count the taps.
5. Move stock between trucks with a record
When one tech hands another a part in a parking lot, it should take a scan, not a text message, and both trucks' counts should change.
Test it: transfer a part from one tech to another and check the history on both sides.
6. Make warehouse counts fast and honest
A physical count of the warehouse should compare to the system count automatically and show the variance by part. You also need a way to freeze stock movement in that warehouse while the count is happening, or the numbers change under you. Trucks are a different job: ask how the tech and office know what each truck should be carrying, and what happens when it drops below that.
Test it: run a count on one warehouse with a deliberate mismatch, then try to move stock out of it mid-count. See how the variance shows up and whether the move is blocked.
7. Keep a full audit trail
Who changed what, when, and why, for every stock movement. That's how you find shrinkage, and how you answer a customer asking where their refrigerant went.
Test it: make an adjustment, then find it in the history for that part.
8. Tie parts to the dispatch decision
The best inventory data is useless if dispatch can't use it. Before sending a tech to a no-cool call that needs a specific part, the assignment should account for which trucks actually carry it, without the dispatcher opening every truck's list.
Test it: put a required part on a job, make sure only one truck has it, and see who the job goes to.
Setting it up so it survives a season
Most HVAC inventory management software rollouts fail in the first month, not in the demo. These habits keep yours alive:
- Start with the 50 parts that cause most runs. Don't load 3,000 SKUs on day one. Ask your techs which parts send them to the supply house. That list is short.
- Set two sets of minimums. One for cooling season and one for heating season. Switch them in the shoulder month, when you're already doing tune-ups.
- Decide how you count refrigerant. Most inventory systems, ours included, count stock in whole units. Pick one unit, the cylinder or the pound, and use it on every job so the numbers add up.
- Count the warehouse weekly at first. Once variances shrink, move to every other week. The first month's variance tells you where the leaks are. Have techs check their truck's low-stock list at the start of each week.
- Log refrigerant on every job, not only big ones. Getting the habit right on residential calls means the commercial numbers are there when you need them.
- Give techs one job, not five. Scan it, use it, done. If logging a part takes more than a few taps, it won't happen.
For the basics of truck stock versus warehouse stock, start with what inventory management means in field service. Plumbing shops face a different version of this problem, which is covered in our guide to plumbing inventory software.
Where FSM Navigator fits
FSM Navigator's inventory management tracks stock in your warehouses and on each technician's truck. Warehouse minimums trigger low-stock email alerts to the owner and inventory manager. Each tech sets their own truck minimums and sees low items in the mobile app. Techs look up parts in the app and see which warehouses and which techs are holding a given part; office staff with inventory access scan barcodes and QR codes and move stock between warehouses and trucks.
Parts logged on a job come off that tech's stock and prefill the invoice when you generate it. Refrigerant is set up as an inventory item and logged on each job like any other part. Warehouse counts calculate the variance for you and freeze stock movement in that warehouse until the count is finished, and every stock movement records who made it and when.
When a job lists required parts, intelligent dispatch checks each tech's truck for them, either as a requirement or as a preference, so the call goes to someone who can finish it. The HVAC page shows how the rest of the platform fits a heating and cooling shop.
Inventory is part of the Enterprise plan. That's the plan built for shops running a warehouse and a fleet, where an inaccurate count costs jobs, not one misplaced part. Start a trial and load your top 50 parts onto one truck this week.