Last updated: October 7, 2026 · Independent buyer’s guide · We do not sell rankings or coverage.
HVAC inventory management is the process of controlling the parts, equipment and refrigerant you hold in your warehouse and on every service truck, so that technicians have what they need and every part used is charged to a job. In practice it rests on five routines: replenishing truck stock, posting parts usage from each job, tracking serialized equipment, issuing purchase orders to supply houses, and counting stock on a regular cycle. Field service platforms such as ServiceTitan and Simpro handle most of these natively, while Housecall Pro relies on QuickBooks or an add-on such as Ply for quantity tracking, and FieldEdge presents its inventory management as part of its QuickBooks integration.
Key takeaways
- Treat each truck as a stocking location with minimum and maximum quantities, and replenish it from parts posted on jobs.
- Parts used but never posted to an invoice are a common cause of lost margin and inaccurate inventory.
- ServiceTitan and Simpro document truck and warehouse stock, purchase orders and counts natively. ServiceTitan also documents serialized inventory.
- Housecall Pro’s help center points customers to QuickBooks Online Plus for inventory tracking and lists Ply as an integration. Service Fusion includes inventory on its Plus and Pro plans and sells it as an add-on on Starter.
- QuickBooks Online tracks inventory only on the Plus and Advanced plans, and the costing method you choose (FIFO or average cost) cannot be changed later.
- Refrigerant is inventory with a compliance trail: EPA rules require service records of the amount and type of refrigerant added to appliances holding 50 or more pounds of ozone-depleting (class I or class II) refrigerant.
Who this guide is for
This guide is written for operations managers and controllers at US HVAC contractors running roughly 5 to 100 service trucks. You probably already use a field service platform for dispatch and invoicing, and you suspect that its inventory figures do not match what is on the shelves and in the vans.
For recurring maintenance plans, see our guide to HVAC service agreement software.
How HVAC inventory moves through the business
Warehouse stock and truck stock
Warehouse stock covers equipment awaiting installation and slower-moving parts. Truck stock is a standard load of fast-moving repair parts such as capacitors, contactors, igniters, flame sensors, filters and refrigerant, sized so a technician can finish most calls without a supply house run.
Both are inventory on the balance sheet. A part becomes job cost when it is used on a job, not when it is bought or loaded on a truck, so a warehouse-to-truck transfer changes location but not value.
Parts usage posted from jobs
When a technician adds a part to the invoice in the mobile app, that entry bills the customer (or records the part against an agreement or warranty job), reduces stock at the truck location, and moves the cost to that job. If the entry is skipped, the customer is not charged, the truck still shows stock that is gone, and the job looks more profitable than it was.
Truck replenishment
A good system builds each truck’s refill list from the parts posted on jobs, compares it with the truck’s minimum quantities, and creates either a warehouse transfer or a purchase order. Supply house counter purchases are the hardest to control, because the part often goes into a job before the office sees the supplier invoice.
Purchase orders to supply houses
A purchase order records what you committed to buy, at what price, and for which job or truck. Matching the supplier invoice to the order and the receipt is how you catch price changes and short shipments. Without purchase orders, supplier bills tend to be coded straight to expense and inventory value drifts.
Serialized equipment
Condensers, furnaces, air handlers and heat pumps carry serial numbers that you need for warranty registration, recalls and future service. Serialized tracking records each unit from receipt to installation, so you know which serial number went to which address. For a broader view of why serial-level tracking matters, see our guide to lot and serial tracking in ERP.
Refrigerant
Refrigerant is both inventory and a compliance record. Under 40 CFR 82.157(l), technicians servicing appliances with a full charge of 50 or more pounds of class I or class II refrigerant, such as R-22, must give the owner or operator documentation that includes the amount and type of refrigerant added, and these records must be kept for at least three years (eCFR, up to date as of October 5, 2026). If refrigerant is posted to the job as a quantity in pounds, your inventory system and your compliance record come from the same entry.
Cycle counts
A cycle count checks some items or locations on a schedule instead of counting everything once a year. A variance on a truck usually points to a part used but not posted, a counter purchase not entered, or a part moved between trucks without a transfer. Our article on how to improve inventory control covers counting discipline in more general terms.
Where HVAC inventory control usually breaks down
Technicians add labor to the invoice but not the small parts. Counter purchases are paid on a company card and never entered against a truck. Equipment is installed without the serial number being captured. The office counts once a year, writes off the difference, and never finds the cause.
The most important software decision is where quantities and costs live: in the field service platform, the accounting system, or an inventory add-on. Running quantities in two places almost always produces two different answers.
How field service platforms and accounting systems handle it
ServiceTitan
ServiceTitan offers two levels of inventory. Its truck replenishment feature collects the materials technicians add to invoices and turns them into purchase orders, organized either as one order per vendor or one order per truck. ServiceTitan states that this feature tracks what needs restocking in real time but does not track the on-hand quantity on each truck, and that truck replenishment cannot be used at the same time as QuickBooks inventory (ServiceTitan, updated July 10, 2026).
Its full inventory tools create replenishment records when a location falls below an item’s minimum reorder point, and refill trucks by warehouse transfer or purchase order, triggered only after a job starts (ServiceTitan, updated March 27, 2026). Cycle counts can be set for a single location or across many locations from a template (ServiceTitan, March 27, 2026).
With serialized inventory, technicians scan or select a serial number from truck stock in the mobile app, and each serialized item on an invoice creates an installed equipment record (ServiceTitan, updated April 9, 2026). The serialized configuration requires Technical Support to enable it and cannot be undone once activated (ServiceTitan, updated May 22, 2026). ServiceTitan does not publish prices and asks buyers to request a quote.
Simpro
Simpro’s feature page lists stock visibility by location, minimum stock alerts and maximum restock levels, automatic stock updates when purchase orders are received, barcode-based stocktakes and supplier catalogs that sync current pricing (Simpro, no date shown). It does not describe serial number tracking, so confirm that in a demo. Simpro does not publish pricing.
Housecall Pro
Housecall Pro’s help center does not describe built-in tracking of stock quantities. It recommends QuickBooks Online Plus for inventory tracking, handles materials as price book items that sync to QuickBooks Online, and offers material usage reports (Housecall Pro, January 21, 2026). Housecall Pro also lists Ply as an integration for truck and warehouse stock (Housecall Pro, January 20, 2026). Housecall Pro publishes plan pricing of $59, $149 and $299 per month billed annually for Basic, Essentials and Max, or $79, $189 and $329 billed monthly (Housecall Pro, checked October 7, 2026).
FieldEdge
FieldEdge lists inventory management across warehouses and trucks as part of its QuickBooks integration (FieldEdge, checked October 7, 2026, no date shown). FieldEdge customers can also add Ply for truck stock. Ply’s integration guide explains that Ply reads FieldEdge work orders, deducts materials from the warehouse or truck selected, and recommends setting up each truck as a location in Ply. It also states that purchasing is not part of the current integration, so part requests continue to run in FieldEdge (Ply, August 13, 2026). Ply sells this add-on.
Service Fusion
Service Fusion publishes three plans with unlimited users: Starter at $208 per month, Plus at $325 and Pro at $533, billed annually. Inventory management is included on Plus and Pro and is an add-on on Starter (Service Fusion, checked October 7, 2026, no date shown). Ask how purchase orders and equipment tracking work before you buy.
Dedicated inventory add-ons
Ply is an inventory add-on built for contractors with trucks. It lists integrations with ServiceTitan, Jobber, Housecall Pro, FieldEdge and ServiceM8 on all plans, with QuickBooks Online and Sage Intacct on its Plus plan, along with automated replenishment and three-way invoice matching. Ply prices by the number of stock locations, meaning trucks and warehouses, and does not publish dollar amounts (Ply, checked October 7, 2026, no date shown).
QuickBooks Online and other accounting systems
QuickBooks Online includes inventory tracking only on Plus and Advanced, which list at $140 and $340 per month before promotional discounts (Intuit, checked October 7, 2026, no date shown). It offers FIFO or moving average cost, defaults to FIFO if you create an inventory item before choosing, and does not allow the method to be changed later (Intuit, September 22, 2026). We did not find Intuit documentation for truck-level stock locations in QuickBooks Online, so verify this before relying on it. Larger commercial mechanical contractors often run an ERP alongside the field platform, which our guide to ERP for inventory management covers.
At-a-glance comparison
| Product | Truck and warehouse stock | Serialized equipment | Published pricing |
|---|---|---|---|
| ServiceTitan | Native: min reorder points, transfers, POs, cycle counts | Native; creates installed equipment records | No, quote only |
| Simpro | Native: stock by location, min and max levels, PO receipts, barcode stocktakes | Not described on feature page | No, quote only |
| Housecall Pro | QuickBooks Online Plus or Ply | Not documented for inventory | Yes, $59 to $329 per month |
| Service Fusion | Included on Plus and Pro; add-on on Starter | Not described on pricing page | Yes, $208 to $533 per month billed annually |
| FieldEdge with Ply | FieldEdge inventory runs with QuickBooks; Ply tracks trucks as locations | Confirm with vendors | Ply prices by stock location; no figures published |
| QuickBooks Online | Plus and Advanced only; FIFO or average cost | Not documented | Yes, $140 and $340 list |
Worked example: the cost of unposted parts
Illustration: the figures below are constructed for this guide and do not describe a real company. Consider a residential HVAC contractor with 12 trucks carrying $5,500 of stock each at cost, $140,000 in the warehouse, and $48,000 of parts used each month at cost.
Suppose 3% of parts used are never added to an invoice. That is $1,440 a month, or $17,280 a year at cost, neither billed nor charged to a job. Inventory stays overstated by the same amount, job margins look better than they are, and a year-end count writes off the whole amount in one period with no record of which jobs used the parts.
If the contractor counts each truck monthly instead, a count might show a $410 shortfall on one truck. Because it covers one month on one truck, the service manager can match the missing parts to that technician’s calls, bill some of them, and give specific feedback.
The underlying entries are simple. A purchase order receipt debits inventory and credits accounts payable. A transfer moves value between locations with no expense. A part posted to an invoice debits cost of goods sold for that job and credits inventory at the truck location.
Our independent take
If you already run ServiceTitan or Simpro, start by using the inventory tools you already have before buying an add-on, and decide early whether quantities live in the field platform or in QuickBooks, because ServiceTitan states its truck replenishment cannot run alongside QuickBooks inventory. If you run Housecall Pro, or FieldEdge without its QuickBooks inventory, an add-on such as Ply is a more direct fix for truck stock than switching platforms. In every case, posting discipline in the mobile app matters more than the product you buy.
Three buyer scenarios
Residential contractor, 8 trucks, running Housecall Pro. Trucks are restocked by eye and the office has no inventory figure it trusts. Set a standard truck list, then choose QuickBooks Online Plus for quantities and costs or an add-on such as Ply for truck-level locations. Start monthly truck counts immediately.
Residential and light commercial contractor, 35 trucks, running ServiceTitan. The company uses truck replenishment purchase orders but has no on-hand truck quantities. Move to ServiceTitan’s full inventory with truck locations, reorder points and transfers, and plan how QuickBooks inventory will change. Evaluate serialized inventory if warranty registration is a problem, knowing it cannot be turned off.
Commercial mechanical contractor, 60 trucks plus project work, running an ERP. Keep inventory valuation and purchasing in the ERP, and require the field platform to post parts usage and serial numbers back to it. Test that integration with real jobs before go-live.
When you do not need dedicated inventory software
A contractor with two or three trucks that buys most parts per job can usually manage with a standard truck list, supplier purchase history and a monthly count in a spreadsheet.
The tax rules may also allow simpler treatment for smaller businesses. For tax years beginning in 2026, a business meets the section 448(c) gross receipts test if its average annual gross receipts for the prior three years do not exceed $32,000,000 (IRS Rev. Proc. 2025-32, 2025). Businesses that meet the test may be able to use the simplified inventory methods in section 471(c). Ask your CPA how this applies, because tax treatment does not remove the need to control truck stock.
How we researched this
We read current documentation and pricing pages for ServiceTitan, Simpro, Housecall Pro, FieldEdge, Service Fusion, Ply and QuickBooks Online, plus the relevant EPA and IRS texts, and reviewed the vendor-published pages that rank for this topic. Where a vendor does not publish a price or document a capability, we say so. No vendor paid for inclusion.
Related guides
- Commercial HVAC Service Software: What Mechanical Contractors Need Beyond Residential Tools
- HVAC Flat Rate Pricing Software: How It Works and How to Choose
- Kitting in Inventory Management: How ERP and Inventory Software Handle Kits, Bundles and Assemblies
Frequently asked questions
How much stock should an HVAC service truck carry?
There is no standard dollar figure, because it depends on your call mix, equipment brands and distance to supply houses. Build the truck list from twelve months of parts usage, set a minimum and maximum for each item, and review it each season.
Does Housecall Pro have inventory management?
Housecall Pro’s help center does not describe built-in tracking of stock quantities. It suggests QuickBooks Online Plus for inventory tracking and lists Ply as an integration. Materials can still be added to jobs as price book items that sync to QuickBooks Online.
Can ServiceTitan track inventory on each truck?
Yes, with its full inventory tools, which support warehouse and truck locations, minimum reorder points, transfers, purchase orders and cycle counts. Its simpler truck replenishment feature builds purchase orders from materials used but does not track on-hand quantity on each truck, according to ServiceTitan’s documentation.
How often should HVAC contractors do cycle counts?
A common practice is to count every truck monthly and high-value warehouse items more often. Frequent counts keep each variance small enough to trace back to specific jobs, so investigate the cause before posting the adjustment.
Should inventory live in my field service software or in QuickBooks?
Choose one system as the source of quantities and costs and have the other receive summarized entries. Running quantities in both usually produces two different answers. ServiceTitan, for example, states that its truck replenishment feature cannot be used together with QuickBooks inventory.
Sources
- ServiceTitan, Truck inventory replenishment overview, updated July 10, 2026. help.servicetitan.com
- ServiceTitan, Replenish items using transfers, updated March 27, 2026. help.servicetitan.com
- ServiceTitan, Create cycle counts, March 27, 2026. help.servicetitan.com
- ServiceTitan, Get started with serialized inventory, updated May 22, 2026. help.servicetitan.com
- ServiceTitan, Add serialized items to invoices in the Field Mobile App, updated April 9, 2026. help.servicetitan.com
- ServiceTitan, Pricing page, checked October 7, 2026, no date shown. servicetitan.com
- Simpro, Track inventory feature page, checked October 7, 2026, no date shown (Simpro sells field service software). simprogroup.com
- Housecall Pro, Effective strategies for inventory tracking and reporting, January 21, 2026. help.housecallpro.com
- Housecall Pro, Pricing page, checked October 7, 2026. housecallpro.com
- Service Fusion, Pricing page, checked October 7, 2026, no date shown. servicefusion.com
- Housecall Pro, Ply Inventory Management integration overview, January 20, 2026. help.housecallpro.com
- FieldEdge, Field service software feature page, checked October 7, 2026, no date shown. fieldedge.com
- Ply, Using Ply inventory in your FieldEdge workflow, August 13, 2026 (Ply sells inventory software). help.getply.com
- Ply, Pricing page, checked October 7, 2026, no date shown. getply.com
- Intuit, QuickBooks pricing page, checked October 7, 2026, no date shown. quickbooks.intuit.com
- Intuit, What is FIFO and how is it used for inventory cost accounting, September 22, 2026. quickbooks.intuit.com
- US EPA, 40 CFR 82.157, Appliance maintenance and leak repair, eCFR up to date as of October 5, 2026. ecfr.gov
- IRS, Revenue Procedure 2025-32, inflation adjustments for tax years beginning in 2026, 2025. irs.gov