How to Track HVAC Maintenance Agreements in a Spreadsheet (Free Column Setup)

Yes, we sell software that replaces this spreadsheet. We're going to show you how to build the spreadsheet anyway, because if you have 20 agreement customers, a well-built sheet is genuinely all you need — and a badly built one is how tune-ups get missed. Steal this structure; upgrade when it starts hurting.

The columns that matter

One row per customer. Set up these columns in Excel or Google Sheets:

The one formula you need

In a "Status" column, flag anyone due within 30 days or overdue. In Google Sheets, with next due date in column H:

The weekly routine that makes it work

1. 1Monday: sort by next due date. Email or call everyone red/yellow.
2. 2Log the date in "Last reminder sent" the moment you send it.
3. 3When a visit is completed, update "Last service date" and recalculate "Next due date" (add 6 or 12 months per the plan).
4. 4First Monday of the month: check the "Agreement expires" column for anything within 60 days and send renewal notices.

Total time: maybe an hour a week at 30 customers. Do it every single week and this system genuinely works.

Where spreadsheets break

Every shop we've talked to hits the same failure points as the list grows:

• The update discipline decays. One busy July week you skip the Monday routine. Now the "next due" dates are stale and you don't trust the sheet anymore.
• Reminders are still manual. The sheet tells you who's due; you still have to write and send 25 individual emails. That's the part that gets skipped.
• No one else can use it. The sheet lives in your head and your Google account. A tech in the field can't see equipment notes; your spouse can't cover for you.
• Formulas silently break. Someone sorts wrong, a row gets pasted over a formula, and customer #47 quietly stops appearing in the due list. You find out when they cancel.

The rule of thumb we've seen: spreadsheets work up to roughly 30–50 agreements. Past that, the weekly hour becomes three, the misses start, and each missed visit is a couple hundred dollars plus a renewal at risk.

What the upgrade looks like

AirTrack is essentially this spreadsheet with the manual parts removed: import your existing sheet as a CSV, and due dates calculate themselves when you mark a job done, reminder emails write and send themselves (personalized with the customer's name and equipment), renewals get flagged automatically, and your techs see their assigned jobs on their own phones — without seeing your revenue numbers.