HVAC has a cash-flow problem no other residential trade has quite as badly. On a system replacement you might pay several thousand dollars for equipment days before you install it, then wait for the customer to pay after it is running. For a stretch of days, you are financing a homeowner's comfort out of your own account.
That is the whole case for deposits. Not distrust, not aggressiveness, just the reality that a small HVAC company cannot carry equipment cost on behalf of every customer and stay solvent through a busy install season.
Not every job needs one. Asking for money up front on a two-hundred-dollar capacitor swap makes you look strange and slows the booking down for no benefit. The dividing line is simple: does this job require you to spend real money before you get paid?
The honest anchor is your own exposure, not a percentage somebody quoted you at a trade show. Work from what you are actually out of pocket before the job is finished:
Percentages get quoted a lot in the trades, and a deposit somewhere around a third to half of the total is a familiar structure on replacements. But the percentage is a communication shortcut, not the logic. If equipment is sixty percent of a job, a twenty percent deposit still leaves you financing the customer. Start from cost, then express it as whatever number is easiest to say.
One legal note worth checking: a few states regulate how much a contractor may collect up front on residential work, and some cap it by percentage or dollar amount. That varies by jurisdiction, so confirm your state's rule rather than assuming a number is safe everywhere.
On a multi-day install, a single deposit and a final payment leaves a long gap where your labor and material spend keeps climbing with nothing coming in. Milestones close that gap and, done well, they also give the customer a sense of progress.
A structure that works on larger HVAC projects:
Tie each milestone to something the customer can see happen. "Due when the new condenser and air handler are on site" is a fact they can verify from their driveway. "Due on day three" is arbitrary and invites argument. Milestones anchored to visible progress almost never get disputed.
Most of the resistance to deposits is not the customer's, it is the owner's. Plenty of HVAC owners never ask because it feels like accusing someone of not paying. So they eat the float, and they eat the occasional total loss.
The fix is framing. Do not present the deposit as protection against them. Present it as what secures their equipment and their date:
"The deposit covers your equipment. Once that's in, I order the unit and we're locked in for Thursday. The balance is due when it's running and you're happy with it."
That sentence does three things: it explains what the money buys, it gives them something in return (their install date), and it reassures them that the bulk is contingent on the work being done right. Almost nobody argues with it. The owners who get pushback are usually the ones who sounded uncertain asking.
Say it at the estimate, not on install day. A deposit introduced at approval is a term. A deposit introduced after they have committed is a surprise, and surprises about money damage trust.
Every deposit and milestone should appear on the written estimate before the customer approves it. Amount, what triggers it, and what the balance is. If they approve the estimate, they approved the payment structure, which means there is no separate awkward conversation later.
This is also where you protect yourself on the equipment itself. If a customer cancels after you have ordered a non-stock unit, whether the deposit is refundable should be written down, not improvised while emotions are running. Keep it simple and fair: refundable before the equipment is ordered, applied to restocking or non-refundable after. Customers accept clear rules; they resent invented ones.
The fastest way to lose the benefit of a deposit is to make collecting it a chore. If the customer has to write a check and mail it, or you have to remember to chase it, you have added a task to your week and a delay to your order.
Collect it the moment they say yes, while the enthusiasm is fresh. A deposit paid by card from the estimate approval screen arrives before you have left their driveway. That is when you order the equipment, and the job is genuinely underway instead of pending.
This is exactly what FieldForge handles: your estimate can carry a deposit amount, the customer approves and pays it by card in the same tap, and the balance bills automatically when the job is done. On staged jobs, progress payments each get their own pay link as you hit the milestone. No chasing, no separate invoicing, no gap between yes and money in the account.
Every HVAC owner has a story about the replacement that took months to collect, or the customer who went quiet after the system was running. Those losses do not just cost the ticket. They cost the equipment you already paid for, which means one bad job can wipe out the margin from several good ones.
Deposits are not about expecting the worst. They are about not letting a single customer's decision put your season at risk. Ask at the estimate, in plain language, every time, and it stops being a conversation at all. For the pricing that sits underneath all of it, how to estimate HVAC jobs covers the math, and what to charge for a service call handles the visit itself.