The short answer
A common target for an HVAC business is a cash reserve covering three to six months of operating expenses. The right number for you depends on how seasonal your revenue is and how long your customers take to pay. A reserve is what carries you through the slow shoulder seasons, a surprise equipment failure, or a stretch where commercial customers pay late. It is the difference between a stressful month and a missed payroll.
HVAC revenue is lumpy. Summer floods in, the shoulder seasons run thin, and a single broken-down work truck or slow-paying commercial account can throw off a whole month. A reserve smooths those bumps. Without one, every slow week becomes a crisis and every surprise becomes an emergency. With one, you make decisions from a position of calm instead of panic.
Start with your monthly operating expenses: payroll, rent, insurance, software, vehicle costs, and the rest of your overhead. Then multiply.
| Reserve level | Covers |
|---|---|
| 1 month of expenses | Bare minimum, little protection |
| 3 months of expenses | Solid baseline for most HVAC shops |
| 6 months of expenses | Strong protection, room to handle a real downturn |
If your monthly operating cost is, say, 40,000 dollars, a three-month reserve is 120,000 and a six-month reserve is 240,000. Those numbers can look large, which is exactly why you build them gradually, in the good months.
The trick is to fund the reserve when cash is flowing, in summer, not when it is tight in winter. Treat it like a fixed bill: move a set amount into a separate savings account every time a big job pays. Keep it out of your operating account so you are not tempted to spend it. A reserve you can see and reach too easily is a reserve that disappears. Build it slowly, protect it fiercely, and only touch it for what it is meant for.
| min |
| solid |
| strong |
How much cash should an HVAC business keep in reserve?
A common target is three to six months of operating expenses. More seasonal businesses, or those with slow-paying customers, should lean toward the higher end.
How do I calculate my cash reserve target?
Add up your monthly operating expenses, then multiply by the number of months of coverage you want, usually three to six.
When should I build my cash reserve?
During your busy, high-cash months. Funding the reserve in summer is what carries you through the lean shoulder seasons.
Jeremy Brewer is the founder of 911 Bookkeepers LLC in Baton Rouge, Louisiana. He came up through the HVAC trade and works as a licensed paramedic in EMS. He is a Xero Certified Advisor. 911 Bookkeepers is built for the trades.
Book a free 30-minute financial checkup and find out exactly where your business stands.