Your utility bills likely make up a significant part of your monthly budget, so it’s important to keep a close eye on them. But while your rent or mortgage stays the same month to month, your utilities don’t.

Sweltering summer days and icy winter nights can lead to budget-blowing spikes in your utility bills, and no matter how hard you try to budget and plan, you can’t predict the total each month. Or can you?

Budget billing may offer the consistency you crave. Here, personal finance experts describe how budget billing works and explain who may benefit from it, empowering you to answer this question for yourself: Does budget billing save money?

What is budget billing? It's a service that averages your monthly utility charges to determine a set amount to pay each month.

What is budget billing and how does it work?

As you consider this option, your first question might be: What is budget billing? Budget billing is a service offered by some utility companies that provides a set monthly bill for services like gas or electricity.

How does budget billing work? To calculate your monthly budget billing amount, a utility company will look at your past usage, typically over the last year, and average it to determine your monthly charge, says Sara Rathner, financial author and credit cards expert at NerdWallet. This will give you a predictable bill to pay each month, rather than one that fluctuates.

Keep in mind that if you recently moved into your home, the charges used to calculate your budget billing amount may be based on the previous owners’ or renters’ usage, says Rathner. Your actual usage may end up being more or less than theirs.

Another point to remember on how budget billing works: While budget billing gives you a steady amount to pay each month, this amount can, and likely will, change over time. Some providers update bill amounts quarterly, some annually. There’s no universal timeline for these updates, so be sure to ask your utility provider about its specific process, says Lance Cothern, CPA and founder of personal finance blog Money Manifesto.

How does budget billing work? Utility companies determine the monthly charge by averaging your usage over the past year.

These changes are made to capture your actual usage, whether that usage has decreased (a mild summer allowed you to keep the AC off more often) or increased (a brutally cold winter forced you to blast the heat). Typically, you will be notified in advance of the change.

Now that you know how budget billing works, you may be wondering: Could it save me cash?

Does budget billing save money?

Not exactly.

“Budget billing won’t save you money; it just evens your bill out over time,” Cothern says.

How does budget billing work if you end up using less energy and overpay? You may be reimbursed for the amount you paid above your actual energy usage, or the amount overpaid will be applied to next year.