Tesla opened orders for its solar roof on Wednesday, and the price of the roof is competitive with replacing the roof on your house. Replacing your roof is still expensive, and even the $21.85 price tag might feel like too much upfront, even with the 30 percent tax credit. But there’s a way to shave the cost down if you need to.

In most states, you can save $7,000 from the upfront cost of the roof by dropping the battery and selling the energy generated by your solar cells back to the electricity company. Depending on your energy use habits, this might not save as much money as the battery option in the long run, but this can help if you want a solar roof and need to pinch some pennies right now. And once you’ve gotten it installed and have settled your finances a bit, you can always add a battery later.

Getting a Powerwall battery with your solar roof means that you can store the energy you gather during the day so you can use it later. Tesla recommends it so that you have power if the electrical grid goes out, and being able to pull from your battery at night means you buy less electricity from the power company.

However, in every state except South Dakota, Tennessee, Alabama, Mississippi, and specific utility companies in Idaho and Texas, you can sell your solar energy to your electric company. This process is called net metering. It roughly means that when you produce solar energy, you get a credit on your electric bill. Then when you start using grid energy when the sun goes down, you use your solar credit first.

Some states will pay a little more for solar energy than the cost of grid energy, to incentivize people to get solar, which can add a little more financial help early on. And since it decreases the cost of the roof without changing the amount of energy you can get from your solar panels, not getting the battery could increase how much you make back from the roof, along with saving the $7,000 upfront.

Net metering makes some researchers worried that it will cause energy companies to increase costs for non-solar customers. So as solar becomes more popular, it’s possible the incentives for selling solar may decrease. But by then, you might be ready to add that Powerwall battery anyway.

Photos via Tesla