Why is the home energy credit tax break tool not pulling up 30% of what I spent on "Furnaces powered by natural gas, propane or oil" when I file?

I spent $4850 for a new natural gas furnace in 2023. I was hoping to get $600 back [the max for line 24b on form 5695], but it's only pulling up a $150 tax break. What could be causing that?