If you know you’re going to need a furnace soon

and you are in snow country where going without a furnace is not an option, I’d go even farther. I’d make it part of the snowball and save it up as though it were your next debt.

Disclaimer: I’m in New England and it’s 8F right now. Going without a furnace is not an option in this part of the country; it’d be impossible to keep pipes from freezing without severe risk of burning the house down. When my furnace failed, it failed completely; repair was not an option. (the main barrel cracked,leaking CO)

If you’re someplace warm, maybe not so much.