My parents bought heat pumps for their living room and den which are on the same level in 2021. My dad says their furnace rarely kicks on and only primarily heats the upstairs of their 2400 sq feet-ish home or if it's super cold, like below zero cold, but that's just to help supplement the heat pumps because they're working hard to keep temp in below zero cold.

He used a DIY kit called Mr Cool and did the installation himself. He has a lot of mechanical and DIY experience. He said he wished he'd put one unit upstairs and one downstairs because one unit handles the entire downstairs and having two on the same floor is overload. He doesn't regret the switch at all.

We plan to switch to a heat pump in the house my husband and I are in for the same reason, oil is too damn expensive and the added bonus of a heat pump is they are an A/C in the summer an d our summers have been getting more and more hot and humid each summer. Best of luck to you!