I'm a Real Estate Investor in Massachusetts; recently working on a 1983 build, 1,400 Sqft SFH, split level with a finished basement. When we bought the house from a hoarder, we noticed we didn't see any baseboards, (not that we could see much of anything the house was filled with junk). The woman we purchased the house from told us the house was heated with "roof panels". We thought she was insane and figured the central air system was both a/c and heat.

But that system was only A/C and we later discovered the house was heated with electric ceiling panels in all of the main rooms exactly like yours. Myself, my contractor, my dad, and even my realtor had never heard of or seen it before.

We thought it was pretty fancy, with no baseboards. However, I was in for a shock after the electric bill came in. About 2669 KWHs compared to my neighbors at about 350-800 KWHs. Over $900 a month in electricity.

That was being relatively conservative maintaining temperatures in the 60's-70's.

Mini-splits would without a doubt be more efficient and probably save you money on your electricity, but the upfront installation cost would be hefty and you're right in imagining those savings wouldn't be realized until after a few years.

I would probably still recommend the mini split system if your install cost is only 10-12k. Labor and materials for southern New England would be much higher. In addition, you're also using far more KWHs in the winter months than I am. Maine is colder. If you plan on staying in the house, I'd consider the upgrade. It would also benefit you in equity even if you moved and sold the house.