I'm starting to think that's a common thread here. I didn't realize oil boilers could last so long if they're well-maintained. I'd rather keep something that's going to last and my main point of contention is oil prices. But you're not the only one to mention looking into supplemental heating. I think I might aim for effective supplemental heating first before I throw out what works (and has worked for a bit longer than I've lived). Then I can take another look at prices in a year or three. Thank you for your advice.