Oil: 117,700 BTU/gal delivered (85% seasonal). COP values are at maximum capacity (worst case). Linear interpolation between the 5, 17 and 47°F points; below 5°F is extrapolated. Defrost and capacity loss are not modeled.
Each line shows the outdoor temperature at which the minisplit and oil cost the same to produce the same heat, for a given electricity price. When it's warmer than the line, the minisplit is cheaper; when it's colder, oil is cheaper. The solid line uses your oil price from the slider above, and the dotted and dashed lines show oil $0.50 lower and $0.50 higher. A line that runs along the top means the minisplit wins at every temperature shown, and one along the bottom means oil wins at every temperature shown.