I think you just mean different things by "heating" - if you're talking about heating in a closed system, they're the same - 5 joules of energy are needed to in

I think you just mean different things by "heating" - if you're talking about heating in a closed system, they're the same - 5 joules of energy are needed to increase the total heat energy by 5 joules, with either approach. The advantage of the heat pump is that we are, for, say, 3 joules of energy, heating part of the system by 5 joules and heating the other part of the system by -2 joules. This is great for home heating and the like because we don't care about making the outside slightly colder.