How to improve students' understanding of energy transformation and conservation remains one of the main challenges of energy teaching. To address this challenge, we developed a new teaching strategy suited to high school based on history and philosophy of science (HPS). It involves five key ingredients: study and reproduction of Joule's paddle-wheel experiment, introduction of Rankine's definition, study of a historical text of Joule, use of an "ID card of energy," and early introduction and multiple application of the principle of energy conservation. This strategy was built and implemented in the frame of a collaborative and iterative work involving researchers and teachers. We examined the effects of this HPS-based teaching strategy on students' understanding of energy. We used a quantitative method based on pre- and post-tests (N = 95/87) completed by a qualitative analysis using both video recordings of classroom activities and videos produced by students during one of the teaching sequences. The outcomes show that the teaching strategy had an overall positive impact on students' learning of energy: in particular, Joule's paddle-wheel experiment seems to favor their understanding of the notion of energy transformation, while the early introduction and multiple application of the conservation principle appears as a relevant option to facilitate its mastering. This study illustrates how HPS might actually be introduced in classrooms and brings to light its usefulness for building new science teaching strategies.