Energy altitude & the stick thermal: total-energy vario

A glider has two kinds of energy: altitude (potential) and speed (kinetic). Energy altitude combines them into one number:

Energy altitude = h + v²/2g

That is: "if I converted all my speed into height, how high would I reach?"

The stick-thermal problem

A normal vario only shows the rate of altitude change (dh/dt). Pull the brakes or slow down and you trade speed for height — the vario beeps "thermal!" but you gained no energy. This is the *stick thermal*: a false climb from a control input.

Total-energy vario

A total-energy (TE) vario shows the rate of change of energy altitude instead of height. Pitch up and altitude rises while speed drops → total energy is constant → TE vario reads ~0. It only beeps when the air actually lifts you.

Difference from net vario

Both aim at "what the air did", but they are different corrections:

• [Net vario](/blog/en/what-is-net-vario) adds the wing's polar sink back — useful while circling.
• Energy vario corrects for speed changes — useful on glides and pitch-ups.

A good real-time vario does TE compensation; in post-flight analysis, net vario reveals thermal strength while energy altitude helps you understand transition efficiency.

Where in Variograph

On the advanced analysis page you can follow energy altitude alongside raw altitude in the glide and altitude charts, and the visual analysis view shows the same transition's speed-for-height trade on the graph. Upload your own file from the dashboard to try it.