What Is a Heater in Poker?

A heater is a stretch of sessions where everything lands: your sets flop, your bluffs go through, and the coolers all fall your way. It is a variance upswing rather than a change in your win rate, and it lasts exactly as long as it lasts. Every winning player runs into them, and most misread what they mean.

What a heater looks like

You open A♥K♥ from the CO, the BB defends, and the flop comes K♠K♦7♣. You get paid on three streets. Next orbit Q♣Q♠ holds against A♦K♦, and an hour later 8♠8♦ flops a set into an overpair. Nothing you did was wrong, but nothing you did produced those boards either.

Zoom out and the maths is unremarkable. Standard deviation in 6-max no-limit sits around 100bb per 100 hands, so across 10,000 hands the noise in your observed win rate is roughly 10bb/100. A genuine 3bb/100 winner showing 13bb/100 over a fortnight is one standard deviation from expectation. Common, not miraculous.

Heater or real improvement

The difference does not show up in the graph. It shows up in the decisions behind it: a heater flatters the same game you were playing last month, while improvement changes what you do in identifiable spots.

Signal	Heater	Real edge
Sample size	A few thousand hands	Tens of thousands
Where profit comes from	Showdowns you won	Thinner value, better folds
Survives a card change	No	Yes

Run the numbers before you conclude anything. The poker variance calculator shows the spread of results a given win rate produces over a given sample, and the width of that band is usually the whole answer.

What to do while it lasts

Do not move up because the graph told you to. A heater inflates your bankroll and your confidence at the same rate, and the confidence is the expensive half. Taking a shot at $2/$5 on the strength of 8,000 good hands means sitting down with borrowed evidence.

Do not widen your game either. The urge to press, opening 60% of hands from the CO because everything is working, turns a run of good cards into a leak that outlives the run. Keep the same ranges, bank the extra buy-ins, and expect the downswing on the other side to feel every bit as long and just as personal.