Load Compensation and Modulating Controls
Load compensation varies the boiler output based on how far the room is from its target rather than on the outside temperature.
Load compensation varies the boiler output based on how far the room is from its target rather than on the outside temperature. It needs no external sensor, which makes it the easier retrofit of the two compensation methods.
How it behaves
As the room approaches temperature the boiler throttles back instead of switching off, holding a steady, low flow temperature.
Short cycling is the enemy
A boiler that fires hard, hits target, stops, then repeats wears components and wastes fuel. Modulation is what stops that.
Protocol matters
OpenTherm or a manufacturer's own bus lets the stat and boiler negotiate. A simple on/off stat cannot do this however smart the app looks.
Questions we get asked
Is load compensation as good as weather compensation?
It is close in practice and much easier to retrofit. Some systems run both together.
Do I need to change my boiler?
Not necessarily. Many boilers already installed locally support modulating control that has never been wired up.
Will it make the house slower to warm?
Slightly gentler, yes, but with better temperature stability once it gets there.