Answer first

Start from the commissioned curve. If the whole home is consistently too cool or warm across similar weather, make one small documented change and allow time for the building to respond. If one room is wrong, investigate that room or circuit before moving the whole curve.

Use modest schedules and setbacks rather than boiler-style bursts. Keep hot-water settings separate and understand when an immersion or boost is used.

One change

Adjust one setting at a time and record it

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Weather-led

Water temperature rises as outdoor temperature falls

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Room comfort

Judge results by stable room temperature, not radiator touch

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Understand the heating curve

The controller maps outdoor temperature to a target flow temperature. A steeper or higher curve sends hotter water, while a lower curve can improve efficiency if emitters still meet demand.

Names differ by manufacturer—curve, slope, shift or compensation—but the design principle is the same. Ask the installer to mark the commissioned values in the handover.

Diagnose whole-home and single-room problems differently

If all rooms track too cold in colder weather, the curve or design may need review. If only one room is cold, check radiator size, valve position, balancing, flow and local heat loss.

Raising the entire curve for one room overheats the rest and may increase bills. Fix the limiting room or circuit.

Use schedules and setbacks gently

A heat pump normally works efficiently by maintaining temperature with long, low-output runs. Deep overnight shutdown can create a high morning recovery demand and hotter water.

A small setback may suit some homes and tariffs. Heavy stone homes or underfloor systems respond slowly, so wait long enough to judge changes.

Keep hot water and boosts visible

Cylinder temperature, schedule, hygiene cycle and boost are separate from space-heating curve. A permanent boost or frequent immersion can add substantial direct-electric use.

Label normal and emergency controls for the household. If occupants do not know which button is temporary, an efficient design can be operated inefficiently.

What to read next

Related answers and services

Controls guideWork through curve, schedule and setback in depth.Run all day?Compare steady operation with deep setbacks.Higher electricity useTrace tariff, demand, controls and faults.All 60 heat-pump answersFind the next question in the FLO knowledge library.

Questions people also ask

What is the best heating curve?+

There is no universal value; it depends on heat loss, emitters, climate and target room temperatures.

Should thermostatic radiator valves be fully open?+

Follow the commissioned zoning and balancing plan; closing many emitters can reduce flow and change control behaviour.

How quickly should I judge a setting change?+

Allow the building and weather enough time to respond—often at least a day, and longer for heavy fabric or floors.

Evidence used for this answer

Figures are explained in context and links go to the independent source. Prices, tariffs, scheme rules and standards can change, so check the source again before making a financial or technical decision.