DIY Radiator Balancing Companion

Perfect Heat Balance. Optimize Your Central Heating

Unbalanced heating causes rooms close to the boiler to overheat while distant rooms stay freezing cold. Save up to 15% on energy bills by balancing your radiators step-by-step.

System Optimization Roadmap
House Balancing Progress
Round 2 Stabilization
Boiler Delta T Target
20.0°C Condensing
Stabilized Radiators
5 / 6 Optimized
Estimated Fuel Saving
~12.4% Calculated
Living Room Radiator (Steel Panel) ΔT: 19.8°C (Perfect)
Kitchen Radiator (Cast Iron) ΔT: 14.5°C → Close 1/4 Turn

How LockShield Optimizes Your System

Scientific hydronic balancing simplified for DIYers.

Boiler & Heat Pump Presets

Select your heat generator to auto-configure optimal Delta T targets. Targets range from 11°C for standard gas boilers, 20°C to maximize fuel condensing, down to 6°C for high-COP heat pump operation.

Ordered Radiator Mapping

Map your radiators room-by-room in order of piping distance from the pump. Enter quick pipe flow/return surface temperatures with a simple contact or infrared thermometer.

Non-Linear Turn Calculator

Standard lockshield valves are highly non-linear (a fraction of a turn near closed changes flow immensely). Our algorithm computes the exact turns (e.g. close by 1/8 turn) to reach balance smoothly.

Interactive Central Heating Simulator

Adjust the virtual lockshield valve below to see how flow rate and Delta T change. Find the perfect setting for each heating source to balance the system!

Hydronic Diagram Flow Speed: 1.2 L/min
IN 55°C OUT 35°C
IN: Inlet Flow (Hot) OUT: Outlet Return (Balanced)

Simulator Control Panel

2.00 turns
Closed (0) Optimal Fully Open (4)
CALCULATING STATUS
Target Delta-T: 20.0°C
Measured Delta-T: 20.0°C
Feedback:

Adjust the slider to simulate balancing. Target Delta T varies per heating device.

Thermal Physics & Guidelines

Central heating balancing relies on controlling the mass flow rate of water through each radiator. Adjusting the lockshield valve limits the flow, ensuring hot water is distributed evenly throughout the entire house.

  • The Delta T (ΔT) Rule: A higher delta T indicates slow flow and high heat extraction. A lower delta T indicates excessive speed (short-circuiting).
  • Boiler Condensation Target: To achieve condensing efficiency (fuel savings up to 15%), the return temperature must drop below 55°C. An unbalanced system returns hot water, shutting off the condensing phase.
  • Non-Linear Flow Characteristics: Most lockshield valves are highly restrictive near closing. The first 1/2 turn from closed controls 80% of the flow capacity. Precision is key.

Heating Source Target Guidelines

Standard Gas/Oil Boiler ΔT: 10°C - 12°C

Classic non-condensing heaters work best with standard flow ratios, keeping temperatures warm and balanced across all radiator elements.

Condensing Boiler ΔT: 15°C - 20°C

Requires low return temperatures (below 55°C) to allow steam in exhaust flue gas to condense, releasing latent heat back into system.

Heat Pump (COP Optimization) ΔT: 5°C - 8°C

Requires high flow rates and tight delta-Ts to maximize the Coefficient of Performance (COP) and maintain compressor health.