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Essential Radiator Guide

An engineer's terminology can be slightly confusing! We've put together an essential radiator glossary to get you started with radiator DIY.

Air Vented Valves

  • An air vented valve is a device which automatically 'bleeds' the attached radiator by releasing trapped air. Air vented valves are non-essential accessories that fit on the bleed valve.


  • Aluminium panels are lightweight and extremely quick to warm up. The material produces a higher BTU so is a great option for large rooms.

Angled Radiator Valves

  • These are normal radiator valves with a 90-degree bend. This helps to connect a radiator to plumbing where an angled valve is needed - usually when pipework exits the wall or below floorboards.


  • BAR is a very common measurement of pressure.

Radiator Bleeding & Bleed Valves

  • Radiator bleeding is the process of releasing trapped air inside a radiator. Air must be released as it prevents hot water from reaching the top of the radiator, leaving cold spots. A radiator's bleed valve is found at the top of the radiator, and is a small metal square found inside a round nut. Here's our step-by-step guide on how to bleed a radiator.


  • A boiler is a sealed tank inside a home that heats water to be distributed throughout the home through pressurised plumbing.


  • BTU basically means heat, and is the industry measurement to compare heat outputs. Every room has a BTU requirement - check out our BTU calculator to ensure you choose the right heating for the size of your room.

Cast Iron

  • This material is affordable, durable and gives a lovely traditional finish. Cast iron is great for holding heat for a long time, however it does take longer to warm up.

Central Heating

  • Central heating refers to the common home-heating system in which hot water is heated in a 'central' boiler. It's then circulated through radiators.

Combination (Combi) Boiler

  • A combi (or combination) boiler supplies an instant hot water output and supplies a home's central heating as well.

Convector Radiators

  • These are normal radiators with convector fins which increase the BTU.

Convector Fins

  • Convector fins are long sheets of metal which are bent into a zig-zag shape and then welded to the rear of a radiator panel. This increases the surface area of a radiator.


  • Corrosion in radiators refers to the inevitable build up of particles from the water, along with rust from both inside the radiator and the system in general. Erosion happens to even the most rust-resistant systems.

Designer Radiator

  • Designer radiators are made to incorporate interesting and non-standard designs which may not necessarily affect performance. They're usually chosen for their visual impact, as well as their ability to heat a room.

Double Panel Convector Radiators

  • One of the most popular radiators are the humble double panel convector radiator. These have a layer of convector fins sandwiched between the radiator panels, and have a high heat output whilst being simple to maintain. 

Dual Fuel

  • Dual fuel is when towel rails and radiators can heat up as part of the central heating system through gas, as well as independently through electric.


  • Efficiency refers to the performance of a radiator. Basically, how good it is at using your gas or electric to heat a room.

Heated Towel Rail

  • A heated towel rail is a smaller, low power radiator designed to hold and warm towels.

IP Rating

  •  IP stands for Ingress Protection and is an international classification system that rates the degree of sealing effectiveness of electrical enclosures against intrusion from items such as dirt, dust and especially water. 

Manual Valves

  • A manual valve is the basic form of a radiator valve. It's essentially a tap which controls the flow of water into the radiator which affects how hot the radiator gets.

Pipe Centres

  • Pipe centres are the overall distance between the 'tappings' on a radiator.

Steel or Mild Steel

  • Steel is affordable and relatively light. Its major selling point is its ability to be easily shaped and mass produced, making it the perfect option for affordable designer radiators.

Stainless Steel

  • Stainless steel radiators are built to last and are excellent heat conductors, keeping your room warm for a long time even after they have been turned off. The material is also anti-corrosive, impact resistant and durable. 


  • Tails are the copper pipes fitted to a radiator for plumbing installation.


  • Tappings are the thread inside the inlets of a radiator, where the valves (or elements) are screwed.

Thermostatic Valves

  • A thermostatic valve is a type of valve that adjusts itself to the temperature of the room. They aren't usually too complex - most have a tiny bit of wax inside them that regulates room temperature.

Underfloor Heating

  • Underfloor heating refers to home heating solutions that are installed out of sight, beneath the floor. It's usually installed in bathrooms, but it can heat an entire room with the right coverage. Our guide on all things underfloor heating explains all.


  • A radiator valve sits at either side of a home radiator to connect it to the central heating system. It also controls the temperature output by managing the flow of water in and out of the radiator.

Variable Heat

  • This refers to the way that temperature can be manually controlled.


  • Watts is another way of measuring heat output, and is only really used when referring to electric radiators.


  • A zone, in the context of heating, is any area within a building that is to be heated. Alternatively, zone can also mean an area inside a room which requires a different IP rating requirement due to moisture - for example bathrooms.

We hope this list of technical heating terms has given you some insight into the wonderful world of radiators. If you have any further questions, feel free to visit our FAQs page  or get in touch with our team via live chat.

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