Buying the right radiator for my home - Consumer guide

Look for the MARC logo or ask for an independent test certificate for a test that has been done by an accredited body (see detail below).

Buying radiators, the facts

The most crucial element when considering the purchase of a new radiator is the output of the product. The radiator has one job, to provide you with the necessary heat you require for the space you are heating.

For hydronic radiators, which go onto a water based central heating system, there are a few simple factors which govern output; The temperature of the water when it leaves the boiler/heat source (known as the flow temperature) and the total surface area and amount of material contained within the product that will heat up, and therefore, “radiate”.

When the flow temperature of the water differs from system to system, how can we be sure the claims of output are accurate?

The Government has created a level playing field, on which all manufacturers, and resellers, must compete. This has been enshrined in UK and EU law.

Note: The below article references the “CE” mark. Since leaving the EU, this has been replaced with the “UKCA” mark. However, the CE mark can still be used on Radiators until the end of 2022. This article will be updated at that point. will always comply with whatever legislation is in place.

It is the LAW that radiators and convectors installed in heating systems in buildings conform to the European Standard BS-EN442. Products that conform will have a 'UKCA'/ ‘CE’ mark.

What is EN442?

Simply put it is a test that measures outputs based on set parameters, this ensures all radiators are measured equally on the basis of a water flow temperature of 80O .The full calculation assumes a desired room temperature and the temperature of the water as it returns to the heat source, it can then work out how much heat the radiator has supplied. You should see that all outputs are measured according to EN442 standards using these parameters, which is referred to as Delta (often shown using this symbol Δ) t50.   

By placing the UKCA/CE marking on a product a manufacturer is declaring, on his sole responsibility, conformity with all of the legal requirements to achieve UKCA/CE marking. The manufacturer is thus ensuring validity for that product to be sold throughout the European Economic Area, including the UK.

This legislation is designed to ensure heating engineers, and consumers alike can fairly compare the heat outputs of one radiator against another, so that they can choose the right fit for their home.

ALL products MUST be independently tested BY LAW in a special testing laboratory, known as a “notified body”.

What do I need to know?

Unfortunately, there are some companies out there who incorrectly “claim” legislation compliance for the radiators they are selling, either through ignorance, or deliberate deception. Some quote outputs based on higher Delta t results (Delta t60 or even 75) these will show higher outputs, which assumes system temperatures that may not reflect the actual performance of your system and should not be directly compared to results based on Delta t50 parameters.

This leaves you potentially specifying radiators for projects that may not be suitable for the rooms they are planned for, subsequently leaving you cold and out of pocket, as you will need to turn the heating up to get the desired room temperature.

What to look out for

Many brands place a UKCA/CE mark on their products, claiming that the products are safe for the end-customer, and sell them within the EU zone and the UK. But that is not always the case. Sometimes the CE mark you can see on a product can be fake.

There are some test certificates on the market that may seem genuine but are not fit for purpose.

How do I know if a product is genuine?

Any product with UKCA/CE should have a declaration of performance, which may be paper, on the packaging or via a website. This should include various pieces of information amongst which is the “notified body’s” (testing laboratory’s) 4 digit number.

A notified body is an organisation that has been designated to assess the conformity of certain products, before being placed on the market, with the applicable essential technical requirements.

This leaves you potentially buying radiators for a project that may not be suitable for the rooms they are planned for, subsequently leaving you cold and out of pocket as you will have to turn the heating up to get the desired room temperature.

Current notified bodies for Radiators are;

Notified body No. Name of notified body - Address Contact
Old Bracknell lane West, Bracknell, Berkshire, RH12 7AH, UK
+44(0) 1334 465 600
0626 Institut für Gebäudeenergetik (IGE) - Lab. HLK
Pfaffenwaldring 6, 70569 Stuttgart, Germany
+49(0) 711 685 62085
1623 Cetiat - Technical Center Industries Aérauliques Et Thermiques
La DOUA - 25 Avenue des Arts, 69100 Villeurbanne, France
+33(0) 4 72 44 49 00
1695 Politecnico di Milano - DIP. Energia - Lab. M.R.T.
Via Lambruschini, 4, 20156 Milano MI, Italy
+39(0) 2 2399 3834
+39(0) 2 2399 3825
0407 Istituto Giordano spa
Via Gioacchino Rossini, 2, 47814 Bellaria RN, Italy
+39 0541 343030
1428 WSPLAB, DR. ING. Harald Bitter
Kapuzinerweg 7, 70374 Stuttgart, Germany 
+49(0) 711 953 922-0
1015 SZU - Strojírenský zkušební ústav
 Hudcova 424/56B, CZ-621 00 - Brno- Czech Republic
+420 541 120 111
2693 Heatest, s.r.o.
Cp. 84 Býkev, 276 01 Melnnik, Czech Republic
+420 737 284 443


Who is responsible?

It is ALL RESELLERS legal responsibility to ensure all products conform. A Reseller could be a heating engineer or a heating merchant/supplies shop. In this case, are the reseller.

The are proud of our products’ MARC affiliation, and, as most of our products are of Italian design and manufacture, use Politecnico De Milano for all our testing.

Unfortunately, there are many products on the market that have either not been tested or have been tested in Laboratories that are NOT official “notified bodies”, and as such, they are NOT compliant with the law. Consumers risk being sold products that are not fit for purpose.

If you challenge a seller of radiators – and you should ask for test certificates, and if the reseller makes comments such as “it doesn’t matter”, or “it is still a valid test certificate”, or even “nobody police’s it”, then buyer beware. You will probably end up with a product that is not fit for purpose.

Do EU rules still apply?

After our separation from the EU, the legislation remains the same. It is simply written into UK law. Irrespective of our removal from the EU.

Consumer protection remains a top priority for the government.

Cost of a non genuine product

  1. It will not adequately heat the space it was purchased to do
  2. In order to heat the room, it will be necessary to run the boiler at higher temperatures than would have been necessary
  3. This will burn more fuel and in turn create more CO2 emissions
  4. Burning more fuel will increase heating cost
  5. This may affect the life cycle of the boiler or heat source

Protecting consumers

But, given so many products out there “flout” the law, what can I do to ensure the product I am buying is above board and complies?

Our advice? Look out for MARC membership! All members of MARC must provide proof of product performance (UKCA / CE marking), together with test certificates from a “notified body” as part of our membership criteria.

MARC members are committed to being at the forefront of change. Members are proud of their brand and what it stands for. we aim to work with every business involved in the manufacturing and supply chain of radiator and convector products.

For more information about MARC please visit