Frequently Asked Questions

Can private individuals or companies buy Hudevad products direct?

Yes, you are able to buy our products directly in our webshop on or buy contacting our sales office via mail: or phone.

For the UK please use Tel.: +44 (0) 2476 88 1200

For Denmark and continental Europe please use Tel.: +45 75 42 02 55

How to choose a radiator?

There are two important aspects when choosing a radiator: the type of radiator and the size of the radiator.

Types: There are many types of radiators to suit individual styles and needs, from low ones (LOWLINE) to high ones (VERTICAL) and flat ones (HORIZONTAL) to columned ones (CLASSIC).

For example, flat, horizontal radiators are used in all manner of rooms and are often positioned carefully beneath windows. Vertical radiators however suit rooms with high ceilings and limited wall space, and are often placed next to windows, doors or in a recess. Luckily, Hudevad has a range of styles to help with that. Browse through our GALLERY to see what suits you.


Sizing of radiators: Once you know the types of radiators you are interested in, you can use our handy Hudevad Output Tables (also known as Conversion Tables) to find the size of radiator(s) which emits the required heat output for your space. These are available under our DOWNLOADS section.

To use the Output Tables you will need to know your water flow and return temperature sets, which depends on what type of heating system you have. You will also need to have an idea of the amount of heat output required (usually expressed in BTU/h or Watts).

For a general overview on heat requirements, see the section on “What radiator output do I need for my sitting room?”. Nonetheless, Hudevad always advises you talk to your plumber or an HVAC specialist if you do not know your heat output requirements.

What radiator output do I need for my sitting room?

The required radiator output is determined by a number of parameters, including:

- The size of your sitting room.
- The age of your house (sitting room).
- Whether the house (sitting room) has been insulated since it was built (ceiling, walls, floor).
- Whether new energy-saving windows have been fitted.

As a rule of thumb usually somewhere between 30 and 100 W/m2 is required ñ see the examples below. Please note that the data used in the examples is for guidance purposes only!! For more exact calculations, please contact a consultant or a heating engineer.

Example 1:
Houses from the 1960s which have not been insulated since being built:
Required heat approx. 100 W/m2 floor.

Example 2:
Houses from the 1970s or 1980s which have been insulated since being built:
Required heat 50-60 W/m2 floor.

Example 3:
New houses:
Required heat 25-30 W/m2 floor.
Please note: Hudevad A/S does not perform heat loss calculations.

What is the delivery time for a Hudevad radiator?

All Hudevad radiators are made to order, which means that once you have ordered your radiator(s), our production will begin the production of your radiator(s). Our delivery time is 8-10 weeks on radiators in white and can be up to 12-14 weeks on colored radiators.


What do Hudevad radiators cost?

You will be able to find prices on each product sold online in our webshop.

(Please note: Professional buyers should contact our sales department for quotes on projects.)

In which sizes are your radiators available?

Hudevad has a large selection of differnt radiators in many sizes to accommodate most needs. All radiator types and dimensions can be seen in the shop or on the individual datasheets on the homepage. If you need something out of the ordinary please contact us per mail or phone. 

Can feet be installed on all Hudevad radiators?

Most of our radiators also have a solution with feet and on our core Hudevad Lowline products (Integral, P5, Fionia  Plan and SC), where feet is often sought after, we have made it easy for you to choose the option where feet is included.

On our other radiator model you will have to add the feet to your order. All avaiable feet and support legs can be found under accessories and then choose FEET. In the product discription you will find the number of feet needed for the different lengths of the radiator. 


My radiator is making noises - what can I do ?

Noises in and from the radiator and heating system.


Splash and blop sounds

Accumulations of air in the radiator are showstopper when the heat needs to be circulated in the system. Air in the radiator can typically be identified if one end of the radiator is hot while the other end is cold. The cold end probably has an air pocket somewhere. Another sign of air in the radiator may be that the radiator is making splash and blop noises.

When the radiator is to be vented, turn the vent valve counterclockwise. Remember to have a cloth or tea towel ready. If air comes out first, wait a moment and leave the valve open until water comes out. When water starts to come out, the radiator is vented and the valve can be closed again by turning it clockwise. If no water comes out, fill the heating system with water.
Remember to restart the circulation pump after venting.


Hissing in the pipes

The problem can be remedied by turning down the circulation pump speed. You do this on the pump itself. Older models run at excessive speeds, which is not necessary at all in smaller homes. New circulation pumps run at a lower speed and many can regulate the speed themselves according to the needs of the system.


Knocking sounds


It knocks fast and can sound like a machine gun!

This type of knocking noise often occurs if the return flow is reversed or if the radiator valve is reversed and installed incorrectly. The water therefore runs the wrong way through the radiator valve and it can not close properly. The water flow causes it to open and close very quickly, which sounds like shots from a machine gun.


It knocks and clicks slowly.

When iron and steel get hot, it expands. It could also be because the radiator expands in the brackets its mounted on. If the sound originates from the brackets, our experience is that knocking and clicking sounds occur because the small plastic protectors on the brackets are missing and have not been installed. As soon as they are installed, the knocking and clicking noices will stop.  

Knocking noises can also occur if the heating pipes are in tension or rubbing up against something - e.g. in a floor separation. As an experiment, you can remedy this by giving the pipes a little more space. If they are uninsulated, you can advantageously try to insulate them to attenuate the sound and the frictional resistance. If the problem persists, professional help must be called.

In which colours are Hudevad radiators available?

The Hudevad standard colour is RAL 9016 white for our radiators and RAL 7022 for Hudevad Integral Bench.

To see our colour collections, please consult our COLOUR BROCHURE. All our radiators are available in other standard RAL colours against a surcharge.

What do I do if my radiator becomes scratched?

You can repair the scratch using a touch-up paint stick or spray paint in the required RAL colour (RAL 9016 white is the standard colour). Paint stick and spray paint in RAL 9016 can be bought here on our website here: PAINT or you are welcome to contact our sales department via mail or phone.

What type of paint should I use to paint/re-paint the entire radiator?

Radiator paint is available as spray paint (in an aerosol can), as liquid paint or paint stick.

The standard colour of our radiators is RAL 9016 white.The procedure for re-painting powder-coated or wet-painted radiators is  as follows:

1. Clean the radiator.
2. If the radiator was originally powder coated, use PE powder paint.
3. If the radiator was originally wet painted, use synthetic, non-yellowing paint.
4. The paint should be water-based or a similar acrylic paint.
5. Allow sufficient curing time in accordance with the instructions for the paint concerned.


Hudevad radiators are as standard powder coated. Only in very rare cases do we use wet paint. 

What type of paint should I use to touch up paint damage to a radiator?

The paintwork of powder-coated or wet-painted radiators can be repaired with water-based acrylic paint.

Paint stick and spray paint in RAL 9016 can be bought here on our website here: PAINT or you are welcome to contact our sales department via mail or phone.

Which tapping possibilities are there?

A wide variety of tappings (aka connections) configurations are available. Please see the individual Product pages for details.

The standard tapping connections for Hudevad radiators are ½” female. Please note that our Horizontal radiators with center tappings have downward facing 3/4” eurocone (male) connections.

How can I take into account different temperature sets?

Hudevad has created up conversion tables, allowing the required radiator output to be calculated from any specific temperature set. The tables are available under each individual product or in the DOWNLOADS section on this website.

Are radiators available with other than ½” tappings?

Yes. Nipple sleeve adapters are available for 3/4” piping and can be found under FITTINGS

Are spare parts available for built-in and visible valve systems?

Both complete valves and spare parts are kept in stock and can be ordered directly in the Hudevad shop under ACCESSORIES or from your local heating engineers or wholesaler.


If you have any questions regarding spare parts and accessories please contact us per E-mail or phone.

What happens if I partly or completely cover my radiator ?

The location of a radiator can affect the heat output. In some cases, you may want to place a radiator under a radiator cover, under a wide window sill, hide the radiator behind a wooden front etc. - factors that, all in all, can have an effect on the radiator's heat output. Here you will find our REDUCTION FACTORS in the most common locations of our radiators and the reduction in heat output that this entails.

Note: The construction of the radiator cover must provide the necessary access for cleaning and maintenance of the radiator. The values given should only be used for estimates. Critical cases must be based on laboratory measurements.

Can I use a Hudevad radiator with reversed water flow?

We sometimes experience older systems where the flow and return has been reversed or cases where the radiators have been installed incorrectly and the flow and return pipes has been reversed. When new radiators need to be installed using the old pipes, the reversed pipes must therefore be taken into consideration.

You can use a Hudevad radiator for reversed water flow. We recommend you use one of our radiators with preset valves. (Tapping code 11 or 12) In addition you just need to use the following FITTINGS to "turn the flow":

1 pcs. Invertion fitting

2 pcs. Transition nipple in brass


The invertion fitting is mounted at the bottom of the radiator, where it makes sure to "cross" the water, from the flow to the return and vice versa.