Frequently asked questions

The size of your traditional cast iron radiator depends on the size of the room it is intended to heat, how well insulated the space is and what the room is used for. Living rooms and bathrooms should be warmer than hallways and kitchens for example. The easiest way to calculate your heat requirement is to use Castrads’ heat requirement calculator.

Heat output is measured in Watts or British Thermal Units (BTUs). To calculate the approximate heat requirement of a room, take the volume (width ´ length ´ height) in metres and multiply this figure by 50 for lounges and dining rooms. For downstairs bedrooms, halls and kitchens multiply by 40. For upstairs lounges and dining rooms multiply by 40. For upstairs bedrooms, multiply by 35. For upstairs kitchens, multiply by 30. For downstairs bathrooms multiply by 90, for upstairs bathrooms multiply by 75. For rooms facing North add 15%. For French windows add 20%. For double glazing deduct 10%. For a very cold climate such as windy high altitude locations, add 10%. This gives you an approximate guideline in Watts. To convert this into BTUs, simply multiply the number of Watts required by 3.41.

Once one starts to look into more depth at the mathematics, the calculations can become fairly complicated. Castrads’ heat calculator simplifies the maths. Alternatively contact us and we will gladly do the legwork for you.

The heat requirement of a room is dependent on the measure of heat loss through surfaces such as windows, doors and walls. Each different material has its own unique U-value. U-value calculations can get rather complex – it is the measure of heat loss through one square metre of material for every degree difference in temperature either side of the interface. It is therefore indicated in units of Watts per square metre per degree Kelvin.

Our heat calculator is configured with average U-values for a range of common building materials.

The length of a radiator is given by multiplying the number of sections by the length per section in millimeters. The lengths of each section are given on Castrads’ technical data page. It is important to note that the length of a cast iron radiator is not the same as the distance from pipe centre to pipe centre. To account for valves and bushes each end of the radiator, add 120mm onto the length of the radiator, 60mm each end.

Castrads' cast iron radiators are built to order. Our customers supply us with a specification which we meet by assembling the radiators to the required size. The cast iron radiators are then pressure tested and painted to the desired colour, and finally baked at 100 degrees C to harden the paint surface. If the finish is powder coat, the radiators must be sent away to our powder coat specialist partners. This process can take up to 16 days.

When the radiators are ready to be dispatched they will be carefully packaged on pallet and delivered direct to the customer's house.

If the distance that you have is between two pipes, you must first of all subtract 120mm from that length to allow for the valves and end bushes. This will give you the length of the radiator. Take that length and divide it by the length per section of your chosen cast iron radiator model, given on Castrads’ technical data page. Round that to the nearest whole number to find the number of sections you require. You should then multiply the number of sections by the section length and add on the 120mm, just to be sure that you have not exceeded the distance between the pipes.

You can have any length of cast iron radiator you require (within reason). Castrads does not sell oversize radiators online to avoid the complications that arise with delivery. Extra large cast iron radiators must be delivered partially disassembled to be reassembled on site. To do this you will need to hire an assembly tool from us. The assembly tools are engineered specifically for Castrads and are not available commercially. The tool costs £80, with a £50 deposit refundable upon return of the tool to Castrads. Castrads provides free telephone support to customers assembling at home as well as an in depth advice sheet tackling all the common issues.

Traditional cast iron radiators are extremely heavy. Getting them up stairs can be a nightmare, so for this reason Castrads sets a weight limit of 140kg on radiators that are to be transported up flights of stairs and 170kg on radiators that are to be installed on the ground floor. Of course Castrads can and do supply radiators that are larger than this, but The Company accepts no liability for damage sustained during manoeuvers.

Yes. Cast iron radiators work on exactly the same principle as modern radiators. Cast iron radiators usually have a larger internal volume, so they take a few more minutes to warm up. This also means that they stay warm well after the boiler has been turned off.

The maximum working pressure for Castrads cast iron radiators is 90 pounds per square inch (psi). Most systems never exceed 45 psi. Very tall buildings, eg 10 storeys may have 90psi at the lowest level.

We strive to complete all orders within 7 days from the point of purchase. Once your radiators have been hand assembled, tested and finished to your specifications, we will contact you by telephone to arrange a day for delivery that is convenient for you.

Spray painted finishes are carried out at Castrads' HQ in Cheshire. Our expert finishing technicians use industry leading spray booths to paint each radiator to the customer's requirements. Sprayed finishes allow the naturally pitted surface of cast iron to show through.

Cast iron radiators finshed in spray paint will be ready for dispatch 7 days from the date an order is confirmed (so long as the paint is in stock).

Powder coat is applied as a free-flowing, dry powder. The coating is applied to an electrostatically charged cast iron radiator and is then cured under heat to allow it to form a tough outer shell.

Powder coating gives a smooth finish, so the rough cast iron is completely covered by a thick plastic skin. Castrads has a well established partnership with a local powder coating specialist. Powder coated finshes may take up to 16 days from confirmation of an order to date of dispatch.

See cast iron radiator finishes for more information

A resounding no! Castrads is the only company selling cast iron radiators in the UK to offer free paint (to the best of our knowledge). Pewter is a Cromadex paint with 30% gloss. It is free because we sell a lot of it.

Pewter is a neutral colour that suits all interiors. Unlike white or black, which can both dominate a room and reduce the contrast between low and highlights, pewter emphasises the patina of the radiator while remaining fairly understated.

It is the colour of the cast iron radiators in the company founder's house.

A thermostatic radiator valve measures the room temperature and adjusts the flow accordingly. It does this by means of a sensor in the centre of the handle. As the room temperature rises expansion causes a rod to push down on the valve mechanism restricting the inlet flow of hot water.

The desired temperature is set by turning the handle. At the outlet (return) end of the radiator is attached the lockshield valve. This is adjusted by the plumber to balance flow rates through the system, ensuring all radiators get an adequate share of the available hot water.

Thermostatic radiator valves are recommended by plumbers and the government as energy saving. They are, if the temperature is set and maintained. In practice people may think it's a little chilly then turn the valve full on. Left fully open they will save no energy at all.

The term thermoregulating valve is also used to mean thermostatic radiator valve. Strictly speaking a thermoregulating valve has both hot and cold supplies, such as on a shower, but more and more the term has come to have both meanings.

Manual radiator valves have no thermostatic control. The maximum flow of hot water out of the radiator is controlled by adjusting the lockshield valve on the radiator outlet as for thermostatic valves. The inlet valve with manual handle is used to turn the radiator on and off.

Castrads radiator valves are all bidirectional, however at abnormally high flow rates (we've come across this on one occasion only) a rattling can occur if the control valve is on the outlet (return). For best results, hot water should flow in through the control valve and out of the lockshield.

1. Screw the valve tail into the bottom of the radiator, using a sealant such as PTFE tape or LSX sealant, available to buy here. Be sure not to overtighten the valve tail as this can crack the bushes.

2. Slide the valve body over your copper pipe, ensuring the olive (little brass ring) is inside the valve. When the bottom nut is tightened, the olive is compressed, forming a watertight seal around the copper pipe.

3. Connect the valve body to the valve tails by tightening the large nut located on the end of the tail onto the threaded end of the valve body.

The weight of the radiator rests on the floor in a normal installation. However it is possible to rock the radiator or even pull it over if no wall stays are fitted. For this reason Castrads recommends 1 wall stay for radiators up to 11 sections long and 2 for every extra 11 sections.

Some radiators, such as the Short Kings (470mm and 570mm), the Queen 510mm, our 9 column radiators and our 5 column radiators (if rested on a steady base such as wooden blocks) are almost as wide as they are tall, so are stable and won’t fall over. For this reason these models do not require the security of a wall stay.

It is possible to mount the radiators off the floor using Castrads' wall brackets. Two wall brackets and two wall staysare required for this purpose for up to 14 sections of radiator.

Castrads accepts most major debit and credit cards, although at this time we are unable to accept American Express. Castrads does not add a surcharge for credit card sales.

We use Google Checkout for online sales. Google Checkout accepts Mastercard, Visa, Visa Electron and Solo.

We accept cheques with a valid cheque guarantee card made payable to Castrads. Electronic bank transfers are also possible. Please contact us for more information.

All prices are quoted exclusive of VAT. At present, VAT is 17.5% in the UK.

Radiator delivery in UK

Delivery of radiators is by The Pallet Network, a nationwide company with depots across the UK. Castrads charges £50 exc. VAT for radiator delivery to most places in mainland UK. Please ring us on 0161 297 0015 or email us for a firm quote on carriage.

There are 2 collections per week on Tuesdays and Thursdays for delivery Monday – Friday, 9am – 5pm. The lorry travels overnight to a hub and a local haulier delivers to you. The lorry comes with a tail lift, so the driver can unload the pallet by himself. He has a pallet truck, so he can wheel the pallet as close as possible to the front door, as long as there’s no obstacles in the way such as a gravel drive or steps up from the footpath.

The pallet comes wrapped in black plastic and inside is a grey plastic bag with wall stays, valves, touch up paint etc. Please be sure to check that the grey plastic bag is there and has not been tampered with before you sign for the goods. When you have someone to help take them in the house, remember not to carry them in as they are on the pallet, but to lift into an upright position as per instructions posted with the invoice. 


Delivery to Ireland

Delivery of radiators to EIRE costs £90 exc. VAT. Delivery to Northern Ireland is £80 exc. VAT.

Delivery outside of UK & Ireland

Castrads is increasingly shipping cast iron radiators to mainland Europe, North America and Australasia. Please contact us for a shipping quote.

If you are ordering valves and accessories, delivery will be by UK Mail or Royal Mail dependent on the size of your consignment. If your consignment is sent via UK Mail, Castrads will be able to give you a number which you can use to track your goods at the UK Mail website.

Towel rails are always sent via UK Mail’s next working day parcel service.

All of Castrads' cast iron radiators are guaranteed for a period of 10 years, and Castrads' valves for a period of 5 years. The guarantee not only covers manufacturing defects but also damage during transit. Castrads prides itself on good customer service and in the very unlikely event of faulty goods, Castrads will replace or refund those offending articles with like for like.

If for whatever reason you decide you don't like your cast iron radiators, you can return them to Castrads for a full refund within 30 days from the date of purchase, minus the cost of transportation and a 30% handling fee. The goods must of course be in the same state they left the factory and free of any damage.

Please see our Terms and Conditions for more details.