Installing a radiator: What type do you need and where should it go?

Contemporary lifestyle image with grey designer radiator against light coloured wall
(Image credit: Getty Images)

If you are looking at installing a radiator, it might be because your old system isn't efficient enough anymore or simply because it's time for an upgrade. Either way, there will come a time when your old radiators will have to go. But how do you go about deciding on what replaces them?

If you are considering what type of radiator will work well in your home, you need to weigh up whether to splash out on designer radiators or settle for something more functional and, therefore cheaper. You will also need to look at what size radiator you need to make sure it will pump out enough heat for the space.

In this guide, we answer all the questions you might have when installing a radiator to help you make the right decision. 

Making the right choice when installing a radiator

Size, shape, style, colour and design are key aesthetics when choosing what type of radiator you want. But, you can’t forget the practicalities such as heat output as well as budget. 

If replacing your radiators like for like then then you won't have too many decisions to make. If your home currently has the popular white flat panel radiators and you want them replaced you already know what type of radiator, colour and size you’re looking for. But, you may want a different size radiator or perhaps to replace a single panel radiator with a double panel for more warmth.

Meanwhile, if you are looking for a completely new radiator design to install in your home, you will first need to determine what size radiator you need. Typically you will replace your old radiators with a similar size. This is because all the pipe work is already in place, and to change size will mean potentially expensive alterations to your piping system. 

When you’ve decided what size radiator you need you can start getting creative and think about the shape, style and colour. There’s plenty of styles and colours to choose – apart from white – with contemporary finishes like black, and anthracite being popular. It's worth noting that you can also paint a radiator to match any colour scheme you have.

Traditional column radiators like this Acova Volcanic 2 Column Radiator from B&Q give older homes a more cohesive look and feel. When it comes to shape it's often vertical as the opposite to horizontal, but if you want to get more left field you could splash out on something like this Reina Dimaro Designer Vertical Radiator from AQVA Bathrooms.  

Calculating BTUs

When installing a new radiator it is common to replace with a similar size radiator. But you need to check if the new radiator is going to give you enough heat. The BTU of a radiator helps determine if it will have enough output for a room. So what are BTUs? BTU stands for British Thermal Unit and is a measurement that works how much energy is needed to heat water. 

It effectively tells you the heat output of a radiator. Typically the higher the BTU the quicker a radiator will heat a room. But it's not that straightforward, you need a BTU rating that suits the room it's going in. To quickly work out the needed BTU in a room use B&Qs online Radiator BTU calculator. Once you get a BTU rating check the specs of the radiator you want to purchase to make sure it matches your needs. 

Choosing a radiator's position

Existing pipework typically determines where a radiator might be positioned and is an easy way to install a radiator. However, this position might not be ideal. If this is the case, repositioning the radiator might be necessary. Older properties often see radiators under windows, to help counteract cold air coming in. In a well insulated house with double glazing this is no longer necessary, but it's a good choice where single glazed windows exist. Plus, it's often an area where no furniture is placed, leaving it open for radiators.   

Installing radiators in the coldest part of a room is another option, often near a door, which when opened will help push the warm air around the room. But again, in well insulated homes this is not as effective.

Beyond these choices, an open wall where no furniture is going to be placed and won’t cause an obstruction is ideal. If you have a lack of wall space in a room, a vertical radiator may solve the problem. 


How much does it cost to install a radiator? 

The cost to install a radiator can vary greatly depending on the cost of the radiator(s), how many are being installed, whether you are doing it yourself and if any additional pipework, valves and TRVs are needed.

A basic white 600mm x 400m single panel radiator like the Flomasta White Single Panel Radiator from B&Q costs around £30. But a larger 1000mm x 600mm double panel version of the same radiator will cost around £75. The popular traditional radiator like this Honeywel 600 X 1145 mm Horizontal Triple Column White Traditional Radiator – again from B&Q will set you back nearly £400. 

Pipework prices will vary depending on whether you are using plastic or copper pipe, with copper pipe being around three times the price. Standard valves are relatively cheap with a TRV (Thermostatic Radiator Valve) like this GoodHome Thermostatic radiator valve head from B&Q costing around £10. Check out our How a TRV works guide to find out what they do and why you need them. 

A competent DIYer with previous experience should have no problem installing one or two radiators, but if you are not confident in tackling the job yourself you can expect to pay around £200 to fit a new double panel radiator. If you need more radiators fitting expect to pay £250-£500 for a day’s work. This will typically be three radiators plus draining and refilling the system.

Can I change a radiator without draining the system? 

If you are only changing a single radiator then you typically don’t need to drain down the system. Radiators typically have a lockshield valve and a TRV on each side of the radiator. To isolate the radiators switch off both valves, before undoing the nuts on the side of the radiator. 

You will need containers and towels when draining the water out of the radiator before placing it out of the way. Get your new radiator and fix into place, reattach the lockshield valve and a TRV and open both to fill the radiator. Finally, you need to bleed a radiator to get rid of any trapped air and repressurise the heating system.

Ideally you don’t want to drain down the system unless necessary as it will contain rust inhibitors and cleaner that help keep the system running efficiently. These will need to be replaced at extra cost. But, if replacing more than two radiators you will need to drain down the system 

If you are changing the heating system in your home as well as giving your radiators a refresh, be sure to check out all our content on types of boiler, oil boiler alternatives as well as gas boiler alternatives.

Steve Jenkins

Steve is Homebuilding & Renovating's DIY content editor, and has been a writer and editor for two decades. He is an avid DIYer with over 20 years of experience in transforming and renovating homes. He specialises in painting and decorating, but has strong all-round building skills, having previously worked in the industry for 10 years.