Underfloor Heating vs Radiators: Which is the Winner?

What is a Radiator?

Radiators have long been the heat exchanger of choice for most households in the UK. They are connected to the central heating system and usually made from a heat-conducting metal like aluminium or cast-iron. The typical radiator is made up of two panels, connected by a grill, with fins running between them in a zig-zag pattern. The heat output is controlled by thermostatic radiator valves.

When your boiler runs heated water to the radiator system, the heat output happens through convection. This means that the radiator heats the air directly above it and, as the heat rises, cold air falls, which is then heated itself, creating an airflow loop that circulates hot air throughout the room. Radiators are effective at giving a blast of heat to the room, and there are countless design options available.

What is Underfloor Heating? 

Underfloor heating uses a network of pipes or cables to heat the floor of a room. There are two main types of underfloor heating systems: 

• Hot water-based underfloor heating

Hot water underfloor heating, sometimes called hydronic or wet underfloor heating, works on the same principle as the traditional central heating system. There are pipe networks beneath the floor, and when the system is switched on, hot water flows through them, radiating heat to the floor space above it.

• Electrical underfloor heating

The ‘dry’ system of underfloor heating gets its power from the electric grid, the same source of electricity for the mains supply in your home. Electrical wiring sits in the cavity underneath the floor and provides radiant heat when it is turned on. This wiring can be loose, or inlaid in a purpose-built mat. 

Design and Installation

Getting the correct ‘look’ for a room is an important consideration when designing a space, and that’s one of the main reasons so many people are turning to underfloor heating. It allows you to keep the room’s heating system totally invisible, which allows spaces to have a more ‘open’ feel, without wall space needing to be broken up by radiators. On the other hand, when it comes to design choice for radiators, your options are practically unlimited. Alongside traditional models, there are countless customisations you can select in terms of colour, shape and size, and many people use feature radiators for a conversation piece in a room.

In terms of installation, most homes in the UK are already installed with radiators, meaning you don’t have to do anything – or at least, very little. Treated well and properly maintained, a typical radiator is good to go for at least ten, if not fifteen, years. When it does finally need replacing, it’s simply a matter of removing the old one, fixing a new one to the wall, and connecting it to the central heating system. This is a quick and easy job for a professional. 

If you’re looking to install underfloor heating in a new build, the process is also relatively painless, since you’re able to put the system in place before you add the final flooring level. Installing underfloor heating as a retrofit, though, can be more of a challenge. You can save some hassle if you go for electric underfloor heating, because the wiring tends to be quite thin and can be squeezed into place. Hot water underfloor heating requires more space for the pipes, and this may involve elevating the floor level, a particular pain point in older homes. You’ll also need to think about the structural integrity of the flooring, and whether it will conduct heat properly, too.

Day-to-Day Running

The daily, operational efficiency of the two systems is another crucial factor. While the typical central heating system runs at 70°C-90°C, water-based underfloor heating works at only about 35°C. This means the water needs much less heating, and that can lead to big savings on your energy bills. Underfloor heating is especially efficient when used in conjunction with a heat pump stationed outside the home.

Generally speaking, underfloor heating tends to be more efficient for large, open-plan spaces, whereas radiators are more effective at getting a smaller room (like a bedroom or bathroom) up to a comfortable temperature. With that said, radiators are much faster-acting than underfloor heating, so you may find that underfloor heating systems need to be turned on for longer. And, while radiators have some tried-and-tested metals as their core material, effective underfloor heating may need to be paired with particular flooring, like vinyl or specially-engineered wood.

As we said earlier, a good radiator can continue running at peak efficiency for fifteen years or more. However, to see that kind of lifespan you would need a top-line radiator unit and to take good, regular care of it. On the other hand, underfloor heating manufacturers boast that their water-based piping can run happily for more than fifty years, though again, this would entail semi-regular maintenance, checks and servicing. It’s important to remember that where radiators are comparatively easy to maintain, underfloor heating can be far more difficult to uncover for repairs or replacement.

What About the Running Cost?

When it comes to the running cost of underfloor heating and a radiator system, the figures are broadly similar. Running costs depend more on how much you choose to spend on energy and your home’s insulation-efficiency than the systems themselves. However, when you combine underfloor heating with a heat pump it becomes highly efficient, and that leads to big savings on cost. The price of electricity is much higher than the price of gas, and as a result the running cost of electrical underfloor heating can get significantly higher.

Things to Think About

• Insulation efficiency 

Any decision about heating systems needs to consider the quality of the existing insulation and windows in your home. It may be a good idea to get an estimate of your room’s heat loss, and base your decision on that – often, it’s worth upgrading your insulation at the same time as your heating system, as that can have a massive impact on your heating bills.

• Hybrid systems

Many people choose underfloor heating in their bigger, most-used rooms like the living room or kitchen (especially if they’re open plan), and have radiators in the bedroom or bathroom. This can be extremely energy efficient and makes good sense economically because you can adjust your heating usage to suit your lifestyle.

• Allergies and dust mites

One drawback of radiators is that the process of convection stirs up dust in the room and allows it to spread, which can be troublesome for people with allergies. An underfloor heating system does away with this concern.

• Space for underfloor heating controls

If you do decide to go for water-based underfloor heating, be sure to earmark a space somewhere in the house to keep your control manifold. This is essentially the nerve centre of your system and allows you to independently control different areas of the house, though it’ll need its own dedicated space. 

Should You Choose Underfloor Heating or Radiators? 

A better question might be: between underfloor heating and radiators, which system is best-suited for my home? With modern building design, underfloor heating may be a good match for open plan, well-insulated spaces, especially if it’s installed as part of the construction process. On the other hand, radiators are better for more traditionally-designed houses; they give you a quicker blast of heat, and are generally easier to maintain.