Do heated towel rails need thermostatic valves?

Do heated towel rails need thermostatic valves?
A white ladder-style heated towel rail installed in a bathroomA white ladder-style heated towel rail installed in a bathroom

Thermostatic radiator valves are an excellent way of managing your central heating system and ensuring that radiators come on exactly when needed. TRVs are often recommended as a way to keep your heating costs economical.

However, should they be fitted on heated towel rails? In this article, we'll look at why this is not necessarily the best option.

The purpose of TRVs

Thermostatic radiator valves exist to help you have more control over your heating system.

On most TRVs, you will see a dial with a set of numbers which correlate to temperature ranges - 1 being lower, 5 being higher.

However, these numbers on the radiator relate to the temperature in the room, not to the temperature in the radiator - a common mistake many people make.

If a room is cold, the valve will detect this low temperature and allow more hot water into the radiator. Once the temperature in the room reaches the desired temperature, the valve will automatically close and stop any more hot water entering the radiator. As the temperature starts to drop, the valve will open again to help the room remain a constant temperature.

Set to 1, the temperature in the room will be fairly low when the valve closes. Set to 5, the temperature will need to get very high before the valve closes. Most people should set the dial to between 2 or 3.

This constant opening and closing of the valve means that hot water isn't jumped continually pumped into your radiators, helping to keep a consistent temperature and helping to reduce unnecessary energy wastage.

In the video below, a professional plumber gives an easy-to-understand breakdown of exactly how thermostatic radiator valves work.

Why TRVs are not always recommended on towel rails

In theory, it's completely possible to install a thermostatic radiator valve on a heated towel rail and in theory the process would be the same exactly as described above.

However, it's always recommended to have at least one radiator in your home to have manual valves, without a TRV. It's common practise for this radiator (or towel rail) to be in the bathroom.

The reason one radiator in your home needs to be TRV-free is as a safety mechanism. If for whatever reason, the other TRVs in your home failed to open or the boiler reached the desired temperature and activated the heat pump, water would still be able to pump through that radiator without causing damage to the boiler or pump.

As the majority of people buy heated towel rails with the intention of putting them in their bathrooms, it makes sense not to install a thermostatic radiator valve on them, especially as bathrooms tend to increase in temperature anyway due to the hot water.

If you already have a rad or rail in your bathroom with manual valves and you were planning on installing a heated towel rail in the kitchen or utility room, then adding a thermostatic valve would be a perfectly possible.

9 September 2020