Thermostatic Radiator
Valve Installation

Not necessarily. In many cases we can use an isolation technique — a freeze kit or local valve isolation — to replace individual valves without draining the whole system. We'll confirm the approach for your specific system before starting and will only drain if there's no safe alternative.

Yes — they do different jobs. A whole-house smart thermostat (Nest, Hive, or similar) controls when the boiler fires. TRVs control the temperature in each individual room once the boiler is running. Together, they provide the most efficient and comfortable control possible. Without TRVs, every room heats to the same temperature regardless of whether it's occupied.

Smart TRVs (Tado, Drayton Wiser, Honeywell Evohome) connect to your home Wi-Fi and can be controlled via an app, set to schedules, detect when a window is open, and some integrate with weather data to anticipate heat demand. For most homes, standard TRVs are sufficient and cost-effective. Smart TRVs are most valuable in larger homes with many distinct rooms, or if you want granular remote control. We can advise on whether the extra cost is justified for your situation.

The room containing your main room thermostat — typically the hallway or living room — should not have a TRV. If a TRV were fitted there, it could close when that room reaches temperature, removing the signal that tells the boiler to switch off the rest of the system. That radiator should have a fully open lockshield valve or a manual valve instead. We always identify this radiator and fit accordingly.

Standard TRVs are sometimes DIY-fitted, but incorrect installation is common — cross-threading compression fittings, incorrect orientation of the valve head, or failure to re-balance the system afterwards. A poorly balanced system after TRV installation can cause some radiators to overheat while others stay cold. Given the relatively low cost of professional fitting and balancing, we recommend having the work done by a qualified engineer.

Balancing means adjusting the lockshield valve on each radiator so that hot water flows at the right rate through each one. In an unbalanced system, the radiators closest to the boiler receive too much flow and overheat, while radiators further away stay cool. When TRVs are fitted, the flow dynamics change — if the system isn't re-balanced, some rooms will be uncomfortable and the boiler will cycle inefficiently. We always balance after fitting.

A seized TRV pin is one of the most common heating faults. The pin inside the valve body gets stuck in the closed position — usually after summer when the heating hasn't been used. Sometimes you can free it by removing the TRV head and manually pushing the pin in and out. If it doesn't free, or if the valve body itself is corroded or weeping, replacement is straightforward and inexpensive.

Yes — under Part L of the Building Regulations, TRVs are required on all radiators when a new central heating system is installed or when a boiler is replaced, with the exception of the radiator in the room with the main thermostat. If your installer did not fit TRVs when replacing your boiler, the installation may not be fully compliant. We can retrofit TRVs to bring your system up to standard.

The Energy Saving Trust recommends: living rooms 21°C, bedrooms 18°C, bathrooms 22°C, hallways and landings 18°C, and unoccupied rooms 15°C (frost protection only). TRV heads are usually numbered 1–5 rather than showing degrees — a setting of 3 is approximately 20°C. We set each valve to a sensible starting point after installation and leave guidance on adjusting further.

A typical whole-house TRV installation — replacing manual valves on 8–12 radiators, balancing the system, and setting temperatures — takes a single working day. Single valve replacements take 1–2 hours. Smart TRV systems with a wireless hub and app configuration take slightly longer, typically 4–6 hours for a standard-sized house.

TRV heads (the temperature-sensing top section) typically last 10–15 years before the wax or liquid element loses accuracy. Valve bodies are more durable but can corrode or develop leaks over time. If your TRVs are more than 15 years old, are stiff to turn, or your rooms are consistently under- or over-heating even with the correct setting, replacement is worth considering.

We can, but we will always recommend fitting a magnetic filter at the same time if you do not already have one. Old sludge disturbed during valve replacement can circulate and damage the new valves. A Magnaclean or equivalent filter captures this debris and protects the whole system. We carry filters on the van and can fit one while we work.

These terms refer to the orientation of the valve body relative to the radiator and the pipe. A straight valve runs in line with the pipe, an angled valve turns 90°, and a corner valve turns 90° in a different plane. The right type depends on how your pipes enter the radiator — we bring a range on every job so we always have the correct fitting.