Upgrading your heating controls is one of the most cost-effective changes you can make to your heating system. A modern programmable thermostat or smart heating controller can reduce annual heating bills by up to 30% — not by providing more heat, but by ensuring the system only runs when it needs to.
Unlike gas components, heating controls operate at low voltage and are legal for homeowners to install themselves. If you’re confident working with wiring, a thermostat or programmer upgrade is a realistic DIY job.
Product Types
Room Thermostats
A room thermostat measures the air temperature in a reference room (usually the living room or hall) and switches the heating on or off to maintain the set temperature. Most existing systems use a basic two-position stat — either calling for heat or not.
Wired vs wireless: Wired room thermostats connect directly to the boiler via the existing cable from the boiler or programmer. Wireless stats use a battery-powered transmitter paired to a receiver wired at the boiler — easier to install, no cable runs required.
Brands we stock: Honeywell Home, Drayton, Salus, Sunvic, Siemens
Common replacements:
- Honeywell T6360 — standard wired stat, replaces most older Honeywells
- Drayton RTS8 — wired replacement for Drayton and compatible systems
- Salus RT500RF — wireless battery-powered stat with digital display
Smart Heating Controls
Smart thermostats learn your schedule, allow remote control via smartphone app, and can integrate with weather data to anticipate heating demand. The genuine energy savings are well documented — Nest claims 23% average, Hive claims up to 30%.
Systems we stock:
Hive Active Heating: British Gas’s smart thermostat system. Requires a Hive Hub (included in starter kits). Compatible with most UK combi and system boilers with OpenTherm or standard on/off control. DIY installation is supported — Hive’s app walks through the wiring process step by step.
Google Nest Thermostat: Learning thermostat that builds a schedule from your adjustments over the first week of use. Works via OpenTherm where supported (better temperature precision) or standard switching.
Honeywell Home T6: Mid-range smart stat from Honeywell. Simpler than Nest or Hive, but reliable and widely compatible. Good choice for rental properties where a complex smart system is unnecessary.
Drayton Wiser: Modular smart system allowing per-radiator temperature control combined with a central hub. Particularly effective for larger properties with rooms used at different times.
Programmers and Timers
A programmer (or timeswitch) controls when the heating and hot water switch on and off, independent of the thermostat which controls temperature. Most systems have both — a programmer sets the schedule, the thermostat determines whether that schedule actually calls for heat.
7-day programmers allow different schedules for each day of the week — essential for anyone with a variable schedule. We stock 7-day replacements from Honeywell, Drayton, and Danfoss.
2-channel programmers control heating and hot water independently. Important for homes with a hot water cylinder (system boilers and traditional heat-only boilers) where hot water and heating timing may differ.
Cylinder Thermostats
A cylinder thermostat clips onto a hot water storage cylinder and controls the immersion heater or the heating zone valve feeding the cylinder. When water in the cylinder reaches the set temperature, the stat cuts the heat source.
Cylinder stats fail over time and may result in the cylinder overheating (not reaching setpoint), not heating at all, or erratic hot water supply.
Legal note: Cylinder thermostats are DIY-replaceable. They connect to the zone valve or immersion heater at low voltage.
Frost Stats
Frost protection thermostats prevent heating system components from freezing when a property is vacant. They typically override the programmer to fire the boiler if temperature drops below 5–7°C. Standard fitment for holiday properties and investment properties.
Zone Valves
Motorised zone valves direct hot water to either the heating circuit or the hot water cylinder on call from the programmer and cylinder stat. A failed zone valve presents as either constant heating with no hot water, or constant hot water with no heating.
Zone valve replacement is a plumber’s job given the water connections involved, but the actuator head can often be replaced without isolating the system — reducing labour time significantly.
Upgrading Your Controls: What’s Possible
Combi Boiler Systems: Combi boilers are the simplest to control — they supply hot water on demand and heat the home via a single heating circuit. You need: a thermostat (wired or wireless) and optionally a programmer. A smart thermostat covers both in one device.
System Boilers with Hot Water Cylinder: More complex. You need: a 2-channel programmer (separate heating and hot water times), a cylinder thermostat, a room thermostat, and typically motorised zone valves. Smart systems like Drayton Wiser can replace the entire control chain.
Heat-Only (Regular) Boilers: Traditional boiler and cylinder systems with a separate header tank. Same control requirements as system boilers — 2-channel programmer, cylinder stat, room stat, zone valves.
DIY Installation Guidance
What’s safe to DIY: Room thermostats, programmers, smart thermostats (most configurations), cylinder stats, frost stats. These operate at low voltage and do not involve gas connections.
What requires a Gas Safe engineer or electrician: Any wiring inside the boiler casing, rewiring that runs new mains cables, connecting a new heating zone to the boiler controls.
If you’re unsure whether your planned upgrade is DIY-safe, call our helpline at 0330 124 5678 — we’ll talk through your existing setup and the target configuration.