Smart Thermostats and Heating Controls | Portsmouth Electrician’s Guide
Your heating system might have a perfectly good boiler, well-maintained radiators, and pipework that’s in decent condition — but if the controls telling it when and how to run are outdated, the system can’t work efficiently no matter how well the components perform. A basic timer and a single room thermostat mounted in the hallway was the standard approach for decades, and across Portsmouth there are thousands of homes still running their heating on exactly this setup. The boiler fires at the same time every day regardless of whether anyone’s home, heats every room to the same temperature whether it’s occupied or not, and the only way to adjust it is to walk to the hallway and turn a dial.
Smart thermostats and modern heating controls change this fundamentally. They learn your schedule, respond to whether you’re home, let you adjust the heating from your phone, and in some cases control individual rooms independently. The question most Portsmouth homeowners ask is whether the energy savings justify the cost. This guide explains what’s available, what each option costs to install, and whether the investment makes practical and financial sense for your home.
What Does a Smart Thermostat Do?
A smart thermostat replaces your existing room thermostat and programmer with a connected device that controls your heating through an app on your phone, learns your habits over time, and optimises when the boiler runs to maintain comfortable temperatures while minimising wasted energy.
At a basic level, every smart thermostat lets you set heating schedules from your phone rather than pressing buttons on a programmer mounted on the wall. You can adjust the temperature remotely — turning the heating on before you leave work so the house is warm when you arrive, or turning it off when you’ve forgotten and left for the weekend. Most detect when you’ve left the house using your phone’s location and can reduce or switch off the heating automatically rather than running to a schedule in an empty property.
Beyond basic control, different brands offer different levels of intelligence. Some learn how long your house takes to reach target temperature and adjust the firing time accordingly — starting earlier on cold mornings and later on mild days. Some integrate with weather forecasts and anticipate how the outside temperature will affect the heating demand. Some offer room-by-room control through individual radiator valves that communicate with the thermostat wirelessly.
The Main Brands Compared
Five brands dominate the UK smart thermostat market, each with a distinct approach and price point.
Nest — now owned by Google — was one of the first smart thermostats and remains one of the most recognisable. The Nest Learning Thermostat detects your patterns over the first week and builds a schedule automatically, adjusting as your habits change. It integrates with Google Home for voice control and shows your energy usage history. The Nest thermostat itself costs £180 to £220 plus installation. It replaces your existing thermostat and programmer with a single unit and controls the boiler on a whole-house basis — every radiator gets the same temperature unless you add separate smart radiator valves.
Hive — owned by British Gas — is the most widely installed smart thermostat in the UK. The Hive system includes a thermostat, a receiver that connects to the boiler, and a hub that links everything to your WiFi and the Hive app. It offers scheduling, geolocation, and remote control. Hive also sells smart radiator valves for room-by-room control at around £40 to £55 per valve. The thermostat and receiver cost £150 to £200 plus installation. The system is straightforward and reliable without the learning features of the Nest.
Tado takes a different approach by emphasising room-by-room control from the outset. The starter kit includes a smart thermostat and internet bridge, with wireless radiator valves available for individual room control. Tado uses geolocation aggressively — detecting when the last person leaves the house and reducing heating automatically, then pre-heating before the first person returns. The starter kit costs £130 to £180 plus installation, with additional radiator valves at £50 to £70 each. For a three bedroom Portsmouth house with eight radiators, a full Tado system with valves on every radiator costs between £500 and £750 before installation.
Drayton Wiser offers a mid-range system with room-by-room control at a more accessible price point than Tado. The kit includes a hub, thermostat, and one or two radiator valves, with additional valves available at £30 to £45 each. The starter kit costs £100 to £160 plus installation, making it one of the most affordable routes to full room-by-room control. Wiser integrates with Amazon Alexa and Google Assistant for voice control.
Honeywell Evohome is the most comprehensive multi-zone system available. It controls up to twelve separate heating zones, each with its own wireless radiator valve and independent temperature schedule. The system is popular with larger Portsmouth properties where different rooms have significantly different heating requirements — bedrooms needing warmth in the evening, living rooms during the day, home offices during working hours only. A full Evohome system for a four bedroom house typically costs £500 to £900 before installation. The complexity and granularity of control suits homeowners who want precise management of their heating rather than a simple on-off upgrade.
Installation Costs
The installation cost depends on your existing heating controls and how much electrical work is needed to connect the new system.
A straightforward thermostat replacement — removing your existing room thermostat and programmer and installing a smart thermostat with its receiver at the boiler — typically costs between £80 and £150 for the electrical work. If the existing wiring between the thermostat position and the boiler is compatible with the new system, the installation is quick — typically one to two hours. Most modern combi and system boilers across Portsmouth work with all major smart thermostat brands without wiring modifications.
Adding smart radiator valves for room-by-room control is a plumbing job rather than an electrical one — each valve replaces an existing thermostatic radiator valve on the radiator. The valves pair wirelessly with the thermostat hub, so no additional wiring is needed. Fitting each valve takes around fifteen minutes. For a house with eight to ten radiators, valve installation takes a couple of hours.
An installation requiring new wiring — where the existing thermostat cable is incompatible, damaged, or doesn’t reach the new thermostat position — takes longer and costs more. Running new cable from the boiler to the thermostat location typically adds £50 to £150 depending on the distance and the route the cable needs to take.
Total installed costs for the most common setups across Portsmouth:
A Nest or Hive thermostat with professional installation typically costs £250 to £400 all-in. A Tado or Wiser system with four to six room valves and installation typically costs £400 to £700. A full Honeywell Evohome system with eight to twelve zones and installation typically costs £700 to £1,200.
Do They Actually Save Money?
The energy savings from a smart thermostat are genuine but vary depending on how you currently use your heating and how efficiently you program the smart system.
The biggest savings come from eliminating wasted heating — the hours when the boiler runs to a timer schedule in an empty house because nobody changed the programmer. A smart thermostat with geolocation detects when the house is empty and reduces or stops the heating automatically. For a household where both adults work and the children are at school, this can eliminate four to six hours of unnecessary heating per day during the week.
Independent research typically estimates annual savings of £75 to £150 for a basic smart thermostat replacing a traditional programmer and thermostat. Adding room-by-room control with smart radiator valves increases the saving because rooms you’re not using — spare bedrooms, bathrooms during the day, the kitchen overnight — run at lower temperatures rather than the same temperature as the rooms you’re actually in. Full zoned control can push annual savings to £150 to £300 depending on the property size and how many rooms are genuinely controlled independently.
For a typical Portsmouth terraced house or semi spending £800 to £1,200 per year on gas, a smart thermostat saving ten to twenty percent represents £80 to £240 annually. A basic system costing £300 installed pays for itself within one to three years. A full zoned system costing £700 pays for itself within two to four years.
The savings are most significant for larger properties with rooms that aren’t used all day, properties where occupants are out regularly, and homes where the existing controls are basic timer-and-dial setups that haven’t been optimised. The savings are more modest for small properties where every room is used throughout the day and the existing controls are already programmed efficiently.
Boiler Plus Compliance
Since 2018, the Boiler Plus legislation requires all new combi boiler installations in England to include time and temperature control plus at least one additional energy-saving measure. A smart thermostat with automation and optimisation features satisfies this requirement — making it a practical compliance solution as well as a comfort and efficiency upgrade. If you’re having a new boiler installed in your Portsmouth property, your installer should discuss smart thermostat options as part of the installation rather than fitting a basic programmer that doesn’t meet the current requirements.
Is It Worth It?
For most Portsmouth homeowners, a smart thermostat is worth the investment — not primarily for the energy savings, though those are genuine, but for the daily convenience of controlling your heating from your phone, the comfort of coming home to a warm house without running the heating all day, and the waste elimination of heating rooms and hours that don’t need it.
The decision between a basic smart thermostat and a full room-by-room system depends on your property. A one or two bedroom flat doesn’t benefit significantly from zoned control because there aren’t enough rooms to create meaningful zones. A three or four bedroom house with rooms used at different times of day benefits considerably. A larger property with five or more rooms where occupancy varies throughout the day benefits most of all.
If you’re considering a smart thermostat or heating control upgrade at your Portsmouth property, get in touch. We’ll assess your existing controls, discuss which system suits your home and your heating habits, and provide a clear quote for the supply and installation.