The Best Smart Thermostats & Radiator Valves Under £100 in the UK

Upgrading to smart heating is one of the most effective ways to reduce your energy bills, but the initial cost of a premium system can be a significant barrier. The good news is that you don’t need to spend hundreds of pounds to get started. For under £100, you can begin to add intelligent, app-based control to your home heating, one room at a time.

This guide focuses on the most affordable entry points into smart heating. We’ll show you the best budget-friendly smart radiator valves and starter kits, explain what features you can expect at this price point, and help you make a smart investment that pays for itself in energy savings.

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What Can You Realistically Get for Under £100?

Entering the smart heating market with a budget of less than £100 requires a clear understanding of what you're buying. At this price, you are primarily looking at individual components or very basic starter kits, not comprehensive, whole-house systems. The key is to see it as a starting point for a more capable system you can build over time.

 

Smart Radiator Valves (TRVs): The Best Place to Start

The most impactful and affordable first step is to invest in smart Thermostatic Radiator Valves (TRVs). These devices replace the existing twist-valves on your radiators, allowing you to control the heating of individual rooms from your smartphone. This is the foundation of zonal heating—the principle of only heating the rooms you are using, which is a primary driver of energy savings. For a detailed explanation of how they work with a central thermostat, see our guide on Smart Thermostat vs Smart TRVs: Do You Need Both?.

 

Basic Starter Kits

For just under the £100 mark, you can find a few starter kits. These typically include one smart radiator valve and the internet hub required to connect it to your Wi-Fi. This is an excellent value option as it provides everything you need to control a single radiator intelligently, often with the option to add more TRVs later.

 

The Importance of a Hub (and its cost)

Most smart heating devices don't connect directly to your home's Wi-Fi router. Instead, they use a more energy-efficient wireless protocol to talk to a dedicated hub or bridge, which is then plugged into your router. When buying individual TRVs, it's crucial to remember that they will not work without a compatible hub from the same brand. If you don't already own one, you must factor the cost of the hub into your purchase, which is why a starter kit is often the best-value entry point.

 

The Best Smart TRVs & Starter Kits Under £100

Here are our top recommendations for affordable smart radiator valves and starter kits. We've selected these based on value for money, features, and ease of use for those just starting their smart heating journey.

 

TP-Link Kasa KE100 KIT Smart Radiator Valve Starter Kit

 

  • Best for: The absolute lowest entry cost into a complete, hub-included smart TRV system.
  • Key features: Includes one smart TRV and the required Kasa Smart Hub. Features remote app control, scheduling, and voice control via Alexa and Google Assistant.
  • Performance/Results: Provides reliable, app-based control over a single radiator, allowing you to create schedules and avoid heating an unused room. The Kasa app is straightforward and easy to use.
  • Drawbacks: This system can turn a radiator down or off on a schedule, but it cannot independently "call for heat" to turn the boiler on. The wider Kasa smart home ecosystem is less extensive than rivals like Hive.
  • Ongoing cost/maintenance: Requires two AA batteries, which will need replacing every 1-2 years. No subscription is required.
  • Price: Approx. £36

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Eve Thermo Smart Radiator Valve

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  • Best for: Apple users who are already invested in the HomeKit ecosystem and want a seamless, high-quality TRV.
  • Key features: Designed exclusively for Apple HomeKit. Communicates via Thread for a responsive and robust connection (with a compatible border router like a HomePod mini). Features open window detection and a clean, minimalist design.
  • Performance/Results: Offers excellent integration with Apple's Home app, allowing control via Siri and inclusion in HomeKit automations. It's quiet, responsive, and reliable within the Apple ecosystem.
  • Drawbacks: It is completely incompatible with Android, Amazon Alexa, or Google Assistant. It requires an Apple Home hub (like a HomePod or Apple TV) for remote, out-of-home control. It's also expensive for a single valve.
  • Ongoing cost/maintenance: Powered by two AA batteries. No subscription fees.
  • Price: Approx. £70

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Tado° Add-on Smart Radiator Thermostat

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  • Best for: Expanding an existing Tado° smart heating system, or for those planning to buy a full Tado° starter kit in the near future.
  • Key features: Compact and stylish design with a clear LED display. Integrates with the powerful Tado° app, which offers geofencing, weather adaptation, and detailed energy reports.
  • Performance/Results: When part of a full Tado° system, these TRVs are excellent. They can call for heat from the boiler, allowing for true room-by-room temperature control. The hardware is reliable and well-made.
  • Drawbacks: This is an add-on product and is non-functional without the Tado° Internet Bridge (which comes in a starter kit). To unlock the full automation features (like automatic geofencing), a monthly subscription of £3.99 is required. If you're new to smart heating, you should start with the Complete 2025 Buying Guide.
  • Ongoing cost/maintenance: Requires two AA batteries and the optional but recommended monthly subscription.
  • Price: Approx. £60

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Hive Smart Radiator Valve

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  • Best for: Households that already use Hive for their main thermostat and want to easily add zonal control to a few key rooms.
  • Key features: Seamless integration with the Hive app and wider ecosystem of products. Simple, intuitive 'twist-and-push' manual control. Backed by a major UK brand (Centrica/British Gas).
  • Performance/Results: Works effectively within the Hive ecosystem to provide room-level scheduling and control. The "Heat on Demand" feature allows the TRV to trigger your Hive thermostat to turn the boiler on.
  • Drawbacks: This is an add-on product and will not work without the Hive Hub (sold separately or as part of a thermostat starter kit). Its multi-zone control is functional but less advanced than dedicated systems. See our Complete 2025 Buying Guide for more details.
  • Ongoing cost/maintenance: Uses two AA batteries. No subscription is required for core functionality, but advanced cost tracking is part of the Hive Plus subscription.
  • Price: Approx. £54

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Budget Buying Guide: Key Checks Before You Buy

Making a smart purchase on a tight budget means paying close attention to the details. Before you click "buy" on an affordable smart TRV, run through this quick checklist to ensure it’s the right fit for your home and won’t lead to frustration later.

 

1. Check Your Radiator Valve Compatibility

Smart radiator valves are designed to replace the heads of existing thermostatic radiator valves (TRVs), not older, simpler manual valves. A TRV typically has numbers on it (e.g., 1-5) and can be twisted to set a temperature. A manual valve is usually just a simple on/off tap. While most smart TRVs come with adaptors for the most common fittings in the UK, it’s wise to check your current valves first. For a deeper dive, our Smart Thermostat Compatibility: A 5-Minute Check for Your Boiler (UK Guide) has more information.

 

2. Do You Already Have a Compatible Hub?

This is the most critical check. If you are buying an "add-on" valve like the Tado° or Hive TRV, you must already own the corresponding Internet Hub from that brand for it to work. If you are starting from scratch, a full starter kit like the TP-Link Kasa KE100 is your only viable option at this price point, as it includes the necessary hub in the box.

 

3. Consider the Upgrade Path

Think about your long-term goal. Do you just want to control one problematic radiator, or is this the first step towards a whole-house system? If you plan to expand, it’s often better to invest in a product from a major ecosystem like Hive or Tado°. This ensures that when you're ready to add more TRVs or a central smart thermostat, all the components will work together seamlessly in one app.

 

4. Factor in Ongoing Costs (Batteries & Potential Subscriptions)

The initial purchase price isn't the final cost. All smart TRVs run on batteries (typically AA), which will need replacing every one to two years. This is a minor but recurring expense. More significantly, be aware of business models like Tado°'s, which places its best automation features behind a £3.99 monthly subscription. While the TRV works without it, you'll need to pay to get the full "smart" experience.

 

What You Won't Get for Under £100

It's just as important to manage expectations and understand what this budget doesn't cover. For under £100, you are getting an entry point into smart heating, not a comprehensive, top-tier system.

Typically, you will not get:

  • A Complete Central Thermostat Kit: Full starter kits that replace your main wall thermostat (like the Hive Thermostat Mini or Tado° V3+) usually start at around £120-£150.
  • Multi-TRV Bundles: Kits that include a hub, a thermostat, and multiple radiator valves (like the excellent value Drayton Wiser Multi-room Kit) are generally priced over £200.
  • Premium Features: High-end hardware with glass and metal finishes, advanced learning algorithms, or large colour displays found on devices like the Google Nest Learning Thermostat are firmly in the premium category.

If your budget can stretch a little further, you can access a much wider range of complete systems. We recommend exploring our guides to the Best Smart Heating Systems Under £150 (UK) and the Best Smart Heating Systems Under £250 (UK) to see what a slightly larger investment can offer.

 

Frequently Asked Questions (FAQs)

 

Can you get a smart thermostat for under £100?

It is very rare to find a complete smart thermostat starter kit (which replaces your main wall thermostat and includes the internet hub) for under £100 from a major brand. At this price point, you are typically buying individual smart radiator valves (TRVs) or a very basic TRV starter kit.

 

Is it worth getting smart radiator valves?

Yes, absolutely. Smart TRVs are one of the most cost-effective energy-saving devices you can install. By allowing you to create schedules for individual rooms, they stop you from wasting money and energy heating parts of your house that are empty, which is a major source of high bills.

 

Can you just use smart TRVs without a smart thermostat?

You can, but their function is limited. A smart TRV on its own can turn a radiator down or off according to a schedule. However, it cannot turn the boiler on. For a TRV in a cold room to be able to trigger the heating for the whole house, it needs to be part of an integrated system with a compatible smart thermostat.

 

What is the cheapest way to get smart heating?

The cheapest way to start is with a TRV-only starter kit, like the TP-Link Kasa KE100. This provides a hub and one valve, giving you smart control over a single radiator for the lowest possible upfront cost.

 

Do I need a hub for smart radiator valves?

Yes, in almost all cases. The vast majority of smart TRVs do not connect directly to your Wi-Fi. They require a brand-specific hub or internet bridge that plugs into your router to enable communication and app control.

 

How much do individual smart TRVs cost?

Individual add-on smart radiator valves typically cost between £50 and £70 each, depending on the brand and the features they offer.

 

Internal Links Included / Proposed

  • Smart Thermostat vs Smart TRVs: Do You Need Both? (Anchor text: "Smart Thermostat vs Smart TRVs: Do You Need Both?")

  • Smart Thermostats & Radiator Valves in the UK: Complete 2025 Buying Guide (Anchor text: "Complete 2025 Buying Guide")

  • Smart Thermostat Compatibility: A 5-Minute Check for Your Boiler (UK Guide) (Anchor text: "Smart Thermostat Compatibility: A 5-Minute Check for Your Boiler (UK Guide)")

  • Best Smart Heating Systems Under £150 (UK) (Anchor text: "Best Smart Heating Systems Under £150 (UK)")

  • Best Smart Heating Systems Under £250 (UK) (Anchor text: "Best Smart Heating Systems Under £250 (UK)")

 

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