Thermometers are a must-have tool for balancing radiators, but with so many options out there it can be tough to choose the right one. We will have a look at the all singing all dancing heating probes kit which will have you covered for heating installations and servicing. In your profession, it is important to know how hot or cold something is, so check out the best thermometer for balancing radiators!

Radiator with TRV

Best Thermometer for Balancing Radiators

We all know that balancing radiators can be a pain in the backside, especially if you want to ensure you are accurately getting that 12-degree drop. We have found the Testo Smart Probe to be the best tool for the job and it is reasonably priced.

Testo SMART Probes Heating Set Temperature Meter

The Testo SMART probes heating set (amazon link – opens in a new tab) is a compact kit containing three measuring instruments for carrying out your most important tasks involving heating systems. It is paired with an app that can be added directly to your mobile device which helps you to work more easily and efficiently. The measurement menus include pressure drop tests with alarm function and non-contact IR temperature measurements for image documentation that includes measuring value and the location of the measuring spot.

Measurement data reports can be emailed as PDF or Excel files directly from your phone or tablet!

What’s Included

  • Mobile application
  • 1 x Testo 115i clamp thermometer
  • 1 x Testo 510i differential pressure monitor
  • 1 x Testo 805i infrared thermometer
  • 1 x Carry Case
  • 9 x micro AAA batteries
  • Hose set (Ø 4 mm and 5 mm)
  • Hose adapter
  • Calibration protocol
Testo Smart Probes


  • Measures surface temperature, flow & return temperature, and pressure
  • Bluetooth transfer to smartphones/tablets
  • Free Testo Smart Probes App performs calculations and analysis
  • Results are shown on smartphone/tablet screen
  • Specialised menus for specific tasks
  • Data saved in Excel or PDF report with pictures
  • Long battery lives (30-250h)
  • 2-year warranty on all instruments

What I Like

What I liked about this set is that it includes three instruments, so you have everything you need for installations and servicing right out of the box, and it made balancing radiators an absolute doddle. All of the instruments are well-made and durable so they should certainly last as long as you look after them.

The winning feature for me is the app that can be downloaded onto your device, which makes things much more convenient as I was able to read all of the results straight from my phone.

What I Don’t Like

What I don’t like is the fact that the instruments run on disposable batteries, I would prefer them to be rechargeable. I hope that this is something that Testo addresses in the future. I also feel that the carry case could be a little better quality but that is really just nit-picking. This is a great tool


Having tested the Testo SMART Probes Heating set, I can say that I am massively impressed, and my wife will tell you that is not an easy thing to do. Whether you are installing a new heating system or just carrying out your annual service, the Testo set will make a great addition to your toolset and in my opinion, it is the best thermometer for balancing radiators.

Frequently Asked Questions

How do you measure the temperature of a pipe?

Using the Testo smart probes, you can attach the clamp thermometer to the pipe and the Bluetooth app will transmit the temperature data directly to your mobile phone.

Can the reading be read remotely?

Yes, the Bluetooth app can be read up to 10m away.

Can the probes be bought separately?

Yes, each of the probes in the set is available individually so if you need one or more spares, you can go ahead and get them.


Lee Pearce is not just a master plumber; he’s a veritable Plumbing Wizard. With over 30 years of experience in the trenches of pipes and drains, Lee has become the go-to sage for DIY plumbing, saving homeowners thousands in potential call-out charges. As the founder of Plumbing Wizard, he’s dedicated to demystifying the complexities of home plumbing, offering easy-to-follow advice that stands the test of time and pressure. His online blog is a treasure trove of tips, tricks, and tutorials that empower everyday individuals to take charge of their home’s plumbing health. Lee’s practical wisdom is not just about fixing leaks; it’s about imparting confidence and self-reliance. When he’s not writing or elbow-deep in a plumbing project, Lee is passionate about educating the next generation of DIYers, ensuring that practical skills are passed down and preserved.

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