Honeywell Homeexpert Digital Thermostat

Product rating
3.9 out of 5 stars
Product code:



Honeywell Homeexpert Digital Thermostat

Product code:
Honeywell Homeexpert Digital Thermostat



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  • Home Delivery Order by 7pm (2pm Sunday) for next day delivery.
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Product Details

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Product Details

Features and Benefits

The THR840 is a digital room thermostat that is more accurate than a mechanical room thermostat. Measurements from an electronic sensor are compared with your desired temperature and advanced control software is used to maintain the temperature in an energy efficient manner. ​​​

  • ECO Button for energy saving - ECO button provides timed temperature setback to reduce energy demand
  • System Control - heating and cooling functions from 5°C to 35°C
  • Precise Temperature Control - typically accurate to within 0.5°C for maximum comfort
  • Energy Efficient - uses TPI (Time Proportional & Integral) control which makes boilers operate more efficiently and provides close accurate control. It also has a self learning adaptive capability
  • Ideal for Combi-Boilers - volt free connections are ideal for use with combination boilers or heating zones
  • Easy to install - installation guide included, takes 15 minutes to install

Technical Specifications

Technical specification of Honeywell Homeexpert Digital Thermostat
Brand Honeywell
Minimum temperature range 5°C
Maximum temperature range 35°C
Model THR840DUK
Pack quantity 1

Help & Advice

BTU Radiator Calculator

Our BTU (British Thermal Units) calculator will help you to work out the heat requirement for your room, and recommend the number of radiators you will need to comfortably heat it.

What is a BTU?

A British Thermal Unit (BTU) is a measure of heat output from a radiator. Depending on the size of your room, the number and type of windows and what the room is used for, you'll need more or less heat. If you have a higher BTU requirement, it might be better to use more than one radiator to deliver the heat you'll need to a room. The total BTU output of several smaller radiators may meet your needs.

How do I choose the right radiator?

The BTU value of all our radiators is clearly labelled in-store and online, helping you find those which suit your requirements.

Step 1: Which room you are heating?
Step 2: What are the dimensions of the rooms?
Are you measuring in metres or feet?:
Length of room

Please enter the length of your room in your chosen units (metres or feet)

Width of room

Please enter the width of your room in your chosen units (metres or feet)

Height of room

Please enter the height of your room in your chosen units (metres or feet)

Step 3: What type of windows or doors are in the room?
Select all that apply:

Step 4: View your results

Your BTU result

How to guides

How to connect pipes and fittings

How to connect pipes and fittings

Pipes and fittings vary by home and by length, shapes and connectors. Thankfully, this is no longer a problem and there are lots of different solutions to make your pipework secure and reduce the risk of leaks.

Buying guides

Buyer's guide to plumbing tools

Buyer's guide to plumbing tools

Plumbing comes with a whole catalogue of specialist tools. If you're going to do the job, make sure you get the right ones.

Reviews 3.9  out of 5 stars

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