Dimplex DuoHeat Radiators

Removing a clapped out storage radiator is not my idea of a good day out. I knew I would need a good vacuum cleaner and a dust sheet. If I had a mate (instead of being Billy no mates) we probably would have picked the whole thing up and slung it on a skip in one piece but as it was I had no option but to un-brick it. There couldn't have been a greater contrast between dismantling the old one and fitting the new one. The design makes it very easy for the installer but you still have to read the instructions for the small details. For example it is important to open the box at the bottom so you can gain access to the feet. These need to be fitted before you remove the box. The feet simply clip into place.


Installing Duoheat should take between 2-3 hours.

  • 1 of 12 |

  • 2 of 12 |

  • 3 of 12 |

  • 4 of 12 |

  • 5 of 12 |

  • 6 of 12 |

  • 7 of 12 |

  • 8 of 12 |

  • 9 of 12 |

  • 10 of 12 |

  • 11 of 12 |

  • 12 of 12 |

Once you get the heater on its feet and against the wall you can fix it securely before you remove the cover. There are two elongated fixing holes in the in the back panel. I would have preferred another in the middle and I could have drilled one because I was fixing to one of those horrible modern plasterboard walls with no studwork. Dimplex provides fibre Rawlplugs (plastic goes soft with the heat) but because of the rubbish wall I fitted self tapping metal plasterboard screws. It seemed to give a secure fixing but it can never be stronger than the wall itself.

Once the heater is secure you can build it up with the bonded magnetite heat retention cells (bricks in the old language). There are far fewer screws in the Duoheat so the cover comes off very quickly. The low voltage plug in connection means that you can remove it completely while you carry out the build up. In theory the incaloy elements in the storage cells lift up so they can be gently laid forward. The middle one came out fine but the other two felt tight on the cable so I left them where they were rather than fiddle about and I slipped the cells in behind from the middle.

The front panel has a thin film radiant element in an ultra slim casing to give rapid warm up for peak time and top up. The Smart Heat manager automatically controls heat levels to optimise inputs to match room temperatures. If the room is well insulated and draught proofed the heat input is reduced to match it so the potential for savings is inbuilt and Dimplex claims that you can save up to 10% when compared to the old style storage radiators that relied upon draught control alone.

Another big improvement is the pre-wired flexes labelled up for off peak and standard rate. The standard 4th wire (black) in the standard (peak) supply is there for the optional programmer room stat which can control the whole house to turn the front panels on from a central stat and timer rather than the childproof control on top of the heater.

When it comes to replacing those incaloy elements the job will be a lot easier than it was on the heater I took out. In truth I could have done just that but I talked the householder into a new heater because it not only looks better but will save energy and give them greater control over their heating. It was an offer they couldn't refuse.

Energy saving features

  • Patented 'smart' heat manager automatically controls output level from each heat source, optimising controllability and economy.
  • Single, simple to use and understand electronic user control, with child lock facility:
    – Electronic room temperature control allowing user adjustment of heater output.
    – User configurable electronic automatic input charge regulator.
  • Energy-efficiency savings of up to 10% compared with traditional off-peak electric heating systems, recognised by SAP2005, the tool for showing compliance with Part L of the Building Regulations.
  • Compatible with Dimplex 4-zone, wall mounted pilot wire and mains borne signalling multi-heater programmers.

Dimplex Duoheat Range

Model Duo300i Duo400i Duo500i
Height 712mm 712mm 712mm
Width 600mm 830mm 1060mm
Depth 130mm+10mm 130mm+10mm 130mm+10mm
Weight 65kg 94kg 124kg
Nominal Output 0.7kW 1.0kW 1.4kW
Charge Acceptance 9.1kWh 13.65kWh 18.2kWh
Background/Input 1.3kW 1.95kW 2.6kW
Radiant 0.28kW 0.34kW 0.39kW