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Winter warmth · Ireland

Electric Room Heater Running Cost Comparison

Which electric heater is cheapest to run depends on whether you need to warm one person, a bed or the whole room, how fast it loses heat and how long you run it.

Interactive tool

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A scenario-specific recommendation, per-evening and winter cost, room heat requirement, a full like-for-like comparison and how it compares with running your central heating.

Step 1 of 2Use · Room
  1. Use · Room, step 1
  2. Tariff, step 2

Use

Who needs to be warm?

Room

Length by width is close enough.

This sets the heater power the room needs. Judge it by how quickly the room cools once the heating goes off, and pick the draughty option for single glazing, open fireplaces or a north-facing room that never feels warm.

Nothing is saved. Your inputs are used only to calculate this result.

Personalised answer

Your result stays in view

Complete 2 short steps and this panel fills with your answer.

  • A direct answer to the question, in one line
  • The figures behind it, broken down
  • Practical next steps and the assumptions used

Every figure this tool uses comes with your result, beside its source and the date it was checked, together with a worked example and the assumptions behind it.

Before you begin

What affects room heater running costs

An 'eco heater' label is something the comparison can test rather than take on trust. It works out what the room actually loses at your insulation level, prices a heated throw, an electric blanket, a fan heater, an oil-filled radiator, a panel heater and an infrared panel on the same evening, and says which ones cannot keep up. It also prices the alternative honestly, putting the central heating beside them at Bord Gáis Energy's published gas rate, a national kerosene average, or your own electricity rate for a heat pump.

  • Measure length by width for a rough room area.

  • Choose ‘the whole room’ only when the air and the surfaces need to be warm, not simply one seated person.

Reading the answer

Understanding what each heater costs to run

A heater marked as too small only looks cheaper because it cannot keep up with the heat the room loses.

Where more than one heater can keep up, the comparison shows how far apart they really are on running cost, and what is left to choose on: speed, silence and comfort.

Common questions

Common room heater running cost questions

Is an oil-filled radiator cheaper than a fan heater?

It hinges on the heat your room loses, the hours you run the heater and your electricity rate. The comparison runs both in your room for the same evening and shows whether each keeps up and what it costs.

Get a result above and the full answer opens here.

Is a heated throw cheaper than heating the room?

It rests on the room it would be warming instead, and how much heat that room loses. The comparison costs each option in your room over your evenings, beside simply turning on the central heating.

Get a result above and the full answer opens here.

Every question the tools answer

Maintenance

What has changed in this tool

  1. 12 October 2026

    Version 2026-10-12.1

    The electricity rate the form opens on moves to the current standard 24-hour rate, between what Bord Gáis Energy and Energia publish from October 2026, so every Verdanyx page opens on the same bill. The worked example moves with it. Nothing in the method changed; only the figure the field opens on.

    Source for this change

  2. 29 September 2026

    Version 2026-09-29.1

    The like-for-like comparison is now drawn to scale per evening. A heater that cannot keep up with the room is labelled as such on its bar, so a short bar is never read as a good buy. No price or heat-loss figure changed.

  3. 1 September 2026

    Version 2026-09-01.1

    The central-heating comparison no longer rests on three undisclosed constants. Gas and oil now come from published fuel prices through a stated boiler efficiency, and a heat pump is priced from the electricity rate you entered rather than a flat figure that could only be right at one tariff. Gas and oil also swap places in the comparison, which the old anchors had the wrong way round.

  4. 25 July 2026

    Version 2026-07-25.1

    The result now compares against central heating. The question people actually ask is not “which plug-in heater?” but “is a plug-in heater cheaper than putting the heating on?”, and the tool could not answer it.