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300W infrared heater under a desk

Updated: 22 October 2026

Your house is warm enough overall, but your legs are cold at the desk. A 300W infrared heater under desk search should not start with 3–8 m², because that figure is a tiny-room wall panel, not heat at a seat. Energy Saving Trust notes you may feel comfortable in view of infrared while air elsewhere stays cooler. Electricity costs more per unit than gas, so this is a top-up. The [300W infrared heater comparison](/hub/heating/300w-infrared-heater) lists four panels. Only one prints an under-desk job. A qualifying purchase through our amazon.co.uk links can earn us a commission at no extra cost to you.

Your house is warm enough overall, but your legs are cold at the desk. A 300W infrared heater under desk search should not start with 3–8 m², because that figure is a tiny-room wall panel, not heat at a seat.

Our top picks

Hocosyme Hocosyme UK-T-300W

Best overall

Hocosyme Hocosyme UK-T-300W
5.4/10about £69.99
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Byekalt Byekalt C-WK-300W

Rank 2

Byekalt Byekalt C-WK-300W
6.8/10about £79.99
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Könighaus Könighaus under-desk

Rank 3

Könighaus Könighaus under-desk
4.2/10about £162.00
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On this page
  1. 1.Heat at the seat, not heat for the room
  2. 2.The 300W panel in this set that states that job
  3. 3.Clearance under the desk
  4. 4.What it costs to leave it on

Heat at the seat, not heat for the room

Under-desk use is personal heat for legs and feet while you work. Success is radiant warmth on your shins and knees, not a thermostat three metres away at 21 °C. A short top-up is not a reason to leave 300 W running all day. Reject 3–8 m² as the test. Hocosyme and Byekalt print small-room coverage for a wall mount. Hocosyme GL prints 3–8 m² and 5–8 m² in conflicting fields. Sliding those under a desk borrows a room heater for a seat, without the stance Könighaus describes, and without proof the gap is safe around bags and castors. Room picks are on the best 300W infrared heater page.

The 300W panel in this set that states that job

The Könighaus listing at £162.00 describes localised heat for legs and feet, not an entire room, and it prints no square-metre figure. It is freestanding at 16.5 cm deep, 52 cm wide and 56 cm high, and 4.5 kg, with an on/off switch and no thermostat, remote, or timer named. IP44 is in the bullets. That is not a bathroom heater. Zones are on the 300W infrared heater bathroom page. amazon.co.uk shows no review line for this ASIN, so you are buying from the listing text and the photos. Do not import coverage lines from another language site onto this UK listing. Herschel’s 220 W desk unit, from about £199, is a different wattage. The cheapest 300 W wall panel is a room story, not this job.
Hocosyme Hocosyme UK-T-300W

Testsieger

Hocosyme Hocosyme UK-T-300W
5.4/10about £69.99
View offer

Clearance under the desk

Do not cover the face or bury the panel in cables. Other panels in this set claim up to 120 °C on the face, which burns skin or fabric that touches it. Herschel’s instructions for a different 220 W under-desk unit ask for the feet to be used, no cover, a surface up to about 90 °C on that product, and at least 300 mm from objects in front, including bags. That 300 mm is Herschel’s manual, not a Könighaus measurement. It still shows why a panel against a computer tower, a bag, or the chair lift is a bad idea. Route the lead so the chair does not catch it. Switch off when you leave. Do not run it where someone could fall beside an exposed hot face.

What it costs to leave it on

At 26.32 p/kWh on the Ofgem direct-debit rule of thumb for 1 October to 31 December 2026 in England, Scotland and Wales, with VAT off electricity in that window, 300 W at full power is about 7.9 pence per hour and about 32 pence for four hours. That is the same load whether the panel is under a desk or on a wall. An on/off panel makes it easy to leave full power running through a long call. Switching off at breaks is part of controlling the running cost. Skip Könighaus if you needed a weekly schedule or a room-sized claim. Skip the wall panels if the seat was always the plan. Skip bathroom assumptions drawn from IP44 on a desk listing.

Common questions

Will a 300 W panel warm my legs without heating the room?
It can warm legs in the beam if you sit in line of sight. It will not reliably warm the air in a large room. Success at a desk is warmth on your shins and knees during the session, not a thermostat reading of 21 °C across the room.
Which listing in this set actually says under a desk?
Könighaus at £162.00, with legs-and-feet language and no square-metre figure. It is freestanding and on/off only, and the listing has no review line. The wall panels print a small-room story instead. Use the UK bullets, not another site.
Is 3–8 m² the right test for a desk heater?
No. That is a wall-panel room guide on the Hocosyme and Byekalt listings. Under-desk success is what you feel at the seat. The portable Hocosyme also conflicts between 3–8 m² and 5–8 m², which is still a room claim.
How much does four hours at full power cost?
About 32 pence at 26.32 p/kWh for 300 W, direct debit, from 1 October to 31 December 2026 in England, Scotland and Wales, with VAT off electricity in that window. A full-power hour is about 7.9 pence, under a desk or on a wall.
How close can the panel sit to my legs, the chair, and bags?
Keep fabric, paper, and clutter out of the radiation path. Herschel’s 300 mm example is from another model’s manual, not a Könighaus spec, but a tight gap is still risky beside a hot face. Do not jam the panel against a bag, a computer tower, or the chair lift.
Is an on/off switch enough for this job?
It can be enough for a personal top-up if you switch off when you leave the seat. It is a weak way to heat a room all evening, because the panel stays at 300 W until you switch it off. No thermostat, remote, or timer is named on the Könighaus listing.

Related pages

How to use a 300W infrared heater

300W infrared heater buying guide

300W infrared heater

300W infrared heater bathroom zones, IP and sockets

Best 300W infrared heater: schedule, price, or desk

Sources

Public UK sources named below. amazon.co.uk prices, stars and review counts on these four listings were taken from the listing files read on 20 October 2026. Page updated October 2026.

  1. Ofgem price cap unit rates, 1 October to 31 December 2026 (retrieved 20 October 2026)
  2. Energy Saving Trust, infrared heating explained (retrieved 20 October 2026)
  3. IET Section 701, locations containing a bath or shower (retrieved 20 October 2026)
  4. SELECT bathroom guide (retrieved 20 October 2026)
  5. NICEIC bathrooms and electrics (retrieved 20 October 2026)
  6. Electrical Safety First, plugs and fuses (retrieved 20 October 2026)
  7. GOV.UK, placing energy-related products on the UK market (retrieved 20 October 2026)
  8. Herschel Select XLS installation manual (retrieved 20 October 2026)