Start With the Building, Not the Heater

Before you spend a penny on a heat source, spend a weekend on insulation. A log cabin built from 45mm interlocking timber is, thermally speaking, a very handsome tent, and no heater on the market will overcome that. Add 100mm of rigid insulation between the roof joists, 50–75mm in the walls if the construction allows, and make sure the floor is both insulated and sealed. A well-wrapped cabin holds its warmth three or four times longer than a bare one, and that single fact decides whether a 1kW panel will do the job or whether you need a 5kW stove working hard all evening.

Then hunt draughts. Door thresholds, window frames, the junction where roof meets wall, and any gap around service pipes are the usual offenders. A tube of sealant and a few brush seals cost less than £30 and can shave a kilowatt off your requirement. Do this first and every heating decision afterwards becomes cheaper and simpler.

Electric Radiators and Panel Heaters

If the cabin sits within reasonable reach of the house's consumer unit, electricity is the least fussy route. There's no flue, no fuel store, no ash, and no combustion air to worry about.

• Oil-filled electric radiators — typically 1kW to 2kW, thermostatic and often programmable. They hold heat after switch-off, which suits a cabin used for a few evenings a week.
• Convector panel heaters — cheap to buy and quick to warm the air, but the warmth disappears the moment you switch them off. Fine for short bursts, poor for lingering.
• Run the supply properly. An extension lead across the lawn is not a solution. You want steel-wire armoured cable buried at around 600mm, sized for voltage drop if the run exceeds 30 metres, terminating in a small consumer unit with an RCD inside the cabin.

Expect to pay roughly £30–£60 per day of continuous use at current rates for a 2kW appliance. A thermostatic radiator that cycles rather than runs flat out will cost a good deal less, which is another argument for insulation.

Wood Burners and Multi-Fuel Stoves

Nothing beats a stove for cheer on a January afternoon, but stoves come with rules, and in the UK they are enforced.

• Check whether you are in a Smoke Control Area. If so, you need an exempt appliance and must burn authorised smokeless fuel or dry wood. Your local authority will confirm the status of your postcode.
• Burn seasoned logs below 20% moisture. A £15 moisture meter pays for itself; wet wood wastes most of its energy boiling water and coats your flue in tar.
• Installation is notifiable. Approved Document J covers hearth dimensions, clearances to combustibles (typically 150mm at the sides and more to the rear for a freestanding stove), flue height and permanent ventilation. Use a registered solid fuel installer and keep the completion certificate — insurers and future buyers will both ask for it.
• Fit a carbon monoxide alarm in the same room. Always. No exceptions, however well the flue draws.
• Provide permanent combustion air. As a rough guide, allow 550mm² of free vent area for every kilowatt of output above 5kW, and never block it in winter to stop the draught.

Infrared Heating Panels

Infrared panels warm people and surfaces rather than the air, which suits a cabin used in short bursts. A 350W to 700W panel mounted overhead or on the wall above a desk feels warm within a minute or two, and because it isn't heating the whole volume of the room it can be surprisingly economical for a workshop or home office. What it won't do is keep the fabric of the building warm, so the moment you step out of the beam the chill returns. Treat infrared as a spot-heating companion to a background source, not a replacement for one.

Ventilation, Condensation and Air Quality

Every heat source needs air, and cabins are far tighter than most people assume. A sealed hut with a stove burning inside is a genuine hazard: combustion consumes oxygen, and the products of incomplete burning are invisible. Permanent ventilation is a safety requirement, not a comfort compromise. If you fit a solid fuel appliance, size the air vent to the appliance and leave it alone.

Even without a stove, cabins sweat. Breathing, boiling a kettle and hanging up wet coats all release moisture, which condenses on cold surfaces and soon turns to mould behind furniture and along the base of walls. Trickle vents in windows, a couple of air bricks at opposite ends of the building, and a small extract fan for cooking will keep the structure dry. Dry buildings heat up far more readily than damp ones.

Never run a portable paraffin or unflued bottled gas heater in a sealed cabin. They produce large volumes of water vapour alongside carbon monoxide, and the two together are a miserable combination.

Off-Grid Options and Matching the System to the Use

Where there's no mains supply at all, a small solar array with a battery and inverter will comfortably run a few hundred watts of background heating, though heating is the hardest load to serve from batteries and expectations need to be modest. Bottled LPG drives radiators, stoves and catalytic heaters well, provided the appliance is room-sealed or properly flued. Diesel air heaters are popular for workshops: a 2kW unit typically sips around 0.2 litres an hour, running on kerosene or road diesel, and needs only a small exhaust through the wall.

Above all, match the system to how the cabin is actually used. A studio worked in daily wants insulation, background heat and a top-up source. A weekend retreat in the hills wants a stove and a well-insulated shell, with everything else as backup. Get the building right, keep the air moving, and the heating almost looks after itself.