First winter tramping, I idled. Engine on low revs, heater running, cab warm, slept fine. Cost a fortune in fuel, smelled of diesel by morning, and would have been a £40 Fixed Penalty Notice at any services with a no-idling enforcement sign — which some do and some don't, but the law applies regardless of whether there's a sign.
Second winter, I tried the 12-volt blanket and a down sleeping bag. Better than nothing. Still woke up at 3am cold.
Third winter I fitted a diesel parking heater. Took about four hours in the depot car park on a Saturday, cost around £250 for the unit and fittings, and I've never had a cold night in the cab since. Wish I'd done it year one.
What the idling law actually says
The Road Traffic (Vehicle Emissions) (Fixed Penalty) (England) Regulations 2002 prohibit leaving a vehicle engine running unnecessarily when it's stationary. The fixed penalty is £20 in England, doubling to £40 if you don't pay within a certain period — though local authorities can set different amounts up to £80. Scotland and Wales have their own provisions.
The enforcement: local authority officers can issue fixed penalty notices. Most don't patrol truck stop car parks. But some motorway services operate under management agreements that include this, and DVSA officers are aware of it. The primary enforcement risk is in urban areas and urban delivery situations — waiting outside schools, residential areas, city centre delivery bays.
The exception that matters for HGV drivers: the law specifically allows idling where it's necessary for the operation of the vehicle. A refrigerated trailer running its TK or Carrier unit to maintain temperature is not 'unnecessary' idling — the engine is running for an operational purpose. That's separate from running the cab engine for warmth.
The other thing drivers get wrong: idling to charge the vehicle batteries before a cold morning start. That's arguably necessary operation rather than warmth idling — but if you get into the habit of a long idle for warmth and call it 'battery charging' if anyone asks, you're on thin legal ground. Get the parking heater instead.
Diesel parking heaters: what they are and how they work
A diesel parking heater — the Webasto Air Top range and the Eberspächer Airtronic are the two most common — is an independent combustion unit. It draws a tiny amount of diesel from the vehicle's fuel tank (we're talking a fraction of a litre per hour), burns it in a sealed chamber, and blows warm air into the cab via ducting. The engine is off. The cab is warm. You're using maybe £1-2 of fuel for an eight-hour rest period.
The unit runs from the vehicle's 12V battery. It draws current to run the fan and the control circuitry, but significantly less than running the engine at idle. Most installations include a second auxiliary battery to handle the heater overnight without running the starter battery flat. If you're running a 12-volt inverter setup for a kettle and a phone charger as well, size the auxiliary battery appropriately — a 100Ah battery is minimum if you're also running other 12V loads overnight.
Fitting: the unit goes somewhere with good airflow, usually under the bunk or in the nose of the cab if you can route the ducting. It needs a fuel feed (usually tapped off the main fuel line or an in-cab auxiliary connection), an exhaust pipe to the outside, an air intake, and a 12V power feed. If you're not confident with 12V wiring and diesel fuel lines, get it fitted properly — a bad installation can cause carbon monoxide issues, though sealed combustion units are designed to prevent this.
In service vehicles, many trucks from Scania, Volvo, and DAF have factory parking heater options, or provisions to fit one easily. Check before you buy a used cab — there's sometimes a factory provision already there that just needs a unit dropped in.
The 12-volt setup that works for winter nights
Beyond the parking heater, a few things that made a real difference to winter nights:
A proper 12-volt kettle — not the cheap ones that take twenty minutes. The Ring RTK2 or similar. Two minutes for a cup. Buy decent instant coffee and you're sorted for the 2am wake-up.
A good sleeping bag with a synthetic fill rather than down. Down loses its loft when it gets damp from condensation, and cabs get damp overnight when people are breathing in them. Synthetic fill is more forgiving. Something rated to -10°C is probably more than you need for a UK winter but it means you're warm on the coldest nights rather than 'warm enough'.
Blackout curtains between the cab and the sleeper. They cut draughts from the cab glass, reduce heat loss, and block depot yard lights that make it hard to sleep before your rest period's even started. Most trucks have the fitting points already there — the curtains are cheap and the difference is noticeable.
Condensation is a real issue in a sealed cab with one or two people breathing in it. A microfibre cloth kept in the cab and a quick wipe of the windows before you pull out in the morning stops it becoming a vision or defect issue. Some drivers leave the demist running for five minutes with the engine warmed up before setting off. Either works.
Mains hookup sites: where they exist
A growing number of dedicated truck stops have mains electric hookup points for HGVs — same concept as a motorhome pitch. You plug in, run your electric heater, charge your devices, and don't touch the fuel tank or the battery. A small number of motorway services have started offering these as the industry pushes toward better driver welfare.
DIRFT Rugby has facilities. Some of the larger dedicated HGV parks — Truckstop England at Normanton, Euro Garages at various sites — are developing mains hookup capability. The provision is inconsistent and not yet at a point where you can plan a tramping week around it, but it's worth knowing the sites that offer it on your regular routes.
For winter nights where you're at a mains hookup site: a 240V convector heater in the cab is significantly more comfortable than a diesel unit, quieter, and puts no load on the vehicle's own power systems. A 1kW convector on a hookup pitch is around 10-15p per hour. Cheaper than diesel, less noise, no exhaust concerns.
Layby and non-truck-stop overnights
The reality of tramping is that not every night is at a proper truck stop. Laybys, industrial estate car parks at a customer's instruction, service road overnights. No hookup. Sometimes no lighting. These are where the parking heater setup earns its keep.
For layby overnights: the parking heater handles warmth. The blackout curtain handles light. The main safety consideration is CO — diesel parking heaters vent externally and are sealed combustion, so CO risk is low if installed correctly. Never run an unvented heater — camping stoves, propane heaters, anything that vents into the cab interior — in a sealed space. That's not theoretical risk. It's killed drivers.
The Mobility Package I rules on weekly rest mean you shouldn't be taking a regular weekly rest in a layby or unsecured location anyway — those rules require suitable rest facilities for weekly rest periods. For daily rest, a layby is not prohibited, but it's not ideal. If you're finding yourself regularly forced to overnight in non-truck-stop locations, it's worth raising that with the transport manager or agency — that's a driver welfare question as much as a comfort one.
ShiftOwt doesn't sort the cold nights out. But if you're tracking shift availability and rest compliance in one place rather than three notebooks and a WhatsApp, it frees up some headspace. £5.99/mo for drivers.