The FitOutPontoon does not recommend the use of this type of heating under any circumstances on a narrowboat.

Available from most high street retailers these fall into two types, the radiant bar and the heat lamp.

Bar, or strip, heaters are commonly found in small rooms such as bathrooms and work by current flowing through a resistive element. Electrical energy is converted to heat energy which is often reflected into the space by a mirrored plate behind the element. They provide fierce, localised heat.

Electric fan heaters work on the same principle of electrical resistance except the element is usually encased in a plastic housing and a fan forces air across the element into the room. They dry out the air, circulate dust and are generally unhealthy.

Heat lamps produce an excessive amount of infra red radiation which heats the body. They come in a range of shapes & sizes and can be wall mounted, free standing or supplied as a screw-in bulb. Despite being more efficient than bar heaters they can still pose a burn hazard to skin or nearby items.

For safety’s sake, we do not condone the use of these heaters under any circumstances on a narrow boat.

If we do need portable electric heating for temporarily supplementing a permanently installed heating system then these heaters are by far and away the safest for a narrowboat.

As with radiant heaters, heat energy is generated through resistive elements. However, in the case of these radiator style heaters, the element is usually encased in an oil or gel filled metal chassis. In fact, very much like an electric kettle with an enclosed metal coil in the base which heats the water.

The oil or gel in the heater heats up, heat is radiated from the metal casing and the air in the space becomes heated. These heaters hold on to their heat so even when switched off they will continue to radiate heat.

In the case of oil or gel filled column heaters, although the primary heat is radiant the air circulating between the columns produces convective heat.

Whilst clearly much safer than exposed element radiant heaters, these radiators are still power hungry. Ideal for use with a shore supply of 230V they are silent in operation. If running from an inverter on your narrow boat, you will need to be sure the power output of the battery/inverter combination can handle the current draw of the heater. Any electrical item with an element will be a heavy load on a DC to AC system. If it is running through a dedicated 230vAC system then all you will have to keep an eye on is the electric meter spinning round.

This type of heating can best be described as a radiant system. Installation involves laying a mat of embedded wires under the floor. Control comes from a thermostat and often installations can be zoned for different areas.

This type of system is still fairly uncommon on narrowboats. Traditionally, solid fuel stoves supplementing diesel fired hydronic systems offer better efficiencies and more appeal. As technology advances we may see more underfloor installations but two issues currently prevent more widespread fitting.

Primarily, the cost and awkwardness of generating a constant supply of domestic 230v electricity and  lower thermal efficiencies mean that on the whole underfloor heating needs careful consideration before being adopted as a primary heating system.

Those systems that are suitable come in kit form with heating wire, or elements, enclosed in a foil mat. This mat can be laid directly onto the ply subfloor and then overlaid with tile, carpet, solid wood or engineered wood floor coverings. All that is required is a constant 230V supply to the thermostat. Thermal losses can occur into the bilges so this needs careful consideration. Also if installed under tile or solid flooring, the flooring has to be removed should anything go wrong.

The requirement for fixed open ventilation on most narrow boats means that a subtle background heat can struggle to be effective however, there may be value in having a mat under the floor in a cold bathroom.

Whilst ideal if you have a reliable and inexpensive shore power supply, any 230V electrical device running off a 12V to 230V invertor will drain the domestic battery bank. One manufacturer of this type of heating quotes a power consumption rate of 140 watts per m² for the foil matting.