In this our third article on household heating let us suppose that you are quite determined not to abandon the charm and cheerfulness of your open fire. You say, and quite rightly that it forms a focal point in your living room in winter and that it is companionable and bright during the long winter evening. On these damp afternoons when the daylight disappears so soon, you put a match to your fire and the whole room brightens up. You say that when you have friends in for the evening

there certainly is something about an open fire that seems to stimulate conversation and gives a feeling of hospitality. In a large house, particularly the older type of house with high ceilings and large rooms some modern form of central heating is really necessary. This can give an even background wormth with an open fire for radiant heat and cheerfulness.

There is much more to this large subject than the purchase of boilers and radiators, it is absolutely essential to have the advice of a heating engineer. For the following information on central heating we are indebted to Mr. R. W. Talbot.

Central heating is the provision of a boiler or a warm air furnace in the basement or in a suitable room in a house or building and the distribution of the heat through pipes or ducts to the various rooms. The distribution with a system such as this has to be carefully designed by a Heating Engineer and the first step is to calculate the heat loss from each of the rooms. The plant is then designed so that the heating system will replace this heat loss in each of the rooms to maintain comfortable conditions. The types of central heating are numerous but we will refer briefly to each system as follows:

Low Pressure Hot Water Systems:

The low pressure system wtih cast iron radiators is the most commonly used central heating system for both domestic and commercial applications. The radiators are usually placed under the windows and the distribution piping system is concealed under the floor or in the ceilings and each radiator is fitted with a valve so that its heat input can be adjusted or so that it can be turned off.

Another system which is popular is the use of convectors and with these, a battery of tubes with closely spaced fins is used as the heating medium and this is controlled with valves as for the radiator. The unit is neatly covered in a sheet metal casing which can be built into the wall or stand slightly clear of the wall end the air from the room circulates through a slot at the bottom over the heater and out through the top grilles to warm the room. This is heating by convection as against heating by radiation as with cast iron radiators.

A revised form of" this convector heating is the skirting board heating which

is being installed in N.Z. In this case, the convector is a much shorter unit which tits at skirting board level.

Steam Heating:

Heating with steam is not normally used in homes in N.Z. today although it is still used quite extensively in industry. With steam, convectors are usually used for heating offices, etc., while unit heaters or projection heaters are used for heating large spaces such as workshops, factories, etc. The unit heater or the projection heater is a battery of finned coils encased in a sheet metal casing and fitted with a motor driven propellor fan which forces the circulation of air through the fins and distributes the air in the building.

Warm Air Heating:

With this system of heating, the warm air is distributed through the building with a sheet metal ducting system and the air is delivered into the room through neat grilles or diffusers. Usually a portion of this air is returned to the heating plant and is filtered and re-circulated Where air conditioning is called for the warm air system is usually incorporated and the air is cleaned by filtration, heated or cooled as required, and moisture is added so that a constant set of conditions is maintained in the building. This of course provides the best possible conditions for comfort and human respiration. Air conditioning is of course a very expensive installation as so much equipment is required to condition the air before it is distributed.

There are several methods of providing warm air heating for domestic pur* poses without putting in a very extensive plant as described above, but these only provide the heating side of the business. The automatically oil fired furnaces are available for mounting under the floor or basement with one outlet into the house and a number of installations of this type are being made in N.Z. today.

Concrete Slab Heating:

It is possible and very satisfactory to use heating cable embedded in concrete floor slabs. This form of heating is very economical of electricity and can be used in walls and ceilings as well as in

floors. A relatively low temperature will maintain an even warmth. It is also possible to install pre-cast plaster panels containing heating cable and these can be set flush with the rest of the standard fibrous plaster ceiling.

Alternatives to Central Heating:

If you want a very much simpler and less expensive form of background heating there are other types of heaters that can be used.

The new kerosene heaters are well worth looking at — a modern and much more efficient version of the old fashioned kerosene heater, slow burning and very reliable and quite fool proof.

As well as these there are all kinds of electric radiators. A type that heats oil circulating through pipes or through flat dimpled panels, are ideal for the nursery as they are so safe and can be used to dry the clothes. There are other electric heaters, some with fans, others are new versions of the old electric radiator but in every case look for a radiator that has the element well protected as safety is one of the most important factors in selecting your type of domestic heating.