Oily Rag: Up the heat not the cost

Choosing a heater is about as confusing as it can get. The secret is to understand a little about the different types of heaters, then buy one that suits your needs and your oily-rag pocket.

There are three types of heater to consider: radiant and fan heaters, oil-filled or convection panel heaters, and climate-based heating systems.

Radiant and fan heaters use an element and a reflective surface to provide spot heat, some have a fan to propel the heat. They are as convenient as they are portable and cheap to buy, but (there is always a "but") they are inefficient and therefore expensive to use. Natural-gas radiant heaters are cheaper to operate, but if one takes into account the additional cost and shorter life of gas appliances, and their need for regular maintenance, the savings are dubious.

Oil-filled or convection panel heaters are passive heaters that gently heat the air. They do not provide a blast of hot air (as radiant and fan heaters do) but are an excellent way of heating a room. Most come with a thermostat and timer.

Thermostats control the amount of power your heater uses by switching on and off to maintain your desired room temperature. Timers automatically turn your heater on and off at times that suit your needs. In other words they use less power and give you more control over room temperature at the most efficient times.

Climate-based heaters are in effect air-conditioning units as they pick up the natural heat from outside your home and pump it inside. In summer, they work in reverse to cool your home.

The advantage is they are cheap to run, costing about half as much as other heaters, but they are expensive to buy.

To summarise, if you want to heat a room look at an oil-filled type heater. If you want a quick blast of hot air, then a standard radiant heater is for you. Those who don't mind spending big bucks up front should look at a climate-based heating system.

Having decided on the type of heater that best suits your needs, the next task is to decide the right-sized heater for your room. This is not all that difficult to calculate.

Heaters come in different kilowatt sizes.

To determine the number of kilowatts you need, measure your room in cubic metres and multiply by 35.

If your room has a floor area of 6 x 4m and a 3m stud height, then it measures 72cu m. It takes 35W to heat a cubic metre so multiply 72cu m by 35W and you get 2520W, or 2.5kW ... so you will need a 2.5kW heater.

Measure one of the rooms in your home to do the calculation yourself.

Step 1. Length x width x height = cubic metres of room space.

Step 2. Cubic metres of room space x 35W = total watts required.

Step 3. Total watts required divided by 1000 = kilowatt heater required.

Here are a few other space heating tips

For those who have water-heated radiators, pin or staple kitchen foil behind the radiator. This deflects the heat into the room rather than allowing it to heat the wall.

Use a timer on oil heaters. Have it turn the heater on a couple of hours before you get up in the morning.

Reflectors in heaters should be kept clean and bright.

Using an open oven as a space heater is expensive and downright unoily-raggish.

Do you have a favourite winter tip you would like to share with readers? Send it to us at www.oilyrag.co.nz or write to Living off the Smell of an Oily Rag, PO Box 984, Whangarei.

Frank and Muriel Newman are the authors of Living Off the Smell of an Oily Rag in NZ.