Below is a comparison between natural gas radiant heaters and electric radiant heaters. The objective is to heat a 4.0 x 6.0m rectangular outdoor area totaling 24m2. The area in question only has one wall enclosed along a 6.0m section with a flat roof covering the entire area at 3.0m above the floor.
One 27Mj/3 Tile Natural Gas Tungsten 300series will heat approx 89m2. Therefore to heat 24m2 a total of 3 x 27Mj heaters would be required in a mildy windy environment (winds 8 12km/h).
Operating CostsEach unit outputs a maximum of 27 Mj/h. Multiplied by 3 units comes to a total output of 81Mj/h. The consumption of one MJ/h costs around $0.03. Therefore $0.03 x 81 MJ equals $2.43 per hour. Design ConsiderationsThe 27Mj/3 Tile Tungsten 300seires heaters have been specifically chosen for this particular area. The main reason behind this is that if the higher capacity 45Mj/5 Tile heaters were installed, customers seated closest to the heaters would be subject to excessive heat and feel uncomfortable. As can be seen in the first diagram the heaters are able to proejct heat out from the wall a total of 3.0m during mild winds (812km/h). With no wind the entire 4.0m width could achieve coverage from the 3 heaters and enough overlap to cover the entire 6m length.
Natural Gas Summary Unit costs 27MJ/3 Tile  Tungsten Natural Gas Heater with Electronic Ignition @ $1,515.25 each. Total costs @ $4545.75 Incl. GST.  Heat deflectors @ $266.00 each. Total costs @ $798.00 Incl. GST. Specs/Prices: Tungsten 27Mj/3 Tile Natural Gas Heater Total costs $5,343.75 Incl. GST + Installation Running costs approx: $2.43 per hour.

One 2400W ERH Radiant strip heater will heat approx 56m2. Therefore to heat 24m2 a total of 4 x 2400W strip heaters would be required in a mildy windy environment (winds 8 12km/h).
Operating CostsEach unit outputs a maximum of 2.4 kW/h. Multiplied by 4 units gives us a total output of 9.6 kW/h of heating performance. The consumption of one kW/h costs around $0.28. Therefore $0.28 x 9.6 kW equals $2.69 per hour. Design ConsiderationsThe 3.0m ceiling height is just outside the optimum heating range for the ERH strip heaters. As can been seen in the above diagram the heaters have been suspended down with dropping brackets to a more suitable height of 2.6m above floor level (400mm drop). As can be seen in the first diagram the entire area is able to achvie coverage. At 2.6m the heaters are able to throw/project heat a maximum distance of around 2.8 meters  therefore reaching the floor. Ideally anyone standing or seated around tables or lounges will be able to absorb the heat and feel quite comfortable. Electric Summary Units costs OHERH2400W strip heater @ $629.10 each. Total costs @ $2,516.40 Incl. GST.  Dropper brackets @ $120 per set. Total @ $480.00 Incl. GST. Specs/Prices: OHERH2400W Strip Heater Total costs $2,996.40 + Installation Running costs approx: $2.69 per hour 
