Coleman ProCat Electric Utility/Portable Heater
The Coleman ProCat runs on propane and two D-cell batteries. The batteries power a forced-air fan that circulates warm air, and the propane provides power to the heater. The heater can operate without the fan, but not vice-versa. This heater provides 3,000 BTUs (British Thermal Units) per hour; it is among the most compact portable space heaters on the market, at 12 inches wide, 16 inches deep, and 11 inches high. It weighs just over 7.5 pounds. The heater will operate for up to 8 hours on a 1-pound canister of propane, and the fan will run for up to 18 hours on two D-cell batteries. This heater costs between $100 and $120 at most retailers.
Mr. Heater Big Buddy
The Big Buddy has more features and settings than the Coleman ProCat, is larger, and can produce more heat, but is less portable. It offers three heat settings — 4,000, 9,000 and 18,000 BTUs per hour. This heater also runs on propane and has a battery-powered fan. The fan requires four D-cell batteries. It has a Piezo starter that does not rely on electricity to operate. The Big Buddy weighs about twice as much as the Coleman, about 15 pounds. Its dimensions are 17 inches wide by 10 inches deep and 17.5 inches high. The heater will operate for 1.5 to 220 hours, depending on the size of propane tanks you use. Hookups are installed for up to two propane cylinders. Using two 20-lb cylinders, this heater can heat up to 400 square feet. A 1 lb. propane cylinder will provide 1.5 to 6 hours of heating. This size cylinder is the largest approved for in-home use. Two 1 lb. cylinders will provide power for 3 to 12 hours. One or two 20 lb. cylinders can also be attached, with the addition of the optional propane hose assembly designed for this heater. However, the 20 lb. cylinders are not recommended for use indoors! The Big Buddy retails between $110 and $160.
Sengoku Omni Radiant Portable Kerosene Heater
The Sengoku Omni runs primarily on kerosene, but uses 2 D-cell batteries for its starter. The Omni Directional Radiant Heater is designed to heat up to a 20 square foot room, and provides heat for up to 14 hours on a full tank. It produces 10,000 BTUs per hour. The Omni uses a battery-operated push button ignition and manual shut off. It is 15 inches round, 23 inches high, and weighs 18 pounds. This product retails for about $200.
NU Warm Stone Portable Heater
The NU Warm Stone Portable Heater is a personal hand warmer rather than a space heater, but runs entirely on battery power. It contains a rechargeable lithium battery and is chargeable off a USB cord connected to a computer. The battery is designed to last for at least 500 charges. The NU Warm Stone is intended for personal use. It has two heat settings, of about 102 degrees Fahrenheit (with a battery life of about 7 hours) and 109 degrees Fahrenheit (with a battery life of about 5 hours). It weighs only 70 grams and is 84 by 62 by 19 millimeters, made to fit in your pocket. The unit can take 10 minutes to an hour to reach its highest temperature, depending on environmental conditions. Each unit retails for about $30.