notaguru wrote:It's a 1500W heater, exactly the same as a $12 heater from Walmart.
Are the LifeSmart watts somehow warmer? More comfortable? Cheaper? Greener?
Sometimes a watt is just a watt, and 1500 of them have precisely the same heating effect whether the source costs $109 or $12.
No, a watt is not a watt when it comes to heating. It's important to know that wattage measures energy usage, not the output capacity, which is measured in BTU, The way that electrical watt is converted to heat, and how that heat reaches you are important considerations. As a simple example consider an incandescent lightbulb. It definitely gets hot, but much of the wattage is used for light, so the electrical conversion to heat is not very efficient (in other words, don't use an EasyBake™ oven).
Heat is transferred to you in three different ways: Radiation, Conduction and Convection.
1) CONDUCTION: This is the most efficient, but arguably least practical. It means that the heat source has direct contact with your skin, so there is great transfer. An example is the electric blanket, which rarely uses more than 150 watts yet your entire body feels toasty. The flip side is that room remains cold, and other occupants in the room are not warmed. Blankets are also impractical if you need to move around, and in certain environments, i.e. bathroom or workshop. Conduction can also occur using thermal conductors such as metal in between the source and destination. This is the principle of heat sinks and water cooling, which take heat away from your CPU.
PROS:
- Silent
- Energy efficient since most of the heat is transfered directly to the taget. Usually under 150 watts
- Heating is fast, although not as fast as radiant heat
- Heat can be individualized; different people can have different temperatures
- A blanket's coverage is very adjustable. You can cover only the parts that are cold, and leave other parts uncovered. Some have intelligent thermostats where the feet, midbody and chest have individual sensors.
CONS:
- Not easily trasportable; you have to stay plugged in
- Cannot warm a room so it's not good for many situations, i.e. the bathroom or workshop
- Blankets require special care
- Some claim EMF hazzrd although current models emit very low levels
- Although the blanket constantly monitors itself for safety, if a fire does break out, it would be VERY near your body.
2) CONVECTION. This is a variant of conduction where heat is conducted through air molecules. Since air is needed, no convection occurs in a vacuum, i.e. space. It's the principle behind the Thermos™ bottle, where a vacuum layer shields the contents from the outside, thus keeping the contents hot or cold. The opposite result is used in convection ovens, where a fan circulates hot air around and inside foods, i.e. a turkey's cavity.
Any heater that has a fan uses convection. Basically, a surface in the heater gets hot and a fan blows that heat into the room. The simplest configuration is a wire that gets red hot through resistance, and a fan blowing on that wire to get the heat out. It's the principle behind a hair dryer. MOre sophisticated models use heating elements such as ceramic, often made into a honeycomb structure to increase surface area. An advantage of ceramic is that it stays hot longer after the thermostat turns off, saving energy.
Some convection heaters are passive and don't use a fan. An example is oil filled radiator from DeLonghi. It heats up internal tubes fill with oil which then warms the surrounding air. It's energy efficient because the oil stays hot long after the electricity is turned off. Just imagine standingg next to a large covered pot of hot water.
PROS
- Warms the room
- Gentle warm air current can be soothing
- On low, fan noise can be used as white noise
- Can be used for drying items. In fact, if you use it to dry clothes, the resulting increase in humidity is healthy and increses the apparent warmth of the room -- BUT MAKE SURE THERE IS ENOUGH SPACE BETWEEN THE ITEM AND THE HEATER TO AVOID A FIRE
- Can be placed in an attractive housing, i.e. a simulated fireplace
- Generally not a fire hazard since heating element is covered and usually unseen
- Usually pet and children safe since housing stays cool
CONS
- Inefficient since heat must warm air to reach you; not so useful if you stay on the couch reading or bed sleeping. In the case of the oil heaters, it takes time to heat the oil
- Slow to warm you
- In the case of oil heaters, you have to sit relatively close to feel the heat
- Uses 800-1800 watts so it may overload your circuit breaker
- Can be noisy, especially on high
- Fan and grille get dirty over time; needs maintence
- Motor means that more can break
- Needs clearance space to pull in air
3) RADIANT. Radiant heat, aka radiation, does not need air for conduction, and goes directly from the source to the object. The best example is sunlight, which reaches us despite the vacuum of space. It can be 32F yet your skin can still feel hot from the midday sun. Most radiant heaters use a reflective surface to focus the heat from a heating element onto the target. The element can be a simple wire, but most use quartz tubes. These tubes can get hotter since the wire is inside a vacuum enclosed by quartz, making them less likely to burn (you need oxygen to burn; it's why incadescent bulbs also use a vacuum). Cheap radiant heaters use a parabolic reflector resembling a radar dish. Quartz heaters use a concave surface.
PROS
- Energy efficient since the heat warms surfaces and not the air. I have a radianr heater that uses only 300 watts, and another that uses 400/800 watts
- Heat is instant. Your skin is warmed within seconds
- Silent and sturdy since there are no moving parts. However, mpact can break the tubes
- Good for warming surfaces, i.e. pipes. Some people have these aimed at pipes in the Winter to avoid freezing, making them turn on automatically <32F.
- Good for therapeutic warming of the body, i.e. the joints -- BUT DON'T GET TOO CLOSE!!!!
CONS
- VERY focused heat. Depending on placement, the heat may not reach the entire body. The further the heater, the wider -- and weaker -- the beam.
- Heat can be blocked. If you dog is between you and the heater, you won't feel the heat. But the heat can go through transparent objects like windows. Just imagine the heat beam like light.
- CAn be a fire hazard. The center of the beam can get very hot if close enough. Paper and cloth reaching the element can catch fire, i.e. fires ave been caused by quartz lamps.
- Heating element is exposed, although usually covered by a grille
- The bright red orange glow can be uncomfortable to the eyes. this is especially true in a darken room, i.e. while sleeping or watching TV
- The heat can be uncomfortable to those who don't like sunlight
