They usually come with a 1500W setting.
A ceramic heater is going to be your best bet. They are small, use little energy, and actually have a much more powerful output of heat than most heaters.
There isn't that much of a difference really. Strictly speaking the ceramic heater is also a resistance coil heater, the difference being that the coil is embedded in the ceramic, giving a bigger heat-emitting surface. In heating costs they'll be the same. But having a bigger emitting surface operating at a lower temperature may give a "softer" heat. A bit like filling a bucket of water from a shower head or a hose. It'll take just as much water, and take the same amount of time, but the wider spray from the shower head will hit softer than the jet from the hose.
Vornado is the brand of heater that is the most energy efficient. If used properly, Vornado heaters can heat just as well as a larger heater, for a much lower cost. They are small, portable, and can heat large rooms. Some of them even have thermostats or timers to increas efficiency.
Cool touch heaters are made of ceramic and aree very safe, while mica radiators are hot to the touch but produce much more heat.
Strictly speaking the ceramic heater is also a resistance coil heater, the difference being that the coil is embedded in the ceramic, giving a bigger heat-emitting surface. In heating costs they'll be the same. But having a bigger emitting surface operating at a lower temperature may give a "softer" heat. A bit like filling a bucket of water from a shower head or a hose. It'll take just as much water, and take the same amount of time, but the wider spray from the shower head will hit softer than the jet from the hose.
small amount
The efficiency of a water heater is measured by its Energy Factor (EF), which indicates how much of the energy input is converted into hot water. Factors that can affect a water heater's performance include the type of fuel used, the size and design of the heater, the temperature setting, and the frequency of maintenance.
Turning off the water heater when not in use can save energy, as the heater does not have to constantly maintain a set temperature. However, frequent on/off cycles may increase energy consumption, so finding a balance that works best for your household is recommended.
lots
The Amana 12000 BTU Energy Star Room Air Conditioner with 11260-BTU Heater is good.
Ceramic bowls for kitchen, with thorium, doesn't exist.
I would not try to heat a tank any larger than 8 gallons with a small 50 watt heater. The difference in price between a 50 watt and a much more usful 150 watt heater is not much. I'd check things out before I got a very small heater that may have to work very hard to do its job.