It is efficient for a a room size of 10 x 15.
Any heater that has the Energy Star label will be very energy efficient. The Honeywell eco line, for instance, are very energy efficient.
The Friedrich SS10L10* is the most energy efficient air conditioner with a rating of 12.
The most energy efficient radiator heater is the oil filled one. A better option would be an electrical one because those are almost 100% energy efficient.
Currently Friedrich offers the most choices in energy efficient air conditioning
The question is better defined as "What the most energy efficient portable heater?" Because one would assume that you will want to be able to take the heater with you when or if you move.
One of the most energy efficient water heating methods is the heat pump water heater. This method is proven to be two times more efficient over the standard electric water heater.
Ruud air conditioner and home depot offer energy efficient air conditioners to help lower your monthly bill.There are many companies that sell energy efficient air-conditiones but I reccommend these because they are very well known and have good service
form_title= Energy Efficient Air Conditioners form_header=Keep your cooling bill down with an energy efficient air conditioner! Will you be replacing a previously installed air conditioner ?* = () Yes () No () Not Sure How many air conditioners will need to be installed?* = {1,2,3,4,5,6,7,8,9,10, More than 10} What is your general summer climate?* = _
Valco Infrared heater can be used as a space heater. The can save you lots of money on energy costs.
An electric heater ( the only known 100% efficient device ).
One can use an energy efficient heater to save on gas and electric bills, one can also wear warm clothing like sweaters and socks to help minimise the need for heating.
Look for any with an energhy star lable but the Amana 12000 BTU Energy Star Room Air Conditioner with 11260-BTU Heater is good.