First of all, it is important for you to know that (according to a consumers' guide to heater selection that is printed on the packaging boxes of some heaters) heaters with heating elements that ILLUMINATE (radiant heaters) tend to produce the STRONGEST, most INTENSE heat (as compared to CERAMIC, OIL-FILLED ELECTRIC RADIATOR and HEATER/FAN heaters). Radiant heaters have heating elements that heat up to temperatures as high as 1,000 degrees Fahrenheit (unlike CERAMIC, OIL-FILLED ELECTRIC RADIATOR and HEATER/FAN heaters). Radiant heaters tend to be made of TWO types of illuminating heating elements: they are made with either (1) quartz tubes, or (2) exposed wire elements. Radiant heaters that are made with quartz tubes are MORE ENERGY EFFICIENT than radiant heaters that are made with exposed wire elements. The quartz tubes actually have wire elements inside of them. The quartz tubes provide insulation for the wire elements, which allows the wire elements inside of them to heat up intensely WITHOUT USING AS MUCH ELECTRICITY (unlike radiant heaters with EXPOSED wire elements that are NOT enclosed inside of quartz tubes). I currently own THREE different radiant heaters. They are all made with quartz tubes. I currently own: (1) The Homebasix LH890S Vertical Quartz Heater, (2) The Holmes HQH307-NU Quartz Tower Heater, and (3) The Sunbeam SQH310 Quartz Tower Heater. All three heaters have FANS, but the Homebasix LH890S Vertical Quartz Heater is the ONLY one that is "fan-forced" (just because a heater has a fan does not mean that the heater is "fan-forced"). All three heaters have the ability to raise the room temperature, but the Homebasix LH890S Vertical Quartz Heater raises the room temperature MORE QUICKLY than BOTH the Holmes HQH307-NU Quartz Tower Heater and the Sunbeam SQH310 Quartz Tower Heater... despite the fact that they are ALL 1500 watts and 5,120 BTU'S. For whatever reason... the Homebasix LH890S Vertical Quartz Heater is the one that (according to tests that I have conducted over the last year with the use of an ANALOG THERMOMETER) raises the room temperature the FASTEST... generating the GREATEST increase in room temperature in a given time period. I have used these three heaters (one at a time) to raise the temperature of my ENTIRE APARTMENT, rather than just one individual ROOM. I live in a medium-sized WELL INSULATED studio apartment (no sources of air leaks or drafts in the apartment). The apartment consists of a medium-sized kitchen, a medium-sized sleeping room, a small bathroom, and a small main entrance area (where the front entrance door is). The entrance area separates the kitchen from the sleeping room... with the bathroom right in front of the entrance area. Over the last year (during the winter season), I have used my three heaters (one at a time) to raise the temperature of my entire apartment WITHOUT the use of my CENTRAL heating system. I set the heaters in the entrance area, where they are able to circulate heat EVENLY throughout the apartment. Both the Holmes HQH307-NU Quartz Tower Heater and the Sunbeam SQH310 Quartz Tower Heater are able to raise the temperature of the entire apartment by about 0.5 degrees Fahrenheit per hour (with OUTSIDE temperatures of 32 to 35 degrees Fahrenheit). But the Homebasix LH890S Vertical Quartz Heater is able to raise the temperature of the apartment by about 1.34 degrees Fahrenheit per hour (with OUTSIDE temperatures of 32 to 35 degrees Fahrenheit). On one morning, I ran my Homebasix LH890S Vertical Quartz Heater for three hours when outside temperatures ranged from 33 to 35 degrees Fahrenheit. During those three hours, that heater raised my apartment's temperature from 69 degrees Fahrenheit to a more comfortable 73 degrees Fahrenheit. That is a 4-degree temperature increase in just three hours... for an ENTIRE APARTMENT! Neither the Holmes HQH307-NU Quartz Tower Heater nor the Sunbeam SQH310 Quartz Tower Heater were able to raise the temperature to THAT degree in a three hour period (with the SAME outdoor temperatures). Perhaps the "fan-forced" feature of the Homebasix LH890S Vertical Quartz Heater is what gives it the ability to raise the room temperature more quickly than the others? Whatever the reason, the Homebasix LH890S Vertical Quartz Heater has proven to be the MOST EFFECTIVE 1500-watt radiant heater that I have EVER used! Here is an UPDATE to this review: On Friday, November 21, 2014, I ran my Homebasix LH890S Vertical Quartz Heater from 4:19 a.m. until 12:14 p.m. (7 hours and 55 minutes). At the BEGINNING of that 7 hour and 55 minute period, the OUTSIDE temperature was only 9 degrees Fahrenheit. At the END of that 7 hour and 55 minute period, the OUTSIDE temperature had climbed to 25 degrees Fahrenheit. WITHOUT the use of my CENTRAL heating system, my Homebasix LH890S Vertical Quartz Heater raised the temperature in my ENTIRE APARTMENT from a VERY CHILLY 64.2 degrees Fahrenheit (4:19 a.m.) to a MORE COMFORTABLE 71.2 degrees Fahrenheit (12:14 p.m.). That is a 7-degree temperature increase in just 7 hours and 55 minutes! That proves that the Homebasix LH890S Vertical Quartz Heater has the POWER to work EFFECTIVELY through HARSHER outside temperatures (temperatures WELL BELOW the 32-degree freezing point). So when it comes to 1500 watt electric heaters, the Homebasix LH890S Vertical Quartz Heater seems to be the SHORTEST DISTANCE between CHILLY and COMFORTABLE! Here is some advice (that is currently working for me) on how to give your apartment or home the ability to achieve warmth FASTER, and the ability to RETAIN the heat LONGER (if you have the type of window blinds that open and close UPWARD and DOWNWARD): make sure that ALL windows are COMPLETELY closed and LOCKED. Keep your window blinds CLOSED while heating your apartment or home, and close them by turning the rod in the COUNTER-clockwise direction (rather than CLOCKWISE). Be sure to let the blinds ALL THE WAY DOWN to the BOTTOM of the window, then push the bottom of the blinds AS CLOSE TO THE WINDOW AS POSSIBLE. Also, COMPLETELY close ALL of the CLOSET and CABINET doors in your house or apartment, including your SHOWER door (if you have one). It is best to CLEAN your Homebasix LH890S Vertical Quartz Heater once a WEEK so that it will CONTINUE to operate EFFECTIVELY. Because this heater is fan-forced, it tends to attract lint, hair and other debris frequently. Turn the heater OFF, then remove the two screws that hold the front grill in place, swing the front grill open, and carefully wipe the bottom, sides, middle and top of the metal reflector using a damp cloth. Be careful not to make PHYSICAL CONTACT with the heating elements while cleaning. Then wipe the lint, hair and other possible debris from the AIR INTAKE area of the heater. The air intake area is located at the FRONT of the heater at the BOTTOM. Then swing the front grill closed and screw the two screws back in place. Then wipe the TOP, SIDES and BACK of the heater... and you're DONE (the whole thing takes me only about 15 minutes).