Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: Don't have a manual for this heater.  Can someone tell me how to set the "ECO" mode, PLEASE!
Document: Can't really tell how much this unit is contributing versus our house heater which runs on a thermostat and we felt the infrared heater would heat enough to kick off the thermostat thus saving us gas on the house heater. The trouble is how can we tell until we have more drastic weather and see if the additional heater is saving us money.
I selected this heater because of all the positive reviews. It does heat up the room, it's very subtle, & I didn't realize the room was getting warmer. Then....when it reaches the set temp.,it blows cold air to cool off the element inside.So....after warming you up, it vigorously cools you back down! Something I didn't appreciate!
I work from 8pm to 4 am. I leave the thermostat on my home heating system set low. I place the Lifesmart heater in my bedroom and program it to turn on an hour before I get home from work, so I have a nice warm bedroom without having to heat the whole house.
Used this little heater to keep my office and bedroom warm this winter when propane hit $5 a gallon. Don't expect miracles out of this thing, but it was enough to keep my 10x15 room 68 degrees on bitter cold winter nights in a poorly insulated 2nd story. great to set by your desk and keep you warm in the winter, instant heat.
I have had our Stealth 6 Lifesmart heater now for over two years. It works quite well. We are using it as the primary source of heat in a large bedroom 530 s/f with vaulted ceiling. We have a ceiling fan to distribute the heat. With the outside temperature today at 2 degrees the bedroom is at 68. The heater is set for 72. Yes the heater runs non-stop on cold days like today.
works Great !!!!!! !working hard in record cold winter,would tell others fighting ridiculous propane prices ( how convenient for profits in a freezing winter)
Noticed the heater cycling off/on when in the economy mode, so at least I know it's working. Great supplemental heat source for our winter cottage in Northern Michigan; saves on propane costs. We haven't seen the electric bill yet as we've only had the unit about 3 weeks......
It also has an auto on/auto off timer. I have not used that either, but figure the auto on will work nice to come on a couple of hours before you get home. It's not like an alarm clock. You have to tell it to come on in a certain amount of hours. Other complaints included that the display shows the setpoint, not the actual temperature. OK, some people will want it one way, some the other.
I am in mountains and use Propane to heat. These units (I have three) serve as a great way to supplement the propane and keep the house comfortable. They use a minor amount of electricity and can be set to time off so at night they shut down after we are toasty in bed.
have a lower level familyroom and it is 20 x 13 and this thing running around the clock would not heat it up past 66, had termostat set on 75 for 2 days straight....took it back. might be good for a bedroom, but a bigger room, forget it.
Answer: Send her a manual. It should also have info on replacement parts and warranty as well.