The heating element in the Mytee Lite is an in-line heater, meaning that as the water runs from the reservoir and through the heater on its way to the spray head it is heated up. Therefore, you will notice that the water is boiling hot when you first spray it out, as that water has been sitting in the heating element for 15 minutes or so. However, if you are constantly spraying, the water does not have enough time in the heating element to heat up, therefore it will come out lukewarm. If you spray, extract, spray, extract,... the water should have enough time to heat up though. Whenever I use cold water in my extractor I heat it up beforehand using a bucket heater which you can purchase for under $40, just put it in the reservoir and the water is hot before it enters the in-line heating element and comes out even hotter. You can buy a bucket heater at any tool store like Northern or Tractor Supply. Hope this helps.