text: 
  var Thermostat = function() {
    this.ABSOLUTE_MAXIMUM_TEMP = 33;
    this.POWER_MAXIMUM_TEMP = 26;
    this.DEFAULT_TEMP = 20;
    this.MINIMUM_TEMPERATURE = 10;
    this.degrees = 20;
    this.powerSaving = true;
  };
  
  Thermostat.prototype.maxTemp = function() {
    if (this.powerSaving) {
      return this.POWER_MAXIMUM_TEMP;
    } else {
      return this.ABSOLUTE_MAXIMUM_TEMP;
    }
  };
  
  Thermostat.prototype.increase = function(value) {
    if (this.degrees + value < this.maxTemp()){
      this.degrees += value;
    }
  };
  
  Thermostat.prototype.decrease = function(value) {
    if ((this.degrees - value) < this.MINIMUM_TEMPERATURE) {
      throw new Error("Temperature cannot be decreased any further.");
    } else {
      this.degrees -= value;
    }
  };
  
  Thermostat.prototype.reset = function(){
    this.degrees = this.DEFAULT_TEMP;
  };
  
  Thermostat.prototype.powerSavingOff = function() {
    this.powerSaving = false
  };
  
  Thermostat.prototype.powerSavingOn = function() {
    this.powerSaving = true
  };
  
  Thermostat.prototype.energyUsage = function() {
    if (this.degrees < 18) {
      return 'low-usage';
    } else if (this.degrees < 25 && this.degrees >= 18) {
      return 'medium-usage';
    } else {
      return 'high-usage';
    }
  };
  