When I arrived, the home was 67° when the thermostat was set for 71. I went through the settings on the thermostat to make sure there was nothing weird set on the thermostat causing it not to keep the temperature in the home and range. Thermostat was set up properly. I went down to the furnace since the customer said that the issue only happens during furnace season. The furnace was in a one hour lockout due to loss of flame. I cleaned flame sensor and spark igniter. I checked pressure switch and tubing. I checked the cleanliness of the burners. Gas pressure on the Gas valve was low. This could have caused the loss of flame along with the carbon buildup on the flame sensor and spark igniter. I recommended a less restrictive air filter to help the system breathe better and not overheat. Furnace is running within manufacturer specifications at departure.