Upon arrival customer stated that main floor heating system was having intermittent issues, stated he changed thermostat batteries and issues still continued where thermostat would go blank and reset to 62 degrees. After inspection of 5 year old furnace found that thermostat is starting to go bad, the lo batter displayed on screen and then would turn off and reset. Changed out batteries and thermostat did not continue to have this issue but advised customer older thermostat is failing. Checked over all operations of system, blower wheel is dirty, inside system is clean, made sure pressure switch tube port was clean and flame sensor was clean. Amps on inducer draft motor test good, amps on blower motor tested good. Did not find any issues with heating performance. Recommended standard thermostat or WiFi thermostat, blower wheel cleaning, Uv light, and emergency wet switch, customer declined recommendations at this time advised me to send all estimates via email. System is heating at thi