Unfourtinatly Holmes does not sell parts to fix their heaters, if the unit is still under warranty you might be able to get it fixed, the company that makes the thermstats does not sell to end user and they state that you must purchase from Holmes, You could always try calling holmes and see if they will sell you one, but dont get your hopes up for that it seems they just want to sell you a new heater, one other option is to check e-bay or other sites that part heaters out. if you are good with electronics you could get a generic thermostat that will control the unit. (might be your best option) And wire it in, just be sure you know what you are doing because we dont want any unsafe Situations a life is worth more that $75 for a new heater

You can buy this parts from:--
www.repairclinic.com

or directly at :--

http://www.repairclinic.com/Holmes-Parts?s=b148c221

the cost of part is 75 dollars.

This will help. Thanks please keep updated.please do rate the solution positively .thank you for using fixya

The cover should pop off so that you have access to the thermostat. You will have to go to the manufacturers website to find the parts and the last one I changed out was about $18.00

Hi, I found this model of heater for you. As far as the thermostat i didn't come up with anything on that part number. You can contact this link and find out if they can get one. The price of a new heater is $34.95 online if you cant find the control. Here is the link: www.Buy.com. Hope they can send you in the right direction.
Good Luck,
Shastalaker7