From custom duct work to custom design of your total enviroment the high-tech professionals at Overcashier & Horst can meet your needs. When was the last time you had a precision tune-up on your heating and air conditioning equipment? Preventative maintenance on your energy appliances is like money in the bank. Our service technicians are experts in maintaining and repairing gas, oil and electric furnaces, hot water heaters, boilers, heat pumps, air conditioners and more.