The furnace is working at this time, however, is extremely dirty clean blower motor and internal cabinet heat exchanger has flame and impingement and stress points informed the homeowner of the condition of the system. It is 20+ years old and definitely will need to be replaced soon as it is inefficient, and there are multiple parts that are going to need to be replaced soon. The 14 x 25 by one filter was fine David purchased the VIP home service plan and I did a complementary blower motor cleaning Need to return for the spring air conditioning cleaning in a couple months when it warms up