I spent yesterday afternoon at a home inspection at a property I have in contract. The home inspector tested the central heat and air conditioning system, and noted that there was not a significant change in temperature after letting the system run for 20 or so minutes. This was a matter of obvious concern to my client (the buyer), as repairing or replacing a central heat & air system is not inexpensive.
Today I met an HVAC contractor at the house, and he was able to diagnose the problem in about 30 seconds - the filter had not been replaced in a long while. Sure enough he popped the filter out, grabbed a new one off his truck, and tested the system. After running for a couple minutes, he measured a very significant change in temperature - problem solved for a $2 item and a service call. Glen with Elite Heating and Air (916-214-5297) suggests replacing the filter every other month.
Ok, that's just gross. Were the owners running a dirt farm in the living room? I have actually heard of this before. It also greatly extends the life of a furnace.
That is sad. We replace every month and service our systems every 6 months. Some people wonder why they can not breath in a home...