I keep my thermostat set at 64 degrees. When I woke up this morning,
the house was 59 degrees inside. I left for a little bit and came back
to see the house was now 58 degrees inside. I bumped the t-stat up to
70. About 15 minutes later, the furnace clicked on and got the house
up to 62 degrees before shutting off again. It is now 60 degrees in
the house and the furnace has not came back on. It has been about 30
minutes since it shut off. What could be the problem?

Thanks