inside/outside temperature difference
If the outside temperature goes below 18,i set the thermostat to 73 degrees,room temp may get to 69 after many,many hours. Leaving it at 73 thru the night,in the morning it will be around 68. We used to have oil heat,converted to gas. Never had this issue with oil. Numerous service calls,energy audit with improvements have not resolved the issue. Brr !!
Re: inside/outside temperature difference
Could you tell us what type of heat you have---forced hot air, forced hot water, radiant, etc???
Do you have high ceilings, drafty windows or limited insulation inside the walls??
What are the service people telling you when they have come over???
Do you have what's known as outdoor reset, that tells the furnace/boiler to quit making heat at a certain temp & have you tried to raise the T-stat higher, say to 80 degrees temporarily to see if that will provide more heat to the interior without the furnace/boiler quitting at a certain temp??
There is a high-limit switch on both forced hot water & forced hot air that limits the the temp of the HW or HA that is being delivered to the living quarters----you'll have to talk to the service people & get them back at least one more time---it is an easy matter for the tech to adjust the high limit switch on the boiler/furnace so that more heat is provided.
If calling the same service person doesn't work, call some other service tech until you get results.