Im not sure my central heating is working fine. I bought a new home and I have lived there about 2 yrs but I rarely used my central heating (long enough) over this time. Recently I used my central heating long enough (over 3 hrs) and noted that while the heating is good initially, the air looses the heat and eventually eventually I feel the house is not warm enough. The thermostat works well (a new digital one was fitted a few weeks ago as I thought this was the problem). The mechanic said there was no problem with my central heating but I'm concerned that the heating is not sustained over the time it is turned on. Could there be a problem and if so, what could this be?

I need more details to help. What sort of a system is it, gas, heat pump, etc. Is it more than one heating stage? You might also try putting a thermometer in the vent and seeing if it actually is putting out cooler air later in the cycle.

Your problem could be as simple as heat loss through window, doors or poor thermostat settings!You might have to evaluate where you are losing the heat and insulate as needed!Windows are notorious for heat loss as well as attics!:cool:

How exactly do you check for heat loss? I don't see cracks in the walls or along windows or around doors, so probably I'm not the best person to check! Are there professionals who do this? If so, what is their trade (what are they called, I mean the way you say "plumber" for plumbing issues) I have an electric heat pump; the outside unit was replaced about 2.5 yrs ago. The house is about 15 yrs old and in fairly good shape (in my view) thanks

Your heat pump could be low in Freon, and the coils outside frosting up after running for a while. You might even be able to see that looking in the outside unit. Could be a more complicated thing like an expansion valve failing. You may want to be sure there really is a problem before calling a tech. One more thing, go outside as soon the unit starts and try to remember how it sounds. Then go back out after you think you are getting less heat and see if it sounds any different. You are not talking the minute or to the blower runs after the heat cuts off are you?

Heat pumps never will produce as warm of air coming out the vents as gas or oil. They can still keep a house comfortable where it doesn't get that cold.

If you want the house inspected, perhaps the electric company can suggest somebody or might even do it for free. In many states they are under pressure from the regulators to help conserve energy. Putting money into insulation or better windows rather than new electric plants can be a win win for all.

Thanks all, this is very helpful. I will listen to the sound, I will check the frosting, and ooh no, the cold air starts after several hrs running but I have not noted precisely when. I know one night I slept warm and woke up a bit cold with the heating running and wondered why. Also, the (new) thermostat does not seem to get off often enough when the heat is reached - as per thermostat reading (and indeed the house feels warm) but it stops running briefly and then starts running again. I also have home owners insurance covering this. I just don't like being in an atmosphere that is not warm ( I normally keep the heat at 71 degrees and that works for me fine)

Sorry I should have been more specific!Your utility company can inspect your home for free and tell you if your losing heat and how much .I'd like to know what part of the country your from?:cool:

Maryland - it should not be that cold, right! Thanks again and I will get the utility company to come have a look... very useful info thank you. I use PEPCO.

Also with a Heat Pump your coil in the airhandler must be clean. If not the compressor outside could be overheating