residential boiler charts and graphs

The duplex I live in is heated by a hot water boiler system. It's the first place I've lived since childhood with a boiler, and I was excited about it. For the uninitiated, boiler/radiator heating is very different than forced-air heat from a furnace and duct system. Air has very little thermal mass, so it heats up and cools down quickly. It also rises to the ceiling, so your head is too warm, while your feet are perpetually chilly. Radiators are made from heavy cast iron, and have a LOT of thermal mass. They take a long time to warm up, but they retain a lot of heat energy for a very long time. The biggest benefit is that the warmth from radiators is transmitted by means of radiation as well as convection into the air. Radiant heat is the same heat you can feel when the sun shines on you or you are standing near a campfire. Radiation travels in all directions through space until it is blocked by something. This means that as long as the radiator is "shining" on your body, you will be receiving warmth. Try that with forced-air, which has only become so popular because it allows for central air conditioning. But enough with theory, let's look at the equipment and then the experiment...