Cost control/heat loss/thermostat location-related question

McKern_2

Here's the situation—1920 condo building (3 floors, 6 identical 1500 sq ft units, smaller garden unit; one pipe system), the thermostat is located in one of the first floor units. According to our gas bill, energy use for the building increased 12.5% (in therms of thems/heating degree day) for 2007 compared to 2006. We have a service call scheduled to deal with this and other issues, including the fact that it's been at least 3 years since the last "annual" inspection.

Conventional wisdom attributes the increase in energy use to leakage from missing storm windows in the unit where the thermostat is located. Our service company has suggested that we consider relocating the thermostat or replacing it with a device that monitors the temp in several locations. (Per advice received here, I've also asked for info about Heat-Timer devices.)

While preparing for this upcoming service call, I discovered that the temp in all four of the 1st and 2nd floor units generally corresponds to the thermostat settings, i.e., the much better insulated units don't overheat before the thermostat in the drafty unit is satisfied. Given this, it seems that our assumptions regarding the relationship between missing storms windows and the increase in the fuel use are off the mark.

Does this mean we should rule out moving the thermostat or switching to the device the monitors the temp in several locations--at least for the purpose of cost control?

Could it be that our system cranks out enough heat to overcome the heat loss, therefore, the “leaky” unit reaches the thermostat setting in about the same amount of time as the better insulated units?

Based on past experience, I can’t count on the guys who service our system to know what they’re talking about. I had hoped to replace them with a steam-oriented company, but the two that came with excellent recommendations are closed to new clients for the remainder of this year. In the meantime, we’ll have to get by with my copy of "The Lost Art of Steam Heating" and The Wall.

Thanks for any advice.

BTW--The most vocal proponent of the missing storms=longer heating cycle=higher fuel bills theory also thinks that the 3rd floor runs cold because the boiler shuts down too soon to fully heat those units. In an effort to address this, I just learned that last year he installed Vari-vents on the radiators nearest the thermostat, adjusted to slow the venting so that the boiler would run longer to satisfy the thermostat. Go figure.