Location: Medfield, MA
This house is a good example of how combustion efficiency does not directly relate to actual comfort and savings. Since the system we installed is now weather responsive, it is a lot more comfortable because the radiators and large piping is almost always warm – thus cutting down on the large temperature swings, the house used to experience. If using combustion efficiency alone, the house should have had a 15% drop in oil combustion. The same control that keeps the house more comfortable also enhances system efficiency. Two years worth of tracking show a fuel usage drop of 35%! This helps to show how AFUE efficiency numbers can be very inaccurate.
Before (Photo #1):
- 13 year old oil-fired boiler in turn of the century New England estate home with large cast iron radiators.
- Combustion Efficiency: 73%
After (Photo #2):
- Viessmann Vitola 200 VB2-63
- Viessmann weather responsive Vitronic 100 KW-10 control
- Combustion Efficiency: 87.5%