High Utility Bills

We recently got a call from a homeowner in Prospect, KY who built a very nice custom home and made extra efforts to make it efficient and comfortable, yet was still experiencing high gas bills and uncomfortable areas in the house. 

We decided to use an infrared camera and a blower door test to try and locate the source or sources of the home owner's problems.  We also tested the duct leakage in the house using a Minneapolis Duct Blaster.

The house had three separate furnaces and ductwork systems, and the furnace that supplied air to the main floor was on a "zoned" duct system. 

This main furnace was a 94 Kbtu, 90% efficient unit, but because it was connected to a zoned duct system that was not sized large enough to handle the air movement from the furnace, the 90% efficient furnace performed more like a 70% one, or worse.

Even though the house was insulated and air-sealed with foam insulation, the IR camera and blower-door test revealed several areas where cold, outside air was entering around windows and wall-ceiling connections.

To the credit of the insulation installer, the problems were not entirely their fault.  During the inspection in the attic we found that the spray-foam that had been installed had been torn away and damaged by other subcontractors after their work was complete.

The holes you see were allowing a lot of cold unconditioned air to enter into the living areas, creating cold walls, ceilings, and drafty areas inside the attic area above the kitchen.  See the IR pictures below for examples of those areas affected.

Further inspection in the house also revealed excessive heat loss from hot water lines behind interior walls because of an automatic hot water cycler on the gas-fired water heater. 

While these automatic systems are very convenient and provide instant hot water during pre-scheduled times of the day (morning time most often), they also unnecessarily circulate hot water throughout the entire plumbing system and use excessive natural gas in doing so. 

Check out the pictures below to see how much heat was radiated into the walls from this system.

After the entire Home Performance Inspection was complete, we concluded that while there were areas of air leakage and missing insulation, the main cause of the high utility bills was the three oversized furnace systems, and mainly the duct zoning system on the large furnace that provided the majority of conditioned air for the house. 

The zoned system was not designed properly with respect to the size of the ductwork and the furnace output, and thus was "choking" the furnace, restricting airflow to certain parts of the house and decreasing the efficiency of the furnace itself.  The automatic hot water cycler also contributed to the higher natural gas bills.