Corrections/expanding Pipe insulation thread

David Nadle chimed in on the original thread and pointed out I had made an error in interpreting  how the chart was laid out, so I thought I would correct my numbers.  I also expanded them some for typical applications.

Using Brad's Data (corrected) for 2 inch pipe insulation

1inch wastes 60,231 btu/yr

1 1/2 inch wastes 37,793 btu/yr

2 inch wastes 26,727 btu/yr



Assuming $1.00 per therm gas cost ($1.00 per 100,000 btu's) and the cost per 3 foot length QCA posted, I came up with the following simple payback numbers for various conditions.

80% seasonal efficiency:  This would be for modular staged wetback steam boilers with on/off power burners or wetback steam boilers with modulating power burners with a system and boiler capacity closely matched to the actual heat loss (very rare condition).

Simple payback (materials only) for using 1 1/2 inch instead of 1 inch: 4.6 yrs

Simple payback (materials only) for using 2 inch instead of 1 inch: 6.5 yrs



70% seasonal efficiency:  This is more likely for the above boilers in a typical oversized steam system.

1 1/2 inch instead of 1 inch: 4 yrs

2 inch instead of 1 inch: 5.6 yrs



55% seasonal efficiency:  This is a likely  typical efficiency for typical 80% commercial cast iron sectional boiler with open tube type burners in a apartment complex with the boiler matched to the cast iron radiation.  A typical home boiler of this same design is probably slightly better, say 60%, when running cast iron because internal heat gains as a percentage of load are not as high as in an apartment complex and the boiler may have a stack damper to help reduce stand by losses.  This is a typical setup in most homes and many apartments in the Chicago area.

1 1/2 inch instead of 1 inch:3 years

2 inch instead of 1 inch:  4.4 years



For QCA, this last one is probably your condition.



This exercise really does confirm the International Energy Code recommendations.... even the 2 inch payback is under 7 years under the most optimum conditions.   For you folks out east that have even higher fuel costs, your payback is probably much better