The firing rate of the new system and the old system are identical, meaning both heating appliances have the same input (800,000 BTUh). They both consume $17.52 per hour, but the new system only gives up 10 per cent efficiency, meaning only $1.75 is wasted per hour.
The additional bonus is, on this project and many others, the company has found runtime hours to fall by 33 per cent. This is because the new unit is adding heat to the pool at a higher rate than the old unit. The new equation is as follows:
1,500 (original runtime hours) x 0.33 (percent reduction in runtime hours) = 495
1,500 (original runtime hours) – 495 (reduction in runtime hours) = 1,005
$17.52 (per hour) x 1005 (annual runtime hours) = $17,607
To find the potential fuel savings, subtract the new heating cost from the old heating cost:
$26,280 (pre-retrofit annual fuel cost) – $17,607 = $8,673 saved per year.
The reduced runtime—thanks to more BTUs making it into the water and less heading up the chimney—provides the bulk of the savings. The body of water still needs the same BTUs, it is only getting it quicker post-retrofit. The reduced runtime also means less carbon emissions and less wear on equipment. Depending on the application, other control strategies to reduce input (total installed capacity) can be used by staging multiple, smaller units; however, this is another topic on its own.
Savings add up
While $8,673 is nothing to scoff at, it is to be noted some companies service many homeowner associations (HOAs), which have half a dozen or more outdoor pools of this size, and these clients would stand to save more than $50,000 each year. The energy consumption and savings potential are relative to the size of the pool facility.
One can also imagine how cost savings would rise if the cost of LP, or in many cases natural gas, rose. Finally, this author would not be surprised if high efficiency equipment becomes code-mandated for pool heating applications in the not-so-distant future.
Author
Tom Soukup is the principal of Patriot Water Works Co., with more than 20 years of experience as a hydronic designer and installer. He specializes in high-efficiency and green technology and brings his expertise to custom hydronic work, pool heating, and agricultural projects. He can be reached at twsoukup@patriotpaterworks.com.
