November/December 2005
A version of this article appears in the November/December 2005 issue of Home Energy Magazine.
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November 01, 2005
Peak Question I have a question regarding your article about inline or instant gas-fired water heaters (“Tankless Option Improving,” July/Aug ’05, p.18). Inline or instant gas-fired water heaters have a gas input of 135,000–195,000 Btu per hour, versus the standard storage water heaters, which have gas inputs of 35,000–40,000 Btu per hour. Since the instant water heaters are more efficient and have other attributes that make them attractive as replacements for storage water heaters, would greater numbers of the more efficient water heaters in a utility’s service area have an effect on the peak demand for natural gas? Phil Smith Energy Information Center Minnesota Department of Commerce St. Paul, Minnesota Author Dave Springer replies: We have heard anecdotal concerns raised that high-capacity tankless gas water heaters may present a peak-load problem for some gas utilities.  As you point out, peak gas demand may be 4–5 times higher than for a standard storage gas water heater.  During winter months, when the cold winter inlet temperatures entering the tankless heater are at a minimum, morning showers are likely to be coincident with the peak space-heating load.  We do not have any solid data on ...

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