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Using STCs to Understand Heat-Pump Hot-Water System Performance

by Richard Keech

2019-07-20

STCs are the basis for federal clean energy rebates, including for heat-pump hot water systems (HPHWSs) and solar-thermal hot-water systems.  However, they can also be informative in understanding the performance of HPHWSs.

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Performance of heat-pump systems is indicated by number of STCs earned

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Hot water – more than meets the eye

by Richard Keech
orginally published December 2016, re-blogged 2019-07-20
A couple of times recently on this list, the question of the relative merits of solar hot water vs heat pump hot water has arisen. There’s an oft-overlooked factor to consider when comparing these and that is the temperature set point, and more broadly how the temperature is regulated. Temperature regulation of heated water systems is a matter which has serious impact on energy consumption, as well as on biological safety (due to legionella) and on burn safety (due to the risk of scalding).

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Will covering IC-rated lights make them fail quickly?

by Richard Keech

2019-04-27

I’ve heard a few people say that covering IC-rated LED lights is bound to cause accelerated failure rate.  One the one hand it’s well known that electronic devices fail more quickly when they get too hot.  On the other hand, you’d think that the manufacturers of IC-rated lights would not rate them as OK to cover if it would cause significant reduction in their likely service life.  So I thought I’d delve a little closer.

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