[Greenbuilding] Ask Pablo: Will a "Water-Saving" Hot Water Recirculation Pump Really Save Me Money?

[natural building]

Pablo's calculations do not seem to include any insulation on the hot-water supply lines, nor do they account for recirc pumps that have timers and aquastats which are available in any reasonable $200 model (Grundfos for instance). Set up properly, this means that the pump is not circulating water during the night or at low-use times of the day which would dramatically reduce heat-loss. He also implies that the pipes are located in un-conditioned space at an average of 52 degrees F. I would suggest this is unrealistic.

That being said, his underlying argument that they use more energy than they save in water is probably true. But not nearly as extreme as he makes out IMHO.

Regards,
Steve Satow

www.naturalbuildingsite.net
naturalbuilding at shaw.ca

On 2011-05-17, at 5:45 AM, Steven Tjiang wrote:

> Recirc pumps saves water but are an energy waste if run continuously.  Ours has a button that you press manually 30 seconds or so before you use your faucet, and goes off when the hot water reaches the faucet.  Still I doubt the energy savings will offset the installation cost in any realistic amount of time.
> 
> ---- Steve (KZ6LSD)
> 
> 
> On Tue, May 17, 2011 at 5:41 AM, Stephen Collette <stephen at yourhealthyhouse.ca> wrote:
> Here is a link (hopefully it's not scrubbed) on hot water recirculating pumps. Seems according to Pablo, they do not add up. I have one and unplugged mine as I thought (not verified, but eyeballing my electricity bill and guesstimating) that it was costing too much to run. I would be curious about thoughts on this idea from others, as I know we have had discussions in the past on these units.
> 
> http://www.treehugger.com/files/2011/05/ask-pablo-hot-water-recirculation-pump.php
> 
> If the link is scrubbed, please go to treehugger . com and search ask pablo - hot water recirculating pumps, and you should find it hopefully. or drop this on the end of it. /files/2011/05/ask-pablo-hot-water-recirculation-pump.php
> 
> Cheers
> 
> Stephen
> 
> Stephen Collette BBEC, LEED AP, BSSO
> Your Healthy House - Indoor Environmental Testing & Building Consulting
> http://www.yourhealthyhouse.ca
> stephen at yourhealthyhouse.ca
> 705.652.5159
> 
> 
> 
> 
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> 
> 
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