For those of you who are conducting residential energy assessments; are you recommending "on demand"  hot water re-circ. systems?  I'm finding that many of my customers waste a ton of water while they wait for the hot water to arrive. This is the case even with an insulated pipe because the water is simply wasted down the drain where as a properly configured re-circ system will return the water in the pipes to the water heater.  I recently became aware of a re-circ. system called Switch2o at www.switch2o.com that is enabled when the light switch in the room is thrown. It claims to waste only a cup of water and produces water saving far in excess of dual flush toilets. Thoughts?

Views: 629

Reply to This

Replies to This Discussion

The issue is water is cheap in most parts of the country, a recirculating water system doesn't justify the payback time.

No offense Bob but this is the kind of thinking that has largely been responsible for the depletion of our natural resources.  Wouldn't you agree?

Definitely true.

Agreed. The big issue is natural resource prices have been subsidized by the government for years. Maybe not the water itself, but the electric and gas to heat the water have... At $3 per 1,000 gallons of water payback time on a $500 (installed) recirculation system is VERY long. There is a lot of "lower hanging fruit" in most homes that offers quicker payback times.

Navien has a fantastic condensing 98% efficient unit with a buffer tank AND pump, with internal recirc that can be programmed for when most likely needed AND can be connected to an external recirc loop.  That's the setup I'd recommend.  

I'm going to come to Bob's defense on this.  A recirc is for comfort and convenience.  The water saved is give up multi-fold in energy consumption. 

Is it worth $3-500, and additional BTU loss through a recirc, to save 1000 gallons a year?  

Is your house so good that that $300 couldn't save MORE resources if spent elsewhere?  

Hot water recirc is fairly common here. For some folks, it's a conservation issue because they have wells that don't produce much, so water down the drain is a problem. For others, it's a (usually) energy-wasting convenience that has the effect of conserving water, when what they really want is no wait time.

I'd say the majority of the systems I see are wasteful... over-sized pumps that run continuously, over-sized water heaters pushing water through over-sized, uninsulated lines that are too long. A small percentage are smart... a timer on the pump so that it only operates before/during breakfast and during/after dinner for short periods, an aquastat that turns the pump off if the water in the line is hot enough, short runs of well-insulated piping, etc. 

My brilliant top-secret invention is a faucet that doesn't start flowing water the second you move the handle--it recircs the water until hot water arrives, then it starts flowing. No wasted water, no recirc unless you're about to use water. All you have to do is get used to waiting a few seconds before using the water... which you're probabIy doing anyway. I should be a millionaire soon.

Make it look pretty and I'm sure you will sell some !!

That sounds pretty cool. 

There are plenty of "on-demand" systems out there that are fully integrated already - all you need to do is simply push a button & they stop as soon as hot water is detected - no need to buy a cobbled together "deluxe" system to get that. As for the savings, that depends a lot on the families usage, but most people don't require hot water when they turn on the bathroom light.

As for dependent savings your calculations are based on usage instead of operational costs.  It's all relative.

Switch2o has the cheapest operational cost of the on demand systems and probably similar to the button type. With the button, though you'll need a button at each station.  Also, I know you mean well but this is anything but a cobbled together system.  Perhaps you don't understand the configuration?

Ah ha - you know there is a big difference between "became aware" and I sell or offer... In case of "I now offer" you would have either gotten a private reply, a different worded reply, or none at all.

No it is not relative as it is dependent on a HO's needs, usage & their plumbing configuration. As for the cheapest operational costs - I highly doubt it, unless you have looked into every system out there & run the numbers. I dare say a vacuum switch that doesn't require electricity to start the pump is the most efficient. For the basic- for the thermostat shutoff, maybe but I doubt it - as for the pump, I highly doubt that the pump is the most efficient & cheapest to run unit out there.

A friend of mine set his up using a motion sensor in the bathroom... the pump starts anytime you set a foot inside the room. 

RSS

Featured Forum Discussions

BPI Anaylist and installers

Started by Larry R Waters in BPI. Last reply by Quinn Korzeniecki 16 hours ago. 1 Reply

What causes a temperature plane in a home

Started by Energy Wise Solutions in HVAC. Last reply by Brad Cook yesterday. 6 Replies

Velocity Pressure Testing

Started by Horace Douglas Hunt, Jr. in General Forum. Last reply by Horace Douglas Hunt, Jr. Apr 15. 2 Replies

Videos

  • Add Videos
  • View All

Latest Activity

Chris Woods added a discussion to the group Energy Auditing Equipment for Sale, Trade or to Purchase
Thumbnail

Minneapolis Blower Door Fan and Door frame $990 OBO

I have a used Minneapolis blower door fan (fan only, no controls or panel) and the blower door…See More
6 hours ago
Profile IconManuela L Heyn and Paul Nagel joined Home Energy Pros
9 hours ago
Bill Spohn replied to Eric Sperline's discussion Wanted: Energy Auditing Equipment for sale in the group Energy Auditing Equipment for Sale, Trade or to Purchase
"If you choose to buy new, give TruTech at call at 1-888-224-3437 option 1"
12 hours ago
Home Energy Magazine's blog post was featured

The Legends of Home Performance

A project long in the making, we're happy to finally reveal some of our Legends of Home Performance…See More
13 hours ago
Quinn Korzeniecki replied to Larry R Waters's discussion BPI Anaylist
"Hi Larry, We're glad you're reaching out to hire some BPI folks! You can also submit…"
16 hours ago
Larry R Waters posted a discussion

BPI Anaylist

Industry leader in the north bay area California. Looking for experienced professionals and future…See More
23 hours ago
Larry R Waters joined Diane Chojnowski's group
Thumbnail

Job Board

This group is for posting jobs related to all aspects of the home performance industry including…See More
23 hours ago
John Nicholas replied to Jim Fowler's discussion TREAT modeling of mid-rise apartments low heating load
"So why is tenant behavior significantly different in this building?"
yesterday

Home Energy Pros

Welcome to Home Energy Pros – the unique digital community by and for those who work in the home energy performance arena.

Home Energy Pros was founded by the developers of Home Energy Saver Pro (supported by the U.S. Department of Energy) and brought to you in partnership with Home Energy magazine.  Home Energy Pros is sponsored by the Better Buildings Residential Network. Please honor our Guidelines

© 2017   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service