Typical water usage?

[jayman]

Originally Posted by Shawn Clark

The sprinkler uses sounds about right, perhaps on the low side of what I expected based on your current in-home config/usage.

Proves how wasteful a lawn really is. If really dry, I'll use one of those drip hose things *maybe* once a week. Give one spot 10 mins or so, move it to the next spot

Originally Posted by Shawn Clark

for example you were each using 30 mins of hot water per day for showering, then one would expect fairly substantial water heating energy consumption.

I probably don't use 30 mins per day, and I shower at least twice a day. Even with that, I'm still squeaky clean

[jayman]

[quote=Shawn Clark;905485]

Originally Posted by Shawn Clark

I've not considered recirc systems as I would expect them to be energy inefficient. Circulating hot fluid in an external loop will produce greater ambient losses than if the line just cooled. There is also the cost of the pump/piping and energy used for pumping.

The only thing you gain with such a system is the convenience. Eg when you turn on a hot water tap, instant hot water. So you don't have to run water until hot water flows out

Correct the extra cost of running such a system far outweighs the extra water use of waiting for hot water

If a house is designed properly, there won't be long, long water lines. For example, a multi-floor house will have bathrooms and the like, clustered around a plumbing "stack."

Say the bathroom for that floor, and an ensuite, are back-to-back. The plumbing is then highly central to the stack, very short lines and minimal wasted water, hot water, etc. Ditto placing a bathroom for a particular floor back-to-back with a laundry room

[Shawn Clark]

Update: with 3/4 our showers now employing low flow showerheads (~1.5 gpm range) we are hitting about 4.2 ccf or 3,140 gal/month. That's about 26 gal/day per person. I might convert the remaining shower shortly. Still haven't done any of the toilets yet, though I've got a Toto HET on order.

I wonder if Ron succeeded in identifying/mitigating his water use problem?

[Shawn Clark]

Originally Posted by jayman

The only thing you gain with such a system is the convenience. Eg when you turn on a hot water tap, instant hot water. So you don't have to run water until hot water flows out

Although that is what I was thinking at the time, I see now that there are actually some minor savings to be had IF one uses on-demand recirculation (not continuous or thermostatic controlled.) The reason is that if it is done on-demand and circulates the cooled hot water back into the cold water line or back into the tank, fresh water addition is minimized. Also in winter less cold water is drawn into the home so the heat rise for the first gallon or two is reduced (e.g. if you have 45 F water inlet temp. vs. 68 F in the stagnant home plumbing.)

Of course, the way I laid it out above is not instant hot water. One would instead be doing a closed loop warm up and some finite warm up time (probably shorter with the pump.)

The devil is definitely in the details on this one. It might make sense for some extreme water restrictions or to cut some of the piping loss effects in winter. I've not tried to even estimate any potential savings scenario yet but there are two runs in my house that might be worth investigating: master bath shower and a long run to the kitchen faucet/dishwasher.

[jayman]

I learned from the homes I have built over the years. I now have all the plumbing arranged in a central "stack" so there is never 20ft between the hot water tank and the furthest tap

[hyo silver]

What a concept - designing a home around efficient energy use.
What did the architect have to say about your idea? (Or did you do that part too?)

[jayman]

Oh gawd, if you were to leave it up to an "architect" the entire home would be glass, with some artsy-fartsy garnish on it

Yes, I also had to do the plans myself. There are a variety of computer programs you can purchase to do so.

I've had good luck working with Beaver Plastics, maker of the Logix Insulated Concrete Form building system

LOGIX ICF

I go for very simple plans that maximize usable space. No fancy roof lines either, those valleys are a potential source of leaks down the road: simple gables work best.

If you spec such a home with 12 inch ICF blocks, the resulting R value and solid feel of the home are beyond belief. Canadian window companies like All Weather Windows or Polar Windows make the proper tri-pane window with a PVC jambliner designed for such a wide wall