Instant Hot Water or Hot Water Recirculation

[redpoint5]

It takes about 60 seconds of running the water in the kitchen for hot water to begin flowing, and about 90 seconds to reach the master bath.

What do you think of the recirculation pumps to keep the water warm? How much energy would you think I might loose using a system like this? A timer can be set to recirculate at set times of the day when hot water is likely needed. A dirty calculation tells me I might save 2000 gal of water with such a system.

The other option I'm considering is an instant hot water heater installed under the kitchen sink. It stores about 0.3 gal of water at 170 degrees to be used for tea, or short bursts of hot water to clean dishes. My wife drinks tea every day, and it would be convenient for her to have instant hot water instead of using a tea kettle. Again, how much energy is wasted in keeping this water hot all of the time? Would the energy expenditure be insignificant (less $2 or less /month)? I could put the instant hot water on a timer too.

Would you install the hot water recirculation, instant hot water, or do nothing?

Instant hot water

Hot water recirculation

[Frank Lee]

No way to put the main water heater close to where it's needed? I was lucky on my house; the water heater is in the basement directly below the bathroom. The run from heater to showerhead is probably 10 feet so very little cold water has to be run outta there. It isn't much further at all to the bathroom sink, the washing machine is about 5 feet away from the water heater, and the only other hot water demand is the kitchen sink which has the longest run at, oh, 20 feet. Even though my plumbing is nicely concentrated towards the center of the house I have gone through and put those foam sleeves on the hot water lines, and also on the sump discharge line because that one used to form condensation in the summer. I cannot say how much they help as the system was always pretty good anyway... but they have to help! They just have to!

Maybe that house is just too big.

[redpoint5]

That reminds me Frank, another thing I was considering is to install a tankless gas water heater in the crawlspace below the house in a central location. I'm not sure if codes would allow for this, but I imagine it's ok since the heaters are allowed in living spaces. This would be my preference so that I can free up some space in the garage.

My crawlspace is difficult to maneuver in since it's only 4ft high at the largest end. I'm envious of those with basements... they aren't very common in the NW.

And yes, I do have too much space. 4bd 2.5 bath 2100 sq/ft just for me and the wife. I had been renting out the other rooms the last 3 years of my unmarried life, but she ruined my plan of retiring at 50 and marrying a 25 year old; and yet I couldn't be more satisfied.

[SoobieOut]

I did the hot water recirc pump about 5 years ago. Works great, and you set a timer for the pump to run when you need hot water.

I did have to replace the valve at the end of the line a year ago. But with the hard water in our area, I figured it would clog.

[roosterk0031]

As much as it seems a waste to dump cold water, you'll never recoupe the cost, it will actually cost you more. First you have to pay for it, and second your water heater will run more. Water is so cheap the volume of water you dump is tiny.

Electric's OK if your main heater is electric, if you main heater is gas, better to dump the water.

Best bet for result you'd like would be to replumb using pex tube so you cut the volume of water in the pipe by 2/3s.

[Cobb]

How about work on the back end for savings vs the front end?

Instead of instant hot water at the tap, why not consider a grey water setup so you can send water to your garden, lawn or a rain barrow for later use?

4ft crawl space? I would kill for that. My crawl space is just enough for a small boy to wiggle through or a cat.

[redpoint5]

I'm considering various options not only to save resources, but also to make the wife happy. If instant hot water only costs an extra $1/mo, then it would be worth it to give my wife hot tea the moment she wants it. It also makes washing greasy dishes easier to hit it with some hot water. It wouldn't be worth it to me if it cost an extra $5 in electricity though.

A recirculating pump or an instant heater run about $150.

As rooster mentioned, the water is cheap. It's the convenience I'm after.

Ultimately, I think I'll wait until the gas heater in the garage dies and then buy a tankless unit and mount it in the crawl space.

Cobb- My crawlspace is a max of 4ft. 2/3 of it requires army crawling, perhaps 1.5 ft of space... annoying enough that I haven't finished wiring my surround speakers in the living room.

[Frank Lee]

Take the low-flow aerators off to get that hot water there NOW rather than later. There's your free water circulation.

[Giovanni LiCalsi]

I'm a retired plumbing contractor.
The best solution is to buy a hot water circulator pump kit for an under sink installation.
The kit has, of course, a circulator pump, check valve, thermostat, sensor and 2 double-port anglestops. The extra ports on the valves will supply water to the sink valve. The kit can be installed on the bathroom or kitchen sink, usually the farthest sink from the water heater.
All you need to do is to plumb the water flex lines into the hot and cold water lines under the sink and plug the 110volt circulator into an electrical outlet.
The circulator pump will be located in between the hot and cold anglestop valves with the pump flow direction pointed towards the cold water anglestop valve.
It simply circulates hot water from the hot water anglestop to the cold water anglestop until the temperature sensor detects hot water, then the thermostat shuts off the pump.
This is simple and cost effective. Easy DIY project.

[wdb]

By pumping hot water into the cold water lines, if one were to then desire cold water, would one get warm or hot water instead? If so that solution is not for me. I want my cold water to actually be cold.

If it's hot water for tea you're after, why not do something simple like a hot plate and a timer.