On Demand HOT water

Ron Conrad

I am building a new home soon and think the on demand HOT WATER sounds perfect but have heard a few contractors say I have installed 2 systems and removed 2 systems. Is it worth the time to look into or just go conventional.

2200 sq/ft main floor(Kitchen, 3 bedrooms and 2 bath) with 2200 sq/ft bsement (2 bedroom and a bath).

Likely 4 full time occupants using upstairs for the next several years and no more kids to follow (just relatives and friends using the basement bedrooms).

polka

On demand

My first question to add to this discussion, is, is a recycle line possible here, and if so, wouldn't that defeat the purpose of using the fuel only when you need it. The company i work for has clients who want their hot water now, that means intantly, it seems to me like that makes the on demand system not so attractive to this type of client. Its seems a bit drastic, but they pay to run that bronze pump, and if they 're only losing a degree an hour, with say indirect heating and storage, they don't seem to mind as long as the hot water is there, as soon as the fixture is opened. From what i've read and heard, the on demand tankless flash heat systems have very strong selling points, from ease of installation, modular repair, space requirements, and suppossedly endless hot water(if you don't mind waiting). It is of my personal opinion, most people don't realize they even have a vacation setting on their water heaters, and certainly nobody drops the low temp setting on the their heaters before they leave the house in the morning, then there definetly would be waiting for hot water. With the obvious concernes we should have for natural fuel supplies, financially and enviromentally, i think most folk would and are so used to waiting for the hot stuff, that if they knew they were saving money by waiting, they wouldn't mind. The question really should be, do you have to live in Europe for this to work? I'm curious myself to know who out there is installing these units, how they are working and customer response. Are Americans scared of this technology?, I don't see any Levittown/Radiant type of situation that would make us all so hesitant toward something that seems to in theory, work quite well. If i had my own company, i would intall one in my own home, or a customer/friend who was willing to be the guinea pig, right away. the sooner you get one in, the longer test you can run, which will back you up every time you are questioned on the topic. Just like this cite, its about teaching ourselves and others. I think i've convinced my brother-in-law to put one in, and i'm not even sure if i'm a proponent of the product or not. I am also interested in knowing more about the track record of this type of product, and i have heard the "two installed, two taken out" remark myself, but i'm curious if maybe, that is only American Urban Legend.

Jack_23

They work...

and yes if you put them far away from the point of use you will wait. Having said that, in the bigger houses, they are small enough to put in more than one unit. Long term economically practical as you eliminate the recirc, which is an incredible energy hog (that gets lost in the discussion when you maintaining hot water 24/365). The fact is, every mechanical system has a personality and on-demand WH's behave differently than a tank. A Rinnai will make 4.7gpm of 120f (70f rise)water 24 hrs per day. That is about 280 gph. They work and they will change the way America heats water because they make sense. Also, builders like them because they save space and they build by the sq ft. www.foreverhotwater.com

Gordo

On-Demand Water heaters

I installed one in my first house and used it for 13+ years. It required some ajustments. It did indeed have a differant "personality". It will crank out hot water as long as you have fuel and water. You can take an "endless" shower, then run uncounted loads of laundry, then run run run the dishwasher. BUT, don't even try to do any two hot water draws at the same time, unless you get a really big wall-hung unit. It just won't have the output. And if you don't draw enough flow, the unit will shut off. That can get exciting while you're in the shower. That usually happens during the summer when the incoming cold water temperature is higher and causes the temperature rise curve to drop below the minimum flow curve. Yes, it did require adjustments, timing, and tweeking. It was not just set and forget. I'd get two units. One for your basement bathroom(s) and one for the rest of the house. They are more expensive per unit than, say, a 75 gal. gas tank type, but they should last longer. This assumes you've got gas. Electric on-demand heaters...well, I wouldn't bother.

lchmb

here's my two cent's...

If I overpay do I get change? j/k...:) I have personally installed a number of these unit's..The Rinnia and Aquastar are two big unit's in my area. I have used these not only for hot water but also for radiant zone's. I have had excellent feed back so far from my customer's. I personally find the Rinnia an excellent product, excellent support is available as well. Now as to the constant loop, you could also, if you wanted, do this with the Rinnia with it's temperature control system. Why you would do this is beyond me, but you could. If the system is set up proper and thing's are located in a central mannor you would in my opinion have many year's of happy service with a large volume of saving's on your part...
And I have had a number of customer's who have used multiple shower's with the Rinnia with no problem's, the water flow will slow slightly to compensate...

Larry Weingarten

tankless

Hello: Back in 1996 we wrote an article that might help you. See link. Some things have changed, but only a few. Read it and see what you think. http://homeenergy.org/archive/hem.dis.anl.gov/eehem/96/960510.html

jw

Eliminate energy wasting recirc

Big house, lotsa copper radiant heat tube (read recirc line) and yer boiler running a lot more than it should.

For about the same $ as the avoided pump, control, copper pipe and the insulation that SHOULD be used but often is not, you can install a smallish (14kW?) instant electric water heater in line with the primary hot water source and kill a whole flock of birds with one stone.

Under counter on in a closet in master suite. Gives instant hot water to tap and to shower till the heat gets to the suite. Then the electric unit modulates down to zero.

Cool part of this is that if the primary source is running out of "steam" the instant/ modulating (seisco) water heater at the suite starts to seamlessly pick up the load.

Do I hear customer satisfaction, no callbacks here?