 | ||||
| ||||
| | ||||
| ||||
| Moderated by: Admin |
|
||||||||||||||
| Cold-water sandwich | Rate Topic |
| Author | Post |
|---|
| Posted: Thu Jan 21st, 2010 07:18 pm |
|
1st Post |
|
elenano Member 
|
I'm posting this on behalf of somebody who The Tank rejected when he tried to sign up. That happens a couple of times a year. I told him about the tankless that has a small tank, but couldn't remember the brand. Randy Schuyler I have read in Water Heater Rescue and other sources about the "sandwich effect" that typically occurs when a tankless water heater is in normal operation. To address this circumstance in a fairly large family home with 4 baths, does it make sense to install the tankless unit in series with the inlet of a (smaller) tank type heater? I think it would provide some buffer or "capacitance" to bridge these sandwich events. I should also mention the present hot water system includes a recirc pump. Of course, such an arrangement would certainly cut into some of the cost savings a tankless unit offers... I welcome your discussion on this topic Fazer
|
||||||||||||||
| |||||||||||||||
| Posted: Fri Jan 22nd, 2010 11:40 am |
|
2nd Post |
|
energyexpert Member
|
Randy, Try http://www.eternalheater.com. David
|
|||||||||||||
| ||||||||||||||
| Posted: Fri Jan 22nd, 2010 05:55 pm |
|
3rd Post |
|
elenano Member
|
David, I'm not sure that's what he's looking for. I know there is a tankless maker that came up with one with a two-gallon reservoir or something like that, and I don't think it's the Eternal. Then there is the issue of his recirc system and all that.... Randy Schuyler And then I thought, "Well maybe Eternal HAS come up with something like that, so I went to the link, but it's not the right one for the Eternal water heater, which is made by Grand Somebody or other. The site appears to be newly registered and has a bunch of links to other products. The right link appears to be http://www.eternalwaterheater.com. That heater does have a tank in it for the cold-water sandwich. I'd still like to see Larry's comments on Fazer's overall system. Last edited on Fri Jan 22nd, 2010 06:04 pm by elenano |
||||||||||||||
| |||||||||||||||
| Posted: Sat Jan 23rd, 2010 07:20 pm |
|
4th Post |
|
eleent Member
|
Hello: What equipment is best really depends on how it is to be used and what the expectations are. A small tank after the tankless heater SEEMS to make sense, but it will likely be electric. If there is a recirc line to it, you wind up heating the hot side plumbing with electricity, which gets real expensive. A rule of thumb is that a 24 hour recirc triples your hot water energy bill. Maintenance is also a consideration. Tankless heaters are basically mini boilers and need maintenance yearly. Do they save enough in energy to warrant spending for a yearly visit from a plumber? Depends on water usage and quality and what the plumber charges. Certainly a technically inclined person could maintain his/her own heater, but how many do? Navien is a brand that comes with a small tank in it, (poorly insulated) and this eliminates the cold water sandwich. It also is a condensing heater which makes in much more efficient and less expensive to install. The vent can be PVC pipe. Takagi has a condensing unit as well and certainly more good technology is coming down the line. I'll predict that we'll see two basic models; one for retrofit and one for new construction. The retrofit must work with a 1/2" gas line while the new construction model will be able to use a 3/4" gas line. This means the retrofit model will need a bigger tank than the new construction model. Regardless of the heat maker, making the plumbing system and fixtures more efficient will likely give a quicker return on investment. It's similar to the solar collector vs insulation discussion. Solar, looks good on the roof, but is a little silly to hook up to an inefficient house. A small solar system on a very well insulated house makes more sense as the insulation/air sealing costs roughly a fifth to a third of what solar costs per unit of energy saved. Pipe insulation and low volume plumbing are not sexy, but once in place they normally don't fail, they have good returns and add to comfort and the enjoyment of a home. Does that cover it?  Yours, Larry ps. I'd be scared to use only one tankless in a four bath home. Too much opportunity for it to be maxed out. Tankless though is a very good fit for tub filling, which would allow the heater for the balance of the system to be a lot smaller/ more efficient. Look into http://www.gothotwater.com for recirc strategies.
|
|||||||||||||
| ||||||||||||||
| Posted: Mon May 24th, 2010 02:39 pm |
|
5th Post |
|
GMTX Member
|
Here is a manufacturer new to the US market (1 or 2 years I think) that has a small tank as part of the "tankless" unit. It does appear to address many of the shortcomings of tankless water heaters, however, as noted on this site, the economics really don't work for most applications. http://www.navienamerica.com/
|
||||||||||||||
| |||||||||||||||
| Posted: Tue May 25th, 2010 03:14 am |
|
6th Post |
|
elenano Member
|
Navien was the brand I was trying to remember in my original post. Randy Schuyler
|
|||||||||||||
| ||||||||||||||
| Current time is 10:53 am | |
| thetankatwaterheaterrescue.com > Forums > The Tank > Cold-water sandwich | Top |
