Powered direct-vent gas water heater recommendations?
My water heater is on the last legs (just started to leak). The current unit is an atmospheric vented unit that is located in the basement. Based on Martin’s article (www.finehomebuilding.com/design/articles/the-water-heater-payoff.aspx) it appears that a power direct vent (sealed) or gas condensing is the best way to go for a basement location. Besides minimizing drafting and makeup air issues, I like that I can eliminate the vent to the roof.
While there is decent information on atmospheric and some power vented water heaters, information is sparse on the power direct-vent variety. My questions:
1) Any recommendation on brands/models? Any to stay away from?
2) Is it worthwhile to go to the condensing units? Prices seem to have come down since the original article (~1,500-2000). Are these more prone to failure?
3) When sizing a unit, is the first hour rating really the best way? Are there other factors I should consider (besides physical limitations)?
4) Is there a good way to calculate payback on these based on my own use?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
This unit is by far the best buy . Quality materials , made here , low maintenance, proven technology , modulating / condensing . Yes condensing is more efficient , the colder the incoming water the more energy can be used and not going out the flue . As far as I know , this is the only modulating output condensing water heater , cost is comparable to non modulating units such as AO Smith Vertex .
http://www.htproducts.com/phoenixldwaterheater.html
That phoenix unit seems too good to be true. How does the modulating output work? I'm having trouble finding any real world experience or reviews on the web. How are you quantifying this as being a best buy versus the more common makes like Bradford-White, Rheem, AO Smith, etc?
Modulating technology mixes an appropriate amount of air with the fuel , similar to tankless units and early modulating low mass boilers . The low end modulation on this particular unit is 25,000 BTU and as you would imagine the high end is 76,000 . The sensor in these units is placed at the middle level of the tank where as storage type heaters have the sensor at the bottom . The sensor reads the desired and set tank temp and modulates the burner in an attempt to keep the temperature at that setpoint . cold water flows in the bottom and is heated rapidly . Another control strategy that should be used with all heaters is storing at a minimum of 140*F and utilizing a 1017 ASSE type mixing valve . This will insure that legionelosis bacteria are exterminated and mixing 140 - 160* stored water with 50 cold water to achieve your 120* temp effectively increases the output of any storage type water heater . This will become common knowledge in 2015 when the new water heater rules become mandatory . The fact that you can find anything bad on the web is a good thing . I am quantifying this as a best buy because I am a plumber , consultant , designer of high efficiency heating and hot water systems . None of the earlier mentioned brands come close to the quality in material and workmanship , longevity and technology . HTP answers to no board of directors aas it solely owned by an individual who thinks ahead and his products attest to that . Listen , the market will continue to allow the big 3 to sell their wares to those who care only about price but they soon will realize that this and other competing products that are far better are selling for the same price point . When HTP got the new mandatory requirements that are coming into play they had no work to do while the others had to re tool and add new controls and the like . HTP only manufactures high efficiency products , there is only one unit they make with a sub 90% AFUE . Try to find another manufacturer that makes that claim and has been doing it as long as HTP . As a side note , while many may not have heard of HTP they are the second largest purchaser of 316L stainless steel in the world lead only by the US Navy .
In short , they had the foresight to make better products that are of the highest quality before it was cool .
Thanks for the detailed response. I read through the manuals and watched the videos online last night. One area that was different from other manufacturers was in reviewing your water chemistry. My PH is fine, but the city reports its average water hardness as 11 grains per gallon. I'm not sure about the Total Dissolved Solids (TDS). Based on their hardness specs, I would need to also install a softener to get my water hardness between 5 & 7 grains. Is this a unique concern of HTP due to their design?
That is simple . HTPs heat exchanger is inside the tank as opposed to everyone elses' which is under the tank . Hardly the optimum placement for a heat exchanger . Yes , it is unique to HTP and since they offer a 10 year warranty to everyone elses customary 6 it is worth the investment .
So how exactly do you get to their specified hardness range between 5-7 grains per gallon with a softener? This sounds somewhat unattainable with residential equipment.
Per the manual:
"If the hardness of the water exceeds the maximum level of 7 grains per gallon, water should be softened to a hardness level no lower than 5 grains per gallon. Water softened as low as 0 to 1 grain per gallon may be under-saturated with respect to calcium carbonate, resulting in water that is aggressive and corrosive."
If your city water has an AVERAGE hardness of 11 grains it does not matter what heater you purchase , they're all gonna have very short lives . 11 grains falls right in the wheelhouse of VERY HARD as far as classification goes , hard is in the 3.5 to 7 range and slightly hard from 1 to 3.5 . Your towns average hardness is a full 2 scales upward on the hardness scale . You should move . No matter what heater you buy I suggest something like a Pelican whole house filter and softener . While you're at it you might as well purchase a good quality , long lasting , efficient heater like the HTP or something comparable if you can find anything like it .
HA ha. moving is out of the question. And based on the map (http://www.water-research.net/images/hardwatermap1.jpg), no matter where I go, escaping hard water is difficult. So yes, it does sound like I may need to soften the water regardless of the water heater equipment I choose.
Now back to the original question. It is my understanding water softeners are an all or nothing operation. Yet, HTP specifies that the water should have 5-7 gpg hardness and definitely not 0 to be eligible for its warranty. So how do you dial in your hardness to meet this spec?
I'm curious on the recommendation for the Pelican system. On the face of it, salt-free solutions sound good. However, while I'm no where an expert, the claims of the unit appear to very exaggerated. For instance, from my research, the process Pelican uses doesn't actually have any ability to actually soften the water. Additionally, I have read that the material it uses has a lifespan of about 5 years and not the lifetime it claims.
Correction Brad . Something like a Pelican system is much different than go buy a Pelican system . Water softening and treatment require lab tests to determine exactly what one is dealing with and how to address it with what equipment . In my house , I have a well which I will never give up no matter how long the local utility and their AHJs have a curbstop at my property line and tell me I must hook up . Yeah , see me in court ! I employ a Lancaster system that was designed specifically for the TDS , contaminants or whatever nasties lurk in the ground below my property . By the way I can enter a specific hardness on that unit , I have HTP products in my home as I test many different arrangements and capabilities before I recommend or install them in others' homes , and I have yet to suffer a failing HX on any of the units I have had installed .
Please don't mistake a direction given by one to types of equipment as a recommendation . The only things I recommend for your initial question and topics that have arisen are HTP water heating products , lab testing of your specific water and prescriptive softening and treatment of the water you and your family will use inside your home . I like Lancaster treatment and softening equipment personally .