Need gas water heater

Phantom · 09-13-11, 10:16 PM

Today I get a call from my better half saying that the basement has water all over it, turns out the water heater is leaking.

Now I need to look into getting a new heater I believe the current one is a 40gal I feel that that is larger than is needed but want to know what others suggest. The situation is two people live in the house the most hot water we will use is two showers in a row unless we have a guest (up to four showers). We need to insure that what is selected will not negatively impact resale value in the next 5-7 yrs. I have thought a little bit about adding hydronic heating later but that is not very likely right now.

The heater must be gas as that is what I want and have currently the first full month of gas cost ~$3 for heating water and cooking food plus doing 3 loads of laundry (gas drier).

What is size do you recommend?
I'm not sure if I want to go tankless or not.

Ryland · 09-14-11, 12:04 AM

Pretty much any gas water heater that has a forced exhaust vent fan is going to be pretty decent, I really like our 90% efficient AO smith Vertex gas water heater but it's cost is a bit high for most people, it should last longer then nearly any other water heater out there tho and it has stubs for hydronic heating.

Daox · 09-14-11, 08:17 AM

I agree with Ryland. Both the power vent tank heaters are very nice as well as an on demand units. They both have their tradeoffs. Power vent units obviously have standby losses which will depend on the amount of insulation the tank has. Of course you can reduce these losses with additional insulation. On demand units have no standby losses, but their AFUE is only about 80%. I'm not sure of the AFUE for most power vent units, but Ryland's is obviously higher. My guess is these two will just about be a wash.

If I had to choose I'd probably go with an on demand. However, most require a larger exhaust pipe or a power vent which adds cost. Make sure to look at the install manuals before you buy one. I'd also find one with a dedicated air intake so it doesn't use warm house air to feed the flame.

Ryland, does your power vented tank have a dedicated intake?

herlichka · 09-14-11, 09:09 AM

I have worked on several new homes with on-demand hot water heaters, and for the most part, they seemed to work well, even very well. But one system seemed to have mineral deposit issues almost immediately. I don't remember the brand name, but it was propane fired, and heated water from a drilled well. it served dual purposes, domestic hot water and hydronic heat, pex in concrete slab. I don't know if the well water was entirely to blame, or if the extra cycles for the heating load accelerated the deposits, but this has always been in the back of my mind. I seldom see the homeowners, so don't know how, or if, the problem was ever resolved, when we finished the house the heating contractor was still trying to figure it out.
Anyone else seen this problem?

Daox · 09-14-11, 09:57 AM

Yeah its a common problem in areas with hard water. There is a very easy fix to it. You simply hook up tees right before the water heater so you can flush it when need be. You just run some vinegar through it to clean things up every few months depending on how bad your water is.

Here is a video example AC Hacker posted in my thread about installing an electric on demand heater.

Tankless water heater flushing cleaning - YouTube

iamgeo · 09-14-11, 10:00 AM

Water is very hard in this part of Texas. I have a kinetico water softener and an electric tankless water heater. There have been a couple times when the Kinetico was not working, my fault, not the units. Anyway, When the softener was not working there were white "things", kind of like plastic, that were clogging the screens on the faucets. Figured out it was when I used hot water. I called the manufacturer and was told that the heating elements had a coating on them that reacted with the minerals in the water when they got hot. Said they were cheap heating elements that the original manufacturer had used. Was also told that I MUST use a water softener with the tankless.
I bought 2 new heating elements and tested them by bypassing the Kinetico. The faucets did not clog up.

Moral of the story. Use a water softener and make sure heating elements are not cheap.

Ryland · 09-14-11, 10:06 AM

A friend of mine services Bosch on demand water heaters and he has a few people who he has to acid flush their water heater every year or two because of hard water, so if you have hard water issues it might not be the best choice for you unless you don't mind flushing it, if that is the case then you might as well plumb in the valves and pump when you install it.
I also remember reading that some of the best on demand water heaters were around 60-70% efficient, cheap ones are worse.

Tank type gas water heaters that have forced exhaust tend to have less stand by loss because the flue is smaller and the fan slows down the convection, you can have as much insulation as you want around the out side but if you still have an open, uninsulated flue going up the center you are going to get heat loss from there, but a tight fitting fan assembly is going to slow that leak point, having a fan also allows you to put a timer on the tank because it will not turn the gas on without the fan (electric ignition tends to be standard on power vented gas water heaters) so if you both work 9-5 and sleep 10 to 7 you can set it to turn on and just heat a single batch of water instead of keeping a tank of water hot all the time, this saves you the stand by losses.

Daox · 09-14-11, 10:22 AM

Quote:

Originally Posted by Ryland

I also remember reading that some of the best on demand water heaters were around 60-70% efficient, cheap ones are worse.

I'm curious where you read this? The energy star list for on demand gas water heaters has tons of them with 80+% efficiency.

gasstingy · 09-16-11, 01:53 PM

As there are others giving really good advice on the water heater, might I suggest installing ultra low flow {as in 1.5 gpm} shower heads in the house. Then, you can get more minutes of shower usage out of a tank of water. On those infrequent occasions where there might be 4 in a row, you're better covered.

Also, let me throw this out there. I live every day with a standard 50 gallon natural gas HWH. My wife and I could run the dishwasher, both of us take showers and our daughter take a shower and we never ran out of hot water. {The daughter is now married and gone.} And that was before I changed to a 1.5 gpm shower head in the master bath. Gas seems to recover very quickly, but that's a very unscientific personal observation.

Ryland · 09-16-11, 09:41 PM

Quote:

Originally Posted by Daox

I'm curious where you read this? The energy star list for on demand gas water heaters has tons of them with 80+% efficiency.

I read it in one of the bits of paper work that was talking about incentives for new water heaters and how they were not covering on demand water heaters because they were not efficient enough and their payback was sometimes as long as the life of the water heater.
But I did just look at the Energy Star list and am a bit confused now, as I do agree that there are a handful of good on demand water heaters out there.

09-13-11, 10:16 PM	#1
Phantom Apprentice EcoRenovator Join Date: Sep 2010 Location: Louisville, KY Posts: 101 Thanks: 13 Thanked 8 Times in 7 Posts	Need gas water heater Today I get a call from my better half saying that the basement has water all over it, turns out the water heater is leaking. Now I need to look into getting a new heater I believe the current one is a 40gal I feel that that is larger than is needed but want to know what others suggest. The situation is two people live in the house the most hot water we will use is two showers in a row unless we have a guest (up to four showers). We need to insure that what is selected will not negatively impact resale value in the next 5-7 yrs. I have thought a little bit about adding hydronic heating later but that is not very likely right now. The heater must be gas as that is what I want and have currently the first full month of gas cost ~$3 for heating water and cooking food plus doing 3 loads of laundry (gas drier). What is size do you recommend? I'm not sure if I want to go tankless or not.

09-14-11, 08:17 AM	#3
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	I agree with Ryland. Both the power vent tank heaters are very nice as well as an on demand units. They both have their tradeoffs. Power vent units obviously have standby losses which will depend on the amount of insulation the tank has. Of course you can reduce these losses with additional insulation. On demand units have no standby losses, but their AFUE is only about 80%. I'm not sure of the AFUE for most power vent units, but Ryland's is obviously higher. My guess is these two will just about be a wash. If I had to choose I'd probably go with an on demand. However, most require a larger exhaust pipe or a power vent which adds cost. Make sure to look at the install manuals before you buy one. I'd also find one with a dedicated air intake so it doesn't use warm house air to feed the flame. Ryland, does your power vented tank have a dedicated intake? __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

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09-14-11, 12:04 AM	#2
Ryland Master EcoRenovator Join Date: Mar 2009 Location: Western Wisconsin. Posts: 913 Thanks: 127 Thanked 82 Times in 71 Posts	Pretty much any gas water heater that has a forced exhaust vent fan is going to be pretty decent, I really like our 90% efficient AO smith Vertex gas water heater but it's cost is a bit high for most people, it should last longer then nearly any other water heater out there tho and it has stubs for hydronic heating.

09-14-11, 09:09 AM	#4
herlichka Apprentice EcoRenovator Join Date: Oct 2010 Location: Simcoe County, Ontario, Canada Posts: 102 Thanks: 11 Thanked 15 Times in 10 Posts	I have worked on several new homes with on-demand hot water heaters, and for the most part, they seemed to work well, even very well. But one system seemed to have mineral deposit issues almost immediately. I don't remember the brand name, but it was propane fired, and heated water from a drilled well. it served dual purposes, domestic hot water and hydronic heat, pex in concrete slab. I don't know if the well water was entirely to blame, or if the extra cycles for the heating load accelerated the deposits, but this has always been in the back of my mind. I seldom see the homeowners, so don't know how, or if, the problem was ever resolved, when we finished the house the heating contractor was still trying to figure it out. Anyone else seen this problem?

09-14-11, 10:00 AM	#6
iamgeo Apprentice EcoRenovator Join Date: Aug 2010 Location: Lakehills, Tx Posts: 168 Thanks: 4 Thanked 10 Times in 9 Posts	Water is very hard in this part of Texas. I have a kinetico water softener and an electric tankless water heater. There have been a couple times when the Kinetico was not working, my fault, not the units. Anyway, When the softener was not working there were white "things", kind of like plastic, that were clogging the screens on the faucets. Figured out it was when I used hot water. I called the manufacturer and was told that the heating elements had a coating on them that reacted with the minerals in the water when they got hot. Said they were cheap heating elements that the original manufacturer had used. Was also told that I MUST use a water softener with the tankless. I bought 2 new heating elements and tested them by bypassing the Kinetico. The faucets did not clog up. Moral of the story. Use a water softener and make sure heating elements are not cheap.

09-14-11, 10:06 AM	#7
Ryland Master EcoRenovator Join Date: Mar 2009 Location: Western Wisconsin. Posts: 913 Thanks: 127 Thanked 82 Times in 71 Posts	A friend of mine services Bosch on demand water heaters and he has a few people who he has to acid flush their water heater every year or two because of hard water, so if you have hard water issues it might not be the best choice for you unless you don't mind flushing it, if that is the case then you might as well plumb in the valves and pump when you install it. I also remember reading that some of the best on demand water heaters were around 60-70% efficient, cheap ones are worse. Tank type gas water heaters that have forced exhaust tend to have less stand by loss because the flue is smaller and the fan slows down the convection, you can have as much insulation as you want around the out side but if you still have an open, uninsulated flue going up the center you are going to get heat loss from there, but a tight fitting fan assembly is going to slow that leak point, having a fan also allows you to put a timer on the tank because it will not turn the gas on without the fan (electric ignition tends to be standard on power vented gas water heaters) so if you both work 9-5 and sleep 10 to 7 you can set it to turn on and just heat a single batch of water instead of keeping a tank of water hot all the time, this saves you the stand by losses.

09-16-11, 01:53 PM	#9
gasstingy Journeyman EcoRenovator Join Date: Feb 2010 Location: Arab, AL Posts: 491 Thanks: 109 Thanked 49 Times in 43 Posts	As there are others giving really good advice on the water heater, might I suggest installing ultra low flow {as in 1.5 gpm} shower heads in the house. Then, you can get more minutes of shower usage out of a tank of water. On those infrequent occasions where there might be 4 in a row, you're better covered. Also, let me throw this out there. I live every day with a standard 50 gallon natural gas HWH. My wife and I could run the dishwasher, both of us take showers and our daughter take a shower and we never ran out of hot water. {The daughter is now married and gone.} And that was before I changed to a 1.5 gpm shower head in the master bath. Gas seems to recover very quickly, but that's a very unscientific personal observation.