Advice on Power Vent Hot Water Tank?

[Jeremy Milam]

Our hot water tank is 20 years old and probably not going to live much longer, though there's always hope. My long term plan is to remove the chimney that is only used by the tank, as the furnace vents out the house side now.

So, I got two quotes for tankless and figured the payback would be....never. (Quotes were $3650 and $3685, we pay less than $5 a month for natural gas for our current tank)

Now I'm thinking of having a power vent unit installed that would also vent out the side of the house, making the chimney unused. One guy gave me a quote, and I've looked at Lowes and figure only about $400 more than a standard unit.

Any advice with these? Cons that I've read about so far are:
-15 amp motor makes some (little?) noise
-no hot water during power outages
-some say some units pull intake air from in the house and disrupt in house climate?

That's what I have so far, the last reason seems to be debated or only on some kinds, I'm not sure.

So, suggestions and advice, both in general and for specific brands/models to look at or stay away from would be appreciated.

Thanks,
Jeremy

[Randy Moore]

I have heard that it is cheaper to buy a new tankless when you have problems with the one you have if you go with tankless. I would go back in with a 40-50 gallon tank. It will last a lot longer than the tankless I hear. I do not have a tankless and just installed a 40 gallon about a month ago.
Just my 2cents

[Doug Colombo]

We have had a power vent water heater for 11 years. We have an A O Smith heater. To answer your questions based on our experiences:

- 15 amp motor makes some (little?) noise - There is some noise, but nothing that is objectionable at all. Water heater is directly under our bedroom, so if it was very loud, we would wake up

-No hot water during power outages - This is correct. If the blower can not power up, the safety system will not allow the gas valve to open, so there is no hot water. We live in the country and are on a well, so I put in an auto start NG generator system and made sure that the tank's power was connected to the transfer switch.

-Some say some units pull intake air from in the house and disrupt in house climate? In the 11 years that we have had the unit, I have not sen this issue. The water heater blower is only to assist the exhaust out the PVC pipe - it has nothing to do with intake air. Intake air is no different on these units than a standard water heater. There is a secondary heat exchanger that pulls additonal heat from the exhaust cooling it to the point that you need the blower to move it to the outside.

If I had it to do over, I would install the same system. Hope this helps !

[Jeremy Milam]

If I wasn't originally clear, we have a standard 50 gallon tank that vents through the chimney. I'm looking for an option that avoids the chimney.

Thanks Doug for the information. I keep seeing A. O. Smith mentioned. When I look at their site there are many choices that might work for my situation including:
ProMax Direct Vent
ProMax Power Vent
ProMax Power Direct Vent
Vertex Power Direct Vent
Vertex Power Vent

I need to research the differences, first thing I looked at is all have a 6 year warranty, I was hoping that had an option for a 12 year, much like you find of standard tanks at the big box stores.

Thanks!

[Michael Weber]

It's true that there is nothing cheap about tankless water heaters. From the special valve sets required for installation to the VERY expensive stainless steel double wall vent pipe. Probably won't make a difference in your decision but at least one manufacturer has a 94% efficient tankless water heater that uses standard PVC pipe for exhausting just as the newer 90+ gas furnaces do. Also, they make models (standard and 94% efficient) that are designed to mount outside and require no venting. I believe they are freeze protected down to -30 degrees but not sure if that's the correct figure. Models can be found at www.Rheem.com click on products.

[Matt Meiser]

We've got one, actually, our third. The original one for our house went bad after about 15 years so we put a new one in. Then last year we got natural gas and had to replace it because the manufacturer said it was not convertible. The second was in good enough shape that Habitat for Humanity came and got it as a donation to the ReStore. Our house doesn't even have a chimney so we really didn't have a choice unless we built a chimney chase somewhere.

None have been particularly noisy except when the fan went bad on #2 which the manufacturer replaced under warranty rather quickly. I want to say that was a Richmond but I can't remember for sure and the new one is a Bradford White. \

We also have a well so the power issue is a non-issue. I don't think they draw anything close to 15a by the way. I assume what you are seeing is the circuit requirement. You'll also have use of the water that is in the tank which should stay hot for a pretty good time.

As far as the airflow, a regular water heater is drawing air from the home as well. There can't be that much difference between the two.

[John M Wilson]

I'm no plumber, and I'll probably mangle the names of some of these things, but I might have an alternative for you...

My hot water heater does not use a chimney, but does not have the added complexity of the power vent. It uses a metal coaxial pipe that makes a 90 degree sweep from vertical to horizontal, and vents out the side of my house (It's in a corner of my garage). The vent through the side of the house is a square metal plate with a place for exhaust and intake.

My first one lasted about 15 years, and finding a replacement was not too hard. At the time, Lowe's did not carry a model like this, but Home Depot did (or vice versa). Other than the fancy vent (and the internals being isolated from the garage/workshop air) there is not much difference from a standard hot water heater. One advantage is that there is no electricity required to operate a power vent, so no power vent noise. (I did have a power vented furnace for a while, and I do not miss the extra mechanical noise of the fan firing up.) This unit also operates by pulling in outside air for combustion, which is not an issue for my garage installed unit, but might be a factor for some folks.

Sorry I do not have the exact name for this contraption, but at least you know that there is another alternative out there...

Good Luck!

[Jeremy Milam]

Thanks John, and everyone else.

John: is what you have similar to this from A.O. Smith:
http://www.hotwater.com/water-heater...t/direct-vent/

I'm still not sure what the difference is between their direct vent and power vent except for the use of power. When I google the differnce direct vent seems to be defined as through a chimney but the photo and description sounds like what John described.

[Bill Cunningham]

We installed a tankless 3 years ago. As far as I can tell it uses about $0.12 worth of gas a day, has a double wall PVC direct vent chimney, and draws it's combustion air from outside, same as my furnace. As far as power goes, it draws less than 3 amps according to the plate, and in an emergency you could just plug it into a 400 watt inverter hooked up to a battery. It's not on for more than a few minutes at a time, so the 30 amp draw on a good 12 V battery should allow it to be used for a good period of time..

[Brian Elfert]

The state of Minnesota has required power vent water heaters in new homes since 2000. I know the motor doesn't take anywhere close to 15 amps as I have it on a 15 amp circuit with some other stuff. If it did draw 15 amps you would need a 20 amp circuit as a 15 amp circuit can't actually sustain 15 amps continuously.

[Matt Meiser]

I ran down and looked at ours. The blower says 3.1FLA and the Honeywell gas valve says 0.1A. Since those are the only two electrical components, I would presume a 3.2A max load. The name plate on the WH says "less than 12A". I don't think ours is on a dedicated circuit either.

[John M Wilson]

Yes, that is very similar to the one I have... Mine is a Rheem Direct Vent.

No chimney required -- it vents out the side wall, just like the picture shows.

No blower required, either. Other than the fancy coaxial ducting, it's just like a conventional hot water heater.

I'm not sure if this is what you are looking for... maybe someone with plumbing experience will know the pros & cons...

[Eric Franklin]

I have a power vent hot water heater for the last 6 years and haven't had any issues. Another brand that is highly rated and built in Michigan is Bradford White which I currently have.

[Brian Elfert]

My parents just bought a new water heater. They seriously considered a power vent model because they figured it was higher efficiency, but they found that all water heaters are more efficient now. They decided not to deal with running a new pipe outside for the exhaust. My father said that all water heaters are electronic ignition now.

They didn't do tankless because my father said the payback was too long. Tankless probably makes more sense with a large family particularly with teenagers who take long showers.

[Bill Cunningham]

Tankless probably makes more sense with a large family particularly with teenagers who take long showers.

I have a wife and 3 daughters.. Without a tankless, they couldn't survive!