Venting and the cost of Gas vs Electric Water Heaters

Does the need to vent a gas water heater get factored into the equation? Having learned a bit about water heaters in the last few days, I see that the vent from my current heater (4") goes off to the chimney. But, unlike the one from my furnace, this one has nothing to stop warm air from exiting all the time. (The furnace has a shield that opens and closes as the furnace cycles. In fact, one cold winter day I found out that the furnace wouldn't fire because a bird had flown into and blocked that mechanism. I soon had that cage thing installed on the top of the chimney.)
Since the vent is not sealed to the water heater but sort of sits on top with an opening of about an inch around it, it seems that warm house air is free to move out and cold air is free to come in.
I'm guessing that the air movement is pretty static unless the heater is on. The vent is at the bottom of the chimney and so is protected from direct winds. Still, after insulating everything in the house to hold down heating costs, a direct passage in and out is a little disconcerting.
As an aside, I'm putting in a Carbon Monoxide detector. I never bothered before because the furnace has an automatic CO shutoff and I didn't think of the water heater as a potential source for CO; I thought of it more as the vent from the electric dryer. That thinking has changed. Obviously it is no where near as dangerous as the furnace, but not to be taken lightly either.
Hmm. There is another thought. I wonder if I'd save money by installing a gas dryer rather than an electric one? Probably not enough to justify replacing a working dryer for over $600.
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Sure, its a vailid factor. Of course, it depends where the WH is located. If it's in a basement, which is more typical, then this is less of an issue than if it's in a living space. How big of an issue is questionable. In any house, you want some air exchange and most rely on some leakage, as opposed to using a heat exchanger.
Along the same lines, what about the air that moves up through the water heater even when its not burning? I would think that's one of the major standby heat losses, unless the flue up the middle is insulated from the tank around it?
The solution, of course is one of the new high efficiency WH that are direct vent.

In most areas, gas is cheaper as a fuel than electric. But for a typical family, I wouldn't replace a working AC one with gas with the idea that it's going to pay off.
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Working on my water heater recently, I think the losses are higher than just room air. It seems to me that the vent is actually carrying away air heated by the internal heat exchange surfaces of the heater, thereby cooling the heated water. Stick your fingers in there when the burner is off. On mine, there is significant warm air coming up inside the heater.
Bob
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This is an OT reply. I really mean it, Off Topic, way out in Left Field. You don't have to read this if you have blood pressure problems. Honest.
If one lives in Suburban Mid-West, your home and the land that your home is on is most likely yours. If a DIY really messes up with NG, Propane, Venting, CO poising, then only the family involved is, well, ah, involved.
But in many major cities, NYC in this thread, a home owner is just as likely to be a "Condo" owner. That is really an apartment building that was converted into a "Condo". Yes, the owner's home is his' / her's / their's but the potential is more than one home is involved if the DIYer screws up. A natural gas fire in one home will just as likely affect more than one other Condo home.
NYC is NOT known though out Western Civilization as having too few lawyers, nor having a population reluctant to phone a lawyer with little or no cause.
The issues of a high density population living in a very high cost of living environment creates issues of municipal oversight that is incomprehensionable to many of my neighbor in suburban Detroit. And I only lived in Baltimore, which was a lot lower population density than a some of the Boroughs of NYC.
Simple example: the chimney that a Hot Water Tank vents to. Is this chimney dedicated to that home only? Is it a converted fireplace chimney? Is there a problem with the "cold air column" of an outside wall chimney during winter? If the water tank's T&P valve pops, is the drainage water going to affect any other home owner in the Condo?
If the OP was living out on Long Island in one of them Levittown places, I would very much encourage him to DIY the hot water tank. He will need the knowledge and the confidence building from doing so for later in life projects.
(This is just IMHO, from my experience in Baltimore) But if He is living in a condo situation inside NYC-- There is a risk (outside chance) a neighbor might call a lawyer to demand that the installation be halted, and wait for a licensed plumber and inspector to do the installation correctly before the gas burner could be turned on... well that is a risk in lawyer packed NYC. Plus, and this could be worse, I think the neighbor just might be able to force the OP to pay for the Lawyer on top of going without hot water when his wife returns.
Anyway just my OT opinions. Anyone may ignore my rant if you choose. Now if you will excuse me, I need to find some plate steel for my butt when the flaming starts.
Phil
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On Wed, 24 Oct 2007 17:03:37 -0400, "Phil-In-Mich."

Good answer, not OT and worth thinking about. Not a condo but close enough to other homes to affect them. There was a brownstone that blew up a year back or so that did significant damage to other homes. The guy responsible didn't care though because he died as I recall. BUt there was more to that story, there was some love gone bad story and I think he intentionally blew it up.
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dgk wrote:

Hazardous amounts of CO are NOT generated in a properly functioning gas flame. The chances of a gas water heater flame being deprived of sufficient oxygen such that it produces untoward quantities of CO instead of CO2 is immeasurably small.
I, for example, grew up in a home with gas space heaters. Aside from a reluctance to remove my shirt in public or expose my tongue, I'm okay.

You will almost certainly save money.
Washers and dryers can be found for free on Craigslist.
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Bullshit...
More bullshit...
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WARNING: during one of my remodels, i had them put in a new gas, energy efficient water heater..................(it vents to the outside)
loudest damn thing i have ever heard(sounds like a rocket taking off)...............................wish i could get my money back!

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