Water Heaters - Gas water heaters are expensive to operate

My home has your typical gas water heater with fresh air vent for combustion. Has anyone considered the additional cost to heat the home to offset the cold air introduced by the fresh air vent? Is seems to me that energy cost for a home could nearly be the same when using a gas water heater (with cold air vent) or the more expensive to operate electric water heater (with no outside air being introduced into the home). Comments?

If your water heater is located in a utility closet that is inside the "conditioned envelope" of your home then you have a valid point. In my area gas-fired water heaters are usually installed in unheated garages so the ventilation and combustion air isn't a factor in the heating (or cooling) of the living spaces of the home.

Nonetheless, for most areas the fact that electricity is way more expensive than gas usually offsets the apparent loss.

They make direct vent gas WH, which take combustion air from outside. The added costs of these is usually more than your energy loss, over the life of the unit.

furd:
You bring up an excellent point. Sadly, my gas water heater is located inside conditioned space. If only I had a part in designing my home, I would surely locate the gas water heater in a dedicated closet in the garage.

594tough:
I like the idea of a direct vent gas water heater. If only they had a cost efficient design.

How is your home heated?

Is it possible for you to insulate the door and walls inside your utility closet and pipe in outside air? This is the best I can offer.

You could do an energy equivalency study if you knew how much hot water you used. You could figure about 1/3 to 1/2 of your total water consumption during a month when you didn't use any water outside for car washing, swimming pool, irrigation or the like. Figure the cost of the gas by using the formula that it requires 8 BTUs to raise the temperature of a gallon of water 1 degree F. Subtract the temperature of the incoming water from the temperature of the water coming out of the heater for the temperature rise. Assume the gas water heater to be about 60% efficient. An electric water heater would use a 100% efficiency rating and one kilowatt of electricity is about 3,400 BTUs.

Who:
My home has gas forced air heating with direct venting (rated 92.1% efficiency) located in the crawl space. No air vent like that of the water heater that allows cold air to enter the home.

Furd:
Yes, it is possible to insulate the closet where the gas water heater is located. This could be a good move for some. However, this would reduce the size of an already small closet and I would have to apply weather stripping, and air tight sill, on the door. This is much more work than I desire. The truth be known, I prefer electric water heaters and I have an opportunity to get rid of the gas water heater that is currently in place. Still, I do not want to make the change to electric if the price difference in overall energy cost will be dramatic. That is why I originally asked if the overall cost of going to electric, and eliminating the awful cold air vent for a gas system, would be cost effective.

Simply put, I don’t think the cost to operate an electric water heater is as great as most would think when the water heater is located inside the living envelope.

Pizzazz, I was just wondering if you had a boiler. Then you could use an indirect fired water heater and not need any venting for it. You could replace your furnace with a boiler and air handler but that would be silly from a payback viewpoint.

The affects of the outside air requirements are a legitamite concern. This type of setup allows the flue to become a heat sink - heat rises out of it and is easily replaced by cooler outside air. If you make the water heater use strictly inside air, then you end up pulling cold air in through your walls and insulation. Pulling in cooler air through insulated walls can cause moisture to accumulate in the insulation and reduce its effectiveness. I think the key thing for any combustion device is to get its air piped in directly from outside.

An easily affordable reliable low emmission high efficiency direct vented gas fired water seems to be just a dream for now.

My electric bills average around $25 to $30 a month. My gas bill for the summer months probably average $20 a month although that includes a customer service fee, cost of gas and a transport fee. I have no doubt (from previously living with an electric water heater) that my electric bill would be quite a bit more than $25 dollars a month higher if I had an electric water heater in this house.

My electricity rate is one of the highest in in Washington state (due to the Enron fiasco) but it is still lower than many places in the US. Gas rates are on average higher than for the US as a whole.

As an energy systems engineer (retired) it really galls me that my water heater operates at no more than a 60% energy efficiency but in terms of economic return it is still a better deal than would be an electric heater.

Good god man, $25-30? Do you live alone in a 1 room shack? :)

Mine averages $240 a month, and that's with a gas stove. I'd dropped my electric dryer and electric water heater in a heartbeat for gas fired ones, either of them use more power than my 4 ton A/C does.

Yes, I live alone and no, I do not live in a one-room shack. My home is 1,550 square feet on one level. My electricity is billed every other month and my bill (including taxes) is usually between fifty and sixty dollars. I often have my television and a video recorder running while I am in a different room with the computer. I have three outside lights with either 9 or 13 watt CFL bulbs that run dusk to dawn and two 4 watt flourescents that run when I go to bed in case I need to get up for nature calls.

Otherwise I rarely have lights on except when I actually need them on. I have an electric kitchen range and I usually use a tabletop toaster oven along with a microwave oven to cook my meals. My refrigerator is not particularly energy efficient.

I have only a 12,000BTU portable air conditioner for cooling and so far this year I think I have used it a total of maybe 6 hours. The last few days have been a bit warm but my house inside temperature has not risen above 75 and that was late enough that merely opening the windows provided relief.