What can you tell me about (electric) hot water heaters? I have a single family home with 2.5 baths. Do I want 40 gal or 50 gal? Are these things glass lined, by any chance, or is that an expensive option? Is it even necessary?
What else should I know?
In hot water…w/o hot water!
Buying a hot water heater?
What on earth for? Hot water doesn’t need to be heated.
I knew someone would pick up on this…
Actually, using Qdot = mCpdT, and judging by the wall thickness of the vessel, we find that there is a certain amount of energy lost across the walls, at so many BTUH that must be replaced depending on the k-factor of the wall and its thickness, t, and the temperature difference, dT, across the wall…
Well, in theory, anyway! 
I’m pretty sure they’re all lined with glass.
I’d buy the 50 gallon one with 2.5 baths, but it really depends on how many people you have using them.
We run out of hot water quite enough with a family of 4 (with a gas water heater) I’m getting a huge one when this one goes.
I do know that electric water heaters take longer to heat cold water than gas ones.
I found that the dimensions of the old one kind of dictated the dimensions of the new. I was hoping on putting in a 50gal tank, imagining my whole family taking luxurious long showers, one right after the other, and then was sadly let down when the fellow at the store checked out the dimensions and told me the bigger one wouldn’t fit in my space.
It died in June, by the way, a fact for which I am grateful. Two weeks of cold showers was not a big issue in June.
If you’re doing without hot water and you want to get a new heater in fast, possibly the best thing you can do is get to your nearby Home Depot and get them to hook up the hook-up. They schedule plumbers all day. I’ve got three water heaters to worry about, and when any of them has broken down, I’ve been able to get it replaced within eight hours of paying for the new one. It might cost a few bucks more to do it this way (I’m sure HD must mark up the plumber’s fee), but to me it’s been worth it. (If, in the unlikely event that you have no nearby HD, I’m sure that you can get similar service from Lowe’s or whoever.)
A forty-gallon tank seems to be more than adequate for the needs of two people, but if you have a bigger household than that, or just want to live large, go for the fifty, as long as it’ll fit.
In one of Consumer Reports better studies, they concluded -and I concur- that you should look for the water heater that comes with or offers the longer warranty. These heater had thicker walls, more corrosion resistance and were noticably improved over the cheaper models (or models with shorter warranties) made by the same manufacturer.
Nothing was a stronger indicator of durability than just looking over the warranties. Longer warranty = better product (and they cut these puppies open to substantiate)
Article was Consumer Reports Feb 2005 issue.
Good idea to measure the area where the heater will be installed, because they come in “short” and “tall” styles and you do not want to get one that will not fit, or to get a tall that would cause the vent pipe to need to go downhill.
The Consumer Reports discovery that (save one brand) better warranty = better innards was a surprise to me. I had heard that the higher price of the better warranty just represented the manufacturers increased risk of making a free replacement.
We found this fairly helpful when we were looking for a water heater.
I would go with the 50 gal. If you buy too small your only chance is the raise the water temp, which would lead to shorter life (the tank, not you personally), and higher energy costs (higher temp = more loss).