Friday, May 29, 2009

The Rheem RMGT 42PVN tankless water heater

This is a tankless water heater.  It retails for $764.99.  The way these work is that instead of heating water up and leaving the hot water in a tank, they blast the water up to working temperature right when you need it.  This is a tradeoff, of course.  If you want to take two showers while doing the laundry, you're going to have really tepid showers.  But the upside is that it's cheaper (because you heat water only when needed) and if you don't use too much water at once, you never run out of hot water.

So the water heater is shot in the carriage house, and wonder of wonders, I found an instance of this model of water heater on Craigslist, five blocks away, new in the box, for $250.  Of course, I bought it immediately.  I'll install it this week.  I can do the water part, but my dad will help with the gas pipe.  That's something I've never done -- metal pipes.  Or I might (gasp) call a plumber for the gas pipe.  I'll bet the gas company would be happier if I did that.

The only problem with putting this in the carriage house is that I want another one for the upstairs in the big house.  And that one will cost me regular price, and it will hurt to pay that much more.  (I had been resigned to it until now, you see.)


  1. We desperately want one of those, not so much to replace our current hot-water heater, but as an auxiliary unit. The bathrooms in our house are at the opposite end of the house from the utility room, and flushing the cold water thru the pipes (especially in the winter) is a lengthy and frustrating exercise. If we could use the main heater only for the kitchen and laundry, and have an on-demand heater supplying the bathrooms, it would probably save as much time as money.

  2. Well, you don't need 4.2 gallons per minute if you're just heating water for a shower. Shower heads sold after 1994 in the United States have a flow of no more than 2.5 GPM, and low-flow shower heads (which I hate) are even less. But you can easily get away with a smaller heater if you're just operating one bathroom -- or just one at a time.

    I don't actually need this one for the carriage house, of course. I may move it later, and get a smaller one for the carriage house, but for now, this is what I have, and I need hot water in the carriage house. And I'm putting the washer hookup there anyway, so ... might as well do it right.

    Note that if you buy a new natural gas tankless heater, you can get a 30% federal tax credit on purchase and installation right now. So definitely, if you're going to do it, do it this year or (probably) next.

  3. Look on eBay when you're not in such a hurry. My contractors found my two (forgotten brand) for less than full price, although not as low as $250!
    (I never read Open Threads until they've accumulated lots of comments, so I'm just catching up here.)

    Mary Anne in Kentucky