Yes, the cost is an issue. And as someone else pointed out the variables involved are a bit overwhelming.
1. I read a study that said that tankless water heaters in use are not saving energy at nearly the levels implied by the government tests, which assume long draws. In practice, homeowners are taking a lot of little draws to wash their hands or a dish, which are not efficiently handled by a tankless water heater. Might as well have a well insulated tank for these small draws.
2. Some tankless now actually have a small tank to overcome the problem of short draws and cold water sandwiches. But one study showed that these can be very inefficient unless implemented properly, so you lose any energy efficiency in having a tankless. Perhaps better to get an inexpensive gas tank model to handle this.
3. Do-it-all tankless units are very expensive, but cheaper units can be had (with some decent reviews). Wouldn't want to rely on smaller and cheaper for all my water needs but should be fine in combination with something else (eventually solar but not quite there yet).
4. There is energy a wastin' in my basement air, partly because of summertime heat and humidity and partly because I can link to a large and insulated crawl space area, which is probably 54 all year round (guessing on that temp).
5. Would be nice to dehumidify the basement (and crawl space) in the process of getting heat in the summer, but would not like to do as much of this in the winter. Seems inefficient to take heat out of the air to heat water and then pump in more heat to keep the basement warm. So would crank down the hpwh in the winter and rely more of the tankless.
Again, I am just guessing on lots of this stuff. Thanks for any expertise you can offer.
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