Does a tankless water heater make sense for me?

**matwags** · 02-21-2012, 12:22 PM

Brand new to the forum. I would like to ask for some insight.

I am currently fixing up a summer cottage on Lake Erie that I bought in the fall. The water lines in the community are shut off from Nov 1 to mid March in the community. It will be used almost exclusively between April and October. There may be a time in the future where the community keeps the water on full time. I could see myself or family members using the cottage 80-100 days a year.

Specs: Size-700 sq ft.
1 Bathroom with shower, but there is an additional outdoor shower.
Utilities- Liquid propane furnace and 80 gal hot water heater (both 19 years old). 100 amp service.

I will be remodeling the punched out utility closet due to wall cracks and water drainage issues. I would like to get rid of the chimney(which vents the furnace and hot water tank) which is at the bottom of a valley in the roof and put in gutters to improve drainage.

When discussing my options with a contractor, he suggested going to a tankless system and venting through the wall. Then, we could get rid of the chimney. Because electricity is expensive in that area and I currently have propane to the house he suggested propane.

The hotwater tank is 19 years old but appears to function normally. Does it make sense for me to go to a tankless system?

If so, any advice for BTU or temperature increase (I do not know the temp of water coming into the cottage)?

Any brands that I should look at or stay away from?

Thanks in advance,

Matt

**Dana** · 02-21-2012, 01:02 PM

Since it's primarily a summertime use situation, the odds are the incoming water will usually be at or above the deep-well water temperatures, so 48-50F seems likely:

If you have just one shower load at time even a ~100KBTU/hr unit would do, but a ~140KBTU/hr Takagi TK-Jr or Rinnai RV53P or similar would be enough tankless for 2 simultaneous summertime showers (I'm assuming you won't be showering outdoors in April very often...)

Brand wise- it's better to go with whatever has more local support & installer expertise. The big 3 would be Noritz, Rinnai, and Takagi which combined probably take more than half the US tankless market(?). Rinnai is the world's largest manufacturer of gas-fired appliances, and have pretty good north American support. Noritz has some of the nicest units in terms of tight temperature control at low flow. Takagi is a solid "value" version with reasonable reliability & support, and for similar size & features usually (but not always) comes in a few hundred below the others on installed price.

What you gain with a tankless is several square feet of floor area, but you get to put up with a few quirks as well. The "cold water sandwich" is the slug of unheated water that made it through the tankless during the delayed ignition cycle, putting a bit of cool or tepid water in the pipe between more fully-heated sections. Some find it pretty annoying, but that's more of an issue in the cold-water months in colder climates than yours.

Navien has pretty good specs at very attractive prices, but (apparently) not as tight quality control and (apparently) even less control over the expertise of the installers. I know people who have used them problem-free for years, but if forum posts and complaints about spotty support are any indicator, unless your installer swears to stand by it you may want to look elsewhere.

With any tankless be sure to have it installed with ports and isolating ball valves on both the cold and hot sides to be able to drain it for the winter (for freeze-control on the heat exchanger), and to descale it if it starts to lime up (a common problem in hard-water areas.)