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Old 02-29-16, 07:09 AM   #2
stevehull
Steve Hull
 
Join Date: Dec 2012
Location: hilly, tree covered Arcadia, OK USA
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Flavin,

Bon jour and welcome to the site! I have put in tankless water heaters in all my homes and it really is not bad at all. They come in natural gas fired and also electric.

Each has advantages and disadvantages, but they are simple to put in and not difficult. They have advantages of both efficiency and long life. And most countries give tax rebates for putting them in.

Most gas units need an ac 120 V power line (I believe the Bosch types use "D" size 1.5 v batteries), a gas line sized appropriately for the BTU output and a vent. Garage install is a snap as you don't need input make up air.

Do not think that bigger is better. The large units require a larger volume flow of water to kick on the heater. For example, the Tagaki brand has a 90,000 BTU (90 kBTU) unit that takes less than half a liter (quart) per minute to turn on the gas valve. But the larger kBTU units require more volume flow to kick on. For this reason, you can't trickle water out and have it warm.

You also need to size your unit in terms of water rise and water flow. For example, in Florida the cold water out of the ground is already about 70 F (20 C). A temp rise to 110 F (45 C) is easy to get and does not require a lot of gas (or electricity).

But your water is COLD - about 40 F ~ 5-6 C. It takes a LOT more fuel to get the temp up for home use.

There is a trade off: water flow vs water temp rise. You can use a small tankless water heater (say, 70 kBTU) on your cold water if you only need 4 liters (quarts) per minute of hot water. But most house hold use needs at least double to triple that in terms of volume flow per minute.

This larger amount prevents the infamous shower effect where one person is enjoying a nice warm shower and another unknowing person starts the dishwasher (or maybe knowing . . . ) . The reaction/words of the person in the shower are always interesting.

So let us know if it is gas or electric. A lot of us here have done one or the other - I have done both.

Steve
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