"Will an instantaneous water heater save me money on my utility bills?"
Yes, in most applications you will see a savings. There are some variables that could reduce the amount you save. One example is you will not run out of hot water, so longer showers could cut into your savings. Also, the cost of electricity, propane and natural gas in your area will affect the amount of money saved. The higher the cost for the energy type used to heat your water, the quicker you will recover the higher initial cost of installing a tankless versus tank style water heater.

Positives:

You will never run out of hot water. "You want an hour long shower? No problem!"
Electric units can be installed at the point of use.
You're not paying energy costs to heat water 24 hours a day.
They're easy to install.
Our electric units don't require a T&P valve. (No tank!)
Installing a tankless water heater will indeed be a bonus to the environment (why should we choose wastefulness when we're talking about finite natural resources)?

Negatives:

They all need a minimum flow rate & pressure to turn on.
The faster water flows through them, the lower the temperature rise. So,if you expect to take a shower while the clothes washer is running, you will need to select a unit sized to your hot water flow requirements. (Gas units handle this a little better than electric models)
Electric units need heavy gauge wire. Example: the 9.5kw must have 8ga wire and a 50amp breaker.
Gas units need a much larger, special flue pipe and larger gas supply than a conventional water heater.
At times they can produce very hot water. It's easier to get scalded.
Gas units are more complicated than a conventional water heater.
With some brands, parts are hard to find (not a negative if you originally purchase from us, as we like to carry parts for the units that we sell).

Summary:
Tankless water heaters have their place. They're not "the answer" to every hot water need, but if they're used correctly they can be the solution to many of them.

"If these units don't have a tank, how do they know when to turn on?"
The tankless water heaters have a flow switch built into them. When you turn on (open) the hot side of a faucet the water then moves (travels). Once the water is traveling at 3/4 of a gallon per minute or faster most tankless water heater switches will then turn on the gas or electricity.

"What's the difference between a conventional flue and a direct vent?"
A conventional flue is what most people are familiar with. It typically consists of a double-wall flue pipe going from the top of the heater through the roof, venting outside. The fixture draws its combustion air from the space around it (utility room, garage, hallway, etc.). A direct-vent unit on the other hand, both vents and draws its combustion air through a specially designed pipe from the outside via an adjacent wall.

"On the electric tankless models; why should I buy the thermostatic model instead of the lower priced flow model?"
The thermostatic model has a number of advantages. A non-thermostatically controlled model's outlet temperature is dependent on the flow rate, and it can create a potential problem with anti-scalding valves and the like. When in doubt, please order the thermostatically controlled models. Also, the thermostatic models can have a warm or hot water source, but the non thermostatically controlled models are only designed for a cold-water source/input.

"I would like to convert my natural gas tankless heater to be able to use LPG (propane) gas instead. Do you offer a conversion kit?"
Sorry, but we don't. Even if we could, we probably wouldn't, as in most cases it is not a good idea to convert one type of gas for another. Burners can be different, orifices, etc. Not only is the BTU rating different for these two gases, but also the heat of the flames and a number of other factors. We simply do not wish to sell ("profit from") something that might create a non-safe environment.

"Can I install tankless water heaters in my attic?"
Without seeing all of your plumbing piping, etc. it is difficult for us to answer with a straight "yes" or "no." One must be sure that a possible water siphoning condition can not be created as tankless water heaters should not have air in the lines. Water siphoning out of any brand of tankless water heater might damage the heater when there is no water (or not enough water) in the lines.

"Is it possible to drain a tankless water heater to prevent freeze damage when not in use?"
Yes on most brands (best to check first though with the supplier). Simply drain both lines 'to' and 'from' the unit. As long as there are no check valves in the way, that should drain the water from the unit. To guarantee that there is no water in the unit, we recommend two drain valves - one before and one after the unit - as well as blowing air through the water line.

"Your products specify the 'temp. rise' based on the GPM flow; what do you mean by this?"
Temperature rise is the amount the heater raises the temperature of the incoming water, based on the flow rate shown of that water.

"Can I replace my existing tank type water heater with a tankless water heater?"
Yes, but there are specific requirements that will need to be addressed. Gas units will require a larger, special vent pipe and a larger gas supply line that not only will supply the water heater, but all other appliances on that gas pipe run. Electric units will require larger gauge wire and breakers than most tank type water heaters.