I have a rental property that I have been renovating for quite some time now and in the basement there are plans for a new kitchen and full bathroom. The bathroom and kitchen are to be directly adjacent to one another.

I want to have a separate or point of use water heating system to service the basement. I am leaning towards a tankless unit. I discussed the situation with a few local servicemen and I have received varying info.

All of them have suggested a unit with a flow rate capacity in the 4 to 5 GPM range. However some have suggested that I go with an electric powered unit, mainly b/c of a “flow control” feature that supposedly modulates the varying incoming flow rate in order to ensure an accurate out put temperature.

However others have suggested I go with a natural gas powered unit b/c of the additional efficiency and the fact that natural gas is available.

The “flow control” feature described to me seems very fitting for the type of application, and only a few electrical additions will be required since the basement was remodeled with a separate 200 amp circuit panel. But efficiency and comfort are one of the main selling points I wish to use when renting the property in the future, so I don’t want to rule out a gas powered tankless unit for the basement.

My question(s) is;

Does anyone know if gas powered models come equipped with similar “flow control” features? Or is this type of flow rate and/or power supply modulation unattainable with gas powered units?

When I have asked I received several confusing answers from several pros.

I've never seen a tankless gas water heater that doesn't modulate the gas flow to account for different water flows. How wide the range is another question.

You'll be fine with a gas unit, dont go electric if you have the option.

Hey thanks guys for the response,

Jonr if I'm not mistaken i do recall all the plumbers telling me that there are 2 types of tankless units; those that are "full on or full off" (I think those are the words they used) and "modulating units...

Is they're info somewhat out dated in your estimation? I have just heard so many horror stories with tankless and it's usually b/c someone has listened too much to the sales talk regarding this technology. I wanna ensure that if I select a gas model that the unit has the capability to account for alternating incoming flow rates and/or differences in incoming water temps.

Sounds right - I'd avoid any non-modulating tankless heater.

I've used tank and tankless water heaters - which is better depends on space, energy costs, are you using a recirculation system (for instant hot water), if you need very low or high flows, gallons used, price. If there is doubt about requirements - I'd lean towards a tank heater.

good point one of them did mention the option of using a tank along with a rec system instead. He said that the rec systems are not really compatible with tankless...

Sounds right - I'd avoid any non-modulating tankless heater.

I figured as much, well now nthat I know such gas models exist, how do I go about identifying them? It seems with electric models the manufactures often specify whether the unit is "Flow Controled" or "Thermostatic" but when I looked offline and online for a gas model, no such verbage.