Originally Posted by djlnc (Post 2166482)

What do you mean by an "instant hot water heater"? A tankless heater? What do you want to accomplish?

Originally Posted by lawngilander (Post 2166751)

I currently have to run the water at the bathroom faucet for 30 sec. or more to get hot water. That’s a lot of wasted water. I could install a POU heater, but I’m not sure that would help. Was just curious if anyone else had done this.

Originally Posted by retiredguy123 (Post 2166770)

I am a little rusty, but here is the math. The wasted water is the cold water that is sitting in the underground pipe that needs to travel through the shower head before the hot water arrives. Assume the pipe size is 3/4 inches in diameter and the water heater is 50 feet from the shower.

Area of the pipe cross-section is "Pi x radius squared" or 3.14 x 0.375 inches x 0.375 inches = 0.4416 square inches.
Volume is 50 feet x 12 inches x 0.4416 = 265 cubic inches.
In gallons, that is 0.00433 cubic inches per gallon x 265 = 1.15 gallons of wasted water

I invite anyone to check my math.

Originally Posted by Rheinl271 (Post 2166983)

The tankless heaters are two stage based on flow demand. With just the shower running likely with flow restrictor it will take two minutes at least to get hot. Heater runs on low output. If you run two faucets in the bathroom, the heater kicks in to high output and you get hot water in 30-40 seconds. Plumber explained how it works.

Originally Posted by keepsake (Post 2166885)

Just saw this ...
https://images.thdstatic.com/catalog...742ddd315a.pdf
120 volt 12 amp 1440 watt
Home Depot $199
4 tank sizes

Originally Posted by retiredguy123 (Post 2166994)

Note that, even if you just have the regular tank type water heater, you can reduce the time to get hot water by more than half by just turning on a hot water faucet and the shower at the same time. It greatly increases the flow rate to the bathroom.

Originally Posted by lawngilander (Post 2166338)

Would like to install an instant hot water heater on my small (1150 sq. ft.) Patio Villa. Have you done this?
What were your results. Also considering a POU water heater.

Originally Posted by Battlebasset (Post 2166346)

Our home came with one. Our shower is located at the most remote point from the heater. We run a solid two gallons before the water is hot enough to step into. It does save room in your garage as it mounts on the outside of your house.

We have learned to start the dishwasher or washing machine to clear the cold water in the pipes and "wake up" the tankless heater. We catch the first two gallons in a five gallon bucket and use it to flush toilets and water plants/grass.

Overall, I'm OK with it, but it's a bit annoying. I was always amazed when someone up north got one. I thought "that is going to take forever to warm up".

Also, you will need to set at least at 130 degrees. At the standard 125 the water will be too cold by the time it reaches you most remote point in your house.