Instant Hot Water for Showering, an Energy Saver?

steamup wrote:I've installed two Navien units on different jobs. They are a 98 percent efficient unit, propane or natural gas fired. One heck of a unit but a little pricey. Vent with PVC. Attached is a picture with one used for hot water plus radiant heat for a small house.

Navien installed with radiant.JPG

That looks just like every Dutch house or apartment I've been in. Either underfloor radiant in the newer homes or those really nice slim panel radiators on the walls. The boilers sometimes are even installed in the attic, but can be anywhere (kitchen, bathroom, etc.). Nice.

Chris

4500 watts is what most electric water heaters use.The instant HWH are much higher!But you are right 6 or 4 ga. wire .10 or 12 ga. to normal water heaters

Sting,
Turn off the gas (and pilot) to your gas water heater tonight and see how warm your water is in the morning.I think you'll be surprised.That's just the standby loss over night.

I wondered if someone would doubt me?

The data I post was gathered off 10 new NG appliances on demonstration in a lab, each unique in brand. Standing pilot light, naturally vented, also insulated with an aftermarket blanket kit. They were gathered in a row, Plumbed in isolation to one another, each with an expansion tank and filled to city pressure. Each gas train was on a separate gas meter. They were brought up to code set temp - the meters were zeroed and they were left on set at 120 degrees for 30 days.

I only post the result of that test - as it was related to me.

I have no documentation - I have no web link to show my expertise - Maybe I just made it up! At best its second hand information.

So it becomes a --- Believe it or not thing! Your mileage may vary.

And yes I do turn off my NG heater at the farm every Sunday night - along with the well pump breaker-- only to turn that business back on the following Saturday -- If I draw from the left tap immediately upon arrival - the water isn't 120 degrees -- but its not well temp either. I guess after 6 days there should be some standby temperature loss

-- but lets review -- First hand information now.

the average DHW appliance just sitting there did use x therms of energy.. My NG bill at the cottage in the summer is only for DHW and the dryer, but that use - several loads of laundry and several long showers - a Large tub fill or two -- I still only use a few therms of NG, a week.

Ill stand by my statement. A Traditional DHW appliance just standing in the basement holding 40 gallons of DHW for immediate and hi demand use -- IS NOT and energy hog.

A dripping or always open left faucet is.