Point of use/on demand hot water heaters

[Stimw]

Here is a pic of mine.
Too bad the supply line is on the wrong side.
I coulda mounted it facing the wall or upside down.

 

[Sodo]

If a tank water heater is within the heated envelope of the house, all the heat that "leaks" while you are "maintaining unused hot water" simply goes to heat the house, and your other heat source "runs an equivalent amount less". For example if the heater is in a closet, inside the house.

Forgot to mention the flipside, (cuz it's winter now). If your house is air conditioned, then you have to pay even more for your airconditioner to remove that "waste heat" that your tank heater leaked into the house. So you paid for the heat, once, then paid about 2x as much to remove it with the airconditioner, (totaling 3x). Thats when a tank-type water heater can get "expensive" to operate.

 

[downsizingnow48]

Since you are asking about electric, be sure to run your numbers comparing what the cost savings would be compared to having a small traditional energy efficient tank heater. In every case that I've run the numbers, there is no savings with electric on demand water heaters compared to the cost of the unit and how long it should last before being replaced.

I think that is right. In the Virginia house I switched to the on demand unit to save space in a 30x64 utility space that had the hot water tank and a washer. With the hot water tank out of the way up on the wall, I was able to install a dryer. I did some calculations, to the best I could tell there was no clear savings on costs maybe the reverse.

I installed a small hot water tank for the sink in my shop here in California rather than an on demand unit. Lower initial cost, simpler installation, and I only turn it on when I need it.

 

[EddieWalker]

Not on this topic, but I've also found that people with natural gas to their houses have to realize that the size of their gas line decides how big of a unit they can have. A lot of my clients don't have big enough gas lines into their homes, and the suppliers have said that the smaller units wont be able to keep up with demand.

 

[pmsmechanic]

Seems to me that if your not going to use this very often then a coil of stainless tubing with a propane torch stuck into it would do the job. Just light the torch and adjust the water flow to control temperature. My brothers use a setup like this for hunting. I don't see why it wouldn't work in a shop.

 

[Gary Fowler]

I know its off-topic but I've been using this on-demand propane heater at my cabin for 2 years. It's perfect for a shop too. Its 75,000 BTU and has no problem with my incoming water temp 40*F. 75,000 is enough for a shower, we don't mix with the cold (single pipe), and don't run it full blast, its too hot for that. $210, uses gas from a 20lb tank, and no electricity. A wild guess is a 20 lb tank will give 20 good long showers. It uses two Dcells for ignition and its had the same batteries for 2 years. .

Eccotemp L10 Portable Outdoor Tankless Water Heater Eccotemp L1 Portable Outdoor Tankless Water Heater - - Amazon.com

Its pressure activated. You just open the water valve and the flame starts. And you will be a hero if you bring it to Hunting camp.

That is what I was going to suggest. We had one in a Condo apartment in Peru-2 D cell batteries to start the flame. We had 2 of the 100 lb propane cylinders and with just the wife and I, one cylinder lasted about 4 months. It gave all the hot water we needed.

The biggest problem with the 220v electrical types is having the nearly 150(IIRC) amps available to power them. The wiring cost alone is enough to discourage their use. Propane supplied power is the way to go either with a tank type or instant hot tankless. The tankless type that uses 2 D cell batteries for ignition can be put anywhere and requires only the propane, no electrical power.

 

[TnAndy]

Just a sink in the shop is what I have, and I found a bronze, 2gal tank, AO Smith, 120v undercounter unit that works well for me. I wired it into a switch so I can cut it off when I'm not in the shop for a while. Plenty of hot water to wash your hands or wash out a paint brush/etc.

 

[MrWhippy]

One thing not mentioned here:

It is quite possible to run 2 on demand units in series to deliver the quantity and temperature of water if a single unit is not enough.

 

[Budweiser John]

Just a sink in the shop is what I have, and I found a bronze, 2gal tank, AO Smith, 120v undercounter unit that works well for me. I wired it into a switch so I can cut it off when I'm not in the shop for a while. Plenty of hot water to wash your hands or wash out a paint brush/etc.

I've thought about that concept also. Go to the shop turn on the air compressor and hot water reverse the process when leaving.
How long from a cold start until warm? What's the amperage draw at 110V?

 

[polkwrangler]

when my house was built in 08 I had a titan tankless water heater installed love it and never no issue.2400 square foot living area house electric bill 120.00 month