Under-Counter Tankless Water Heater ??

[zookeeper16]

A friend of mine mentioned that she saw an ad for this at Menards.

Anyone have any reviews or opinions on this item? I have never even heard of it, so I couldn't help her. Told her I'd ask on this board.

[cowboy joe]

I believe this is nothing more than an 'on demand' water heater which heats the water as it passes through. IMO, this is not very efficient if the main, traditional style water tank is in place as the main tank continues to consume resources. The better application is to replace the hot wate tank with either a tankless heater for the entire house or several small units scattered about.

[Shagbarkmtcatle]

It is an on demand water heater which is water heater that only heats the water as you use it. It is not practical in most applications as people do not have enough electricity or gas to operate a large one.
The under the sink works well for one-three fixtures. Say you have a hand sink in a work shop, it's practical there. But to run a whole house electric one, requires a tremondous power load and most houses do not have that.
I am putting one in my cabin where we only stay a few days out of the week and don't do laundry or have a dishwasher. So it will only be for the kitchen and bathroom sinks and taking a shower.

[booklover]

My in-laws in Turkey use this. Actually everyone uses the same system in Turkey (those that have hot water, that is). It efficiently heats on demand. We've never had problems with it when the 8 of us are all taking showers in the morning. You don't run out of hot water... and you're not heating water that has to been kept at a particular temp whether you are using it or not, so it seems MORE efficient to me. They have one for each water source that requires hot water.

[DAVID In Wisconsin]

Menard's sells two types. One is a gas powered on demand heater. It will supply enough hot water for any home.
They also carry a small, electric under the cabinet heater that generally heats tiny amounts of water, generally for one fixture. These are often used to boost water temps at a faucet far from the main house's water heater.

[Callieslamb]

they are great. Gas models are more efficient than electric. You don't have a tank of water sitting around waiting to leak. They are also good if you have a long run from waterheat to faucet to add as a source for hot water for the one faucet. Cost effective for one faucet? I am not sure. We put a big one in our house - we are taking it out so we can move it with us.

I am not sure that the ones sold at Menards or Lowe's are the best models. We found a gas one that we can light manually in case of a power outtage. I think it is a Bosch.

[MaineFarmMom]

We've had propane heated, on-demand hot water for 11 years. I have no intentions of going back to a tank. We've never run out of hot water. It has no problem heating our icy well water. It's very efficient.

[Keithb]

I'm sure your electric company wouldn't like it because of the instantaneous spike it causes on their system. Some of these units will peak at 20+kw and most residential transformers are 10kva or 15kva transformers for a typical home.

When we built our home 7 years ago, we purchase a Marathon electric water heater through the company I work for. It's pretty darn efficient and normally only runs twice/day.

If a traditional water heater has 2-3500w elements for every hour it's utilizing 7kwh. If an on demand is used at 20kw and typical hosuehold showers, baths and other misc. hot water use say is 1 hour, then that's 20kwh. I may be way off, but it doesn't seem logical to me.

240volt on demand at 120 amp circuit is 28.8kw so that's even more. I'm sure natural gas is different but our gas prices are somewhat more than electricity around here.

[cowboy joe]

The electric on demand units are not very expensive until you have to install the unit. The smallest unit I've seen needs a 40A breaker and requires 8 ga wire. 8 awg runs around $2.50 a foot in these parts.

[LisaInN.Idaho]

Originally Posted by MaineFarmMom

We've had propane heated, on-demand hot water for 11 years. I have no intentions of going back to a tank. We've never run out of hot water. It has no problem heating our icy well water. It's very efficient.

Ditto. We've had one for 6 years and the savings in propane is pretty significant versus the tank type water heater.

[unioncreek]

We have an under the counter hot water heater at work and it's about the most worthless thing. If you want hot water you can just turn the faucet on to a trickle for it to bee hot. If you get one make sure that it's plenty big enough.

Bobg

[Nevada]

Originally Posted by cowboy joe

I believe this is nothing more than an 'on demand' water heater which heats the water as it passes through. IMO, this is not very efficient if the main, traditional style water tank is in place as the main tank continues to consume resources. The better application is to replace the hot wate tank with either a tankless heater for the entire house or several small units scattered about.

To accomplish immediate hot water at the sink you wouldn't use a tankless water heater along with a traditional water heater, you would use a temperature activated valve like the Hot Water Lobster.

The idea is that there is a natural convection current created by the upward movement in a traditional water heater. You can take advantage of that current by opening a path from the hot water line to the cold water line. With the valve opened a small amount the water will naturally circulate from the hot to the cold water side, keeping the hot water line warm (maybe 90 or 100 degrees). The valve is adjustable to the desired temperature.

In my opinion, the Hot Water Lobster is grossly over priced at $180 + $20 shipping, but it does do what they claim it will do.

[highlands]

I spent a lot of time researching these. I like a lot of things about the concept but there are some problems. First, I'm not interested in the gas version, which would solve some of the issues but I don't trust gas/propane/lpg, etc.

The on-demand hot water heaters take up very little space. That's a big plus.

On the down side, they are not rated to raise the water temperature very much. We have very cold water. These units are designed for relatively warm ground water. The result is I wouldn't be able to get a good hot shower. One work around for this is to run several of the units in series. That gets expensive both in terms of electrical usage and in terms of multiple units.

Then there is the electrical usage. They use a lot of electricity when running. This requires special wiring and a large service to the house. Something else running at the same time could result in brownouts that can damage electrical motors like compressors in fridges and freezers, etc. For me this was a big stumbling block. We are very rural and have limited amperage coming into our house. To get higher amperage at the service panel means spending tens of thousands of dollars ($45,000 last quote). That makes it not feasible.

Lastly, the high power spike makes going off grid impossible. I can generate power with wind, solar and hydro. None of them can supply the instantaneous power needed by these units without extreme battery banks and inverters. Again it drives up the costs too much.

An advantage of a tanked water heater is it can be coupled with solar hot water and wood stove hot water. The hot water tank is inside the insulated envelope of our house so any heat lost is lost to our house which needs heating 10 months out of the year - we're in the mountains of northern Vermont where it rarely ever gets above the 70's. So I finally concluded to stick with tanks.

Cheers

-Walter
Sugar Mountain Farm
in the mountains of Vermont
http://SugarMtnFarm.com/blog/
http://HollyGraphicArt.com/
http://NoNAIS.org

[zookeeper16]

Thank you everyone for your responses. I gave her the link for her and her husband to read over.