tankless water heater??

[excess11]

I am looking to save some money on the electric bill and was thinking about a tankless water heater (or also known as a instantanious water heater) for my house. I was looking at the whole house models. I have propane and electric available for fuel sources but I am leaning towards electric. What are your expierences with these units. Are they worth while?, Do they save money? Are some brands better than others. Things to look for or to avoid. I was looking at the Eemax series 3 heater. It is just me and the whife and it seems like a big energy sucker keeping 50 gallons of water hot all day long for the maybe 10 gallons of hot water used a day. Please give me your thoughts about this because I am not sure what to do!!

[81xsproject]

Just remember that w/ a 'tankless' water heater, when the power goes out, no hot water.

[BrianB]

I do not know that much about these but I do feel that a Propane tankless would heat quicker and better than an electric.

http://www.consumersearch.com/www/ho...water-heaters/

http://www.consumersearch.com/www/ho...s/reviews.html

http://www.nextag.com/tankless-water-heater/search-html

Lots of reading here!!!

[Ken Talbot]

SWMBO and I just installed a Takagi T-K3 propane fired tankless heater. This unit fires at 199,000 Btu/h, and will deliver 257 GPH or 4.3 GPM when raising the water temperature by 77 degrees F (from 58 degrees to 135 degrees) Output tepmperature can be set with dip switches from 104 to 185, or you can get a remote control to set to whatever you want at a particular time.

When you're looking at these units, you need to consider your input temperature, which here in Canada is considerably cooler in winter, and your desired output temperature. This tells you how much temperature rise you need. Then you add up a few appliances to see how much volume you might want at any time. For example, a bathtub will run approx 4 gpm by itself, while a lavatory faucet might only run 1 gpm. We actually held a bucket under each appliance in our house to see how much they ran. Temperature rise and volume desired will steer you to an appropriate model.

The electrician I had in to wire up the unit said he had been considering electric tankless for his older house, but figured that would mean running in a new 400 amp service to be able to provide enough juice. We already had a propane fired furnace and water heater, so for us, propane was the obvious choice.

We were faced with replacing our tank this year because it was just coming on 10 years old. Our insurance company told us two years ago that 10 years was the maximum insurable life on a conventional hot water tank. If we had a burst and water damage after the 10 year mark, we would be on our own for repair costs.

When you go shopping for a unit, and lining up a gasfitter and electrician for the installation, you want to be sitting down when it comes time to talk about price. Ours ended up a bit over $3000 installed. I figure that is pretty close to double what it would have cost to put in a new conventional propane fired tank, so I consider my payback amount to be $1500. We'll see how the bills work out over the next few months, but the first one was promising. Last year, our September gas consumption was 2.0 gigajoules for hot water alone as the furnace was not on until October. This year, with the furnace still off, our September consumption was 0.8 gigajoules. As they say here at the forum, YMMV.....

[fredintoon]

Hi Dan,
Instant water heaters are real popular in England because if you have an older house there it's the only way to take a shower instead of having a bath. (Older Brit houses run cold water straight off the water mains and hot water from a far lower pressure header tank in the attic) That said, whether you go with gas or with electric depends on the price+installation+maintenance+running costs of each where you happen to live, performance-wise, they are equal. One thing you might consider is having a separate system near each major hot water use point. Being in the upstairs bathroom wanting 2 minutes of hot water to wash your hands and waiting 5 minutes for the hot water to get there from the central unit in the kitchen and knowing that after you are done there will be 5 minutes worth of hot water left in the pipe uselessly cooling tends to negate the reason you installed the system in the first place.

[Crazcnuk]

The size you will need is very dependant on what the water temp coming out of your pipes is too.

The colder the water coming in, the bigger the unit you need.


Ah, good ol natural gas!

[excess11]

Gas=$$$

I was once a pipe fitter for a local propane company and do see advantages of gas,but the price of propane here is around $3.00 per gallon. This price tends to kill any advantages of gas. I do like propane it is a great source of heat,I just wish the propane companys were not so greedy. When I left the propane industry in 1998 the person that did their purchasing would not buy propane in bulk if it went over 34 cents per gallon.

[kf4anm]

flow

We considered a tankless in march when we took control of our new house. Our utility closet was desinged for a stack w/d sandwiched inbetween the furnace and hwh. I thought going with the tankless on the wall so I could fit our existing w/d in the space. I researched and was for the idea. It was explained to me to activate the burner to heat the water the flow had to be a certian pressure. so a trickle might not be enough to keep the water hot. Instead I went with a convential 40g energystar rated hwh and have been pleased. Of course I had to drop 900$ on a stack w/d but thats another story.

[excess11]

Heater spec's

Eemax EX280T2T Series Three Electric Tankless Water Heater Specifications:
• Dimensions 10.75" x 5.25" x 2.125"
• Weight 12 lbs
• Volts 240V
• KW 28.5kW
• Amps 120(3x40)A
• Rise at 2 GPM 96°F
• Rise at 3 GPM 65°F
• Rise at 4 GPM 47°F
• Wire Size AWG 8

Here are the specs it sounds like it should be more than enough!!

[Ken Talbot]

Here's a link to one of many sites listing selection criteria for tankless water heaters.

That particular unit would be quite a bit undersized for the conditions I wanted to fit, but it could well be okay for your needs. What sort of winter groundwater temperature, flow rate, and delivery temperature combination did you work with to come up with this unit?

[excess11]

Size??

I live in southern Pa. with public water. The incoming water would be in the 50-55 degree range. I have a 2 gallon per minute shower head so doing the math that would be 146 to 151 degree water. Even at 3 gallon per minute 115 to 120 degree. Sounds like more than enough for my planned use. Am I over looking something?. I would like to make sure this unit is large enough to be happy with its performance. What do you think??

[Ken Talbot]

With those numbers, you should be okay. Even if somebody was to run some hot water at another kitchen or bathroom sink while you're in the shower, you would probably still be okay, at least as long as they're not running a high-flow fixture like a washing machine or dishwasher.

[excess11]

GPM question

I have a question about the gallon per minute flow on these units. I seen where someone listed their tub filler at 4.3 gallons per minute. My question is when you fill your tub you usually do not fill it with only hot water. It is usually a blend of both hot and cold water. When I run water for a bath the valve is usually just a little bit past center to the hot side. I would guess like 70% hot to 30% cold water to fill the tub. So 70% hot water at 4.3 gallon per minute flow would be about 3 gallon per minute of actual hot water flow. Does this math seem correct. Even with a shower or sink you not use 100% hot water to wash your hands or shower. So I do not know how to use the gallon per minute formula when the total flow of most uses are not hot water only applications??

[Ken Talbot]

You are on the right track, Dan. To check this against your current system, start by measuring its temperature when it is running full hot. Then, start running the tub the way you normally would, and check the moderated temperature. Now, shut off the cold tap, and use the bucket/stopwatdh technique to see how much you're actually using. You might be surprised how little cold water it takes to moderate from full hot down to what you want for that nice tub soak. I did this same exercise for my shower. If you run a tankless system, or any other system for that matter, at the recommended 122 degrees, you need to run just about pure hot for a good shower or tub, and that still gives you only "medium" for the washing machine.

[Dragonrider]

On the electrics....be sure and check with your utility company...many electric utilities around the country are tacking on a surcharge for high "peak loads"...that is, the top wattage reached at any given moment...

A tankless is more efficient overall, but has a much higher peak load than a tank(ed) one.

So, check with your electric company and make sure they don't do this and aren't planning to (it's a new thing in residental service, but is expanding).