Tankless water Heaters

Heaterguy

Tankless water heaters are far more efficient than tank water heaters, and you never run out of hot water.

Red Squirrel

I've been wondering about this. The concept makes sense. Only run when needed instead of storing the water and continuously keeping it hot.

What about gas vs electric? I like the idea of electric as it's more DIY friendly and better for the environment but I hear they have a pretty big power demand.

Heaterguy

it is true that the electric one's use a lot more electrcity. That's why we sell only natural gas or LPG. I had one electric I sold it but it was 220v. The guy liked it though.

Yoyizit

Who says so?

Heaterguy

Keeping water hot in a tank heater cost's about 20% of your electric bill. So by not having to constantly heat water you save a lot of money. You don't run out of hot water either. I have known about this technology for twenty years it is thw standard in Europe and many other parts of the world.

Yoyizit

My 70s elec. WH ran 5 min each 5 hrs. without an external insulation blanket. 75w out of 1 kw avg. usage is 7.5% and they are better insulated today.
How long to payback the cost of increasing the size of your resi. service to accommodate this thing?

In 4 weeks in Germany I never got the hang of avoiding cold water dumping on me at least part of the time in every shower I took. The thing can't anticipate usage.

Heaterguy

Ours anticipate usage. And I don't know where you get your figures at because I have a lot of positive feedback about energy usage. My own house is a testament to that. If you had a 70's heater it was know doubt an energy hog. I read in popular science that conventional water heaters use up to 20% or more of your energy bill. My brother found that out by buying a tank water heater.

pyper

I think the payback period is probably infinite. Ours cost around $1000 (including the purchase price) to put in. We had to have a new regulator put on the LP supply, run new line, and put in a new chimney.

The old (very old) water heater would run a 40,000 BTU burner for about 15 minutes after a shower to re-heat the water in the tank. The tankless runs a 250,000 btu burner for the length of the shower. The only other variable is the pilot light which ran 24/7 on the tank heater. The tankless has no pilot.

There was no noticeable difference in our gas usage before/after.

The tankless has a smaller footprint which made our new floorplan work, and it was worth it for that reason.

Heaterguy

Ours sell for $425. They should not be vented out the chimney but direct vent like a dryer by venting it out the roof you probably will shorten the life of the heater, because of condensation leaking back into the unit. I'm glad it worked for your floor plan. We also sell smaller models that you can hook up to a propane tank and take a warm shower while camping.

Yoyizit

I had an elec. WH that ran on 240v. I got an analog 120v clock and hooked it up to the 240v heater element through a dropping resistor to give me ~120v.

As is, with using no hot water, the heater ran 5 min. out of every 5 hrs (300 min) to offset heat loss through the insulation. This is 4500w(5/300) = 75w.

After I wrapped it with addt'l insulation it ran 5 min. out of every 7 hrs, giving 54w.

The tanks nowadays are probably better insulated.

The avg. US elec. usage is 1 kw, up to 4 kw, depending on where you are.
http://www.eia.doe.gov/emeu/consumpt...on_tables.html

Heaterguy

An electric tank water heater would cost more than any other. What about when it needs to heat water. You only talk about it when it's not using any hot water. Tankless water heaters are considered green and are the future. No matter what you think!

Yoyizit

I'll take two!

stuart45

My daughter has a combi boiler, and it's OK for a small house as it does away with the cold water storage tank in the loft and the hot water cylinder. However it can't cope with large amounts of hot water being used at the same time. They have been used here for quite a few years now, more as space savers. A traditional boiler heats the hot water in the tank through a heat exchanger off the central heating system, so this is more efficient than the combi. Also with a combi when it breaks down there is no backup of the electric heater. Nowadays we have to use a condensing boiler when replacing an old one. The problem with combi and condensing boilers is that they are more complex than the old ones and cost more to service and maintain.

Heaterguy

Yoyizit

75w x 8760 hrs/yr = 660 kwh/yr @ $0.15/kwh = $100/yr.

$1K invested at less than 7%/yr = less than $70/yr.

Payback on a tankless heater costing $1k is $1000/($100-[less than $70])/yr = less than 33 yrs.

How long did your water heater live? A 16 yr life for NG WHs seems to be average.