'In Line' water heaters??

[Mountaineer]

Anyone have this? My little house it going to be really tight to find a location for a water heater. The designer is suggesting these.
Any idea on efficiency compared to a tank?
Price compared to tank?
It's for 1-2 people.
Seems like a neat idea, but also seems a little outside the box which scares me. I'm looking for efficiency and value.
Thanks for any ideas.

[LisaInN.Idaho]

We have a Bosch Aquastar that heats with propane and is is wonderful. I'll never go back to a tank heater. Here are a couple of threads from a while back that might help:
Tankless Water Heaters verses Regular
Propane Refrigerators/ Tankless Water Heaters

[frazzlehead]

Check with a local plumber before you install if you are on well water - mine told me that the water in my area tends to damage the pipes badly, and the heaters need replacing in short order.

I have a similar system but with a little tank instead of a series of pipes - it's not a hot water tank, it heats the water as it is drawn through, but it's bigger than those on the wall types. Probably .. hmmm... 1/3 the size of a regular hot water tank. I have a pressure tank too, so together they fill up the spot under the stairs.

Mine works off the natural gas boiler, so I only have one 'heating appliance' (I have in floor heating and hot water all from the same widget).

It's nice never running out of hot water!

[Mountaineer]

Thanks both of you. The first link is vry interesting, will check the other out in the AM. Electric doesn't sound so good, and that was my plan. I'm in a geothermal hotspot and figured it efficient to actually hook into it- so I'd like to stear clear of gas. I'll look into that further- maybe they've worked out the bugs.

[perennial]

we have a geo thermal system if that's what you mean by geo thermal hot spot. It's big though.

[EasyDay]

We looked into them when re-doing our old house. Like you, it was a space issue. They were expensive, which we first thought was okay... it would pay for itself (yeah, like in 40 years, after you do the math!).

Then we were told that if we use well water, we'd need a such-and-such filter... which was another several hundred dollars. As frazzlehead pointed out, minerals and such in well water will ruin it in no time.

In the end, we said forget it.

[Maura]

We also have infloor radient heat. Instead of a water tank and a furnace, you only have a water tank.

[Hammer4]

Acidity or hardness of your water may be a consideration, a water softener can take care of the hardness for you, I'm not sure what you do about acidic water....

[LisaInN.Idaho]

Originally Posted by EasyDay

We looked into them when re-doing our old house. Like you, it was a space issue. They were expensive, which we first thought was okay... it would pay for itself (yeah, like in 40 years, after you do the math!).

Then we were told that if we use well water, we'd need a such-and-such filter... which was another several hundred dollars. As frazzlehead pointed out, minerals and such in well water will ruin it in no time.

In the end, we said forget it.

It depends on the well water though. We are aon a well and have no problems with it.
Here is a post from the second thread I posted about how long it takes to pay for itself:

"Trendy? No. Efficient? Yes

A 40 gallon hotwater (Whirlpool Flame Lock) tank uses 40K BTU/Hr assuming an efficiency rating in the range of 75% and a flow rate of 66 gallons per hour. A tankless water heater uses 235,000 BTU/hr assuming a an efficiency rating of 82% and a flow rate of 300 gallons per hour. This works out to 783 BTU's per gallon for the tankless water heater and 606 BTU's for the tank based heater. So, on first look, it appears that the tank water heater uses less btu's than a tankless. However, the tank based water heater has to keep the water hot all the time rather than just when it is being used. Let's assume a duty cycle of 5 mins every 2 hours for the tank based heater to keep the water hot, that works out to 5 mins X 24hours/2hrs x 1hr/60mins = 1 hr of heating per 24 hours to keep the water hot, so we add another 40,000 BTU's just to keep the water warm. Now, lets assume that the avg family uses 100 gallons of hot water daily. In that scenario, the family would use 60,600 BTUS for heating water plus 40,000BTUS to keep it hot for a tank water heater for a grand total of 100,600 BTUS daily. For a tankless water heater, it would be 100 gallons x 783 BTUS per gallon or 78300 BTUS per day with a tankless. So, in conclusion, the tankless would save this family 22,300 BTU's per day. Considering that propane has approximately 90,000 btus in a gallon, this equates to ~157 gallons of propane per year or (at an avg. cost of 1.60 per gallon) about $251. Which means that the tankless would pay for itself in ~3yrs. This analysis does not take into account the 10yr lifespan of a tank water heater vs the tankless and it does not take into account the cost of floor space for a tank water heater vs. hanging the tankless on a wall"

[Hip_Shot_Hanna]

We have a Rennai propane powered tankless water heater and it's wonderful.

BTW - this type of water heater isn't "new" except in the USA. They were using this type in Japan back in the 1950's! And they are quite common in Europe too.

We like ours, are glad we are not heating water 24/7. We also have a solar batch water heater that preheats the water before it gets to the tankless system, so we use less propane to heat the water to the desired temp at the moment.

[mtman]

do yourself a favor build a little closet type room outside to house your water heater

[Dubai Vol]

We had an electric in-line water heater in Germany. Worked fine. The instant load is high, but it only runs when you are actually using hot water, so the KWh it uses is no more than a regular heater, possibly even less. The key is to have it as close to the tap as possible. Best to have one for each hot water tap, or else have the taps backing onto the same wall so the run is only a couple of feet at most.

[citilivin]

We have recently installed a Takagi natural gas system. We experimented by running two showers, the dishwasher and clothes washer at the same time to test it. It works great! Only heats water as you need it. For those in areas where permits are needed, some building depts have been relunctant to approve them.