Replies

1. 
   Brutag | Oct 12, 2005 09:41pm | #1

   I've had a gas tankless (Bosch aquastar) in my house for 3 years now and love it. 

   One issue I ran into initially was that the shower water temp wouldn't stay consistent.  Spoke w/ the dealer where I bought it and they told me it was known issue w/ older mixing vavles (this one was era 1940's).  Replaced it with a modern mixing valve and it's worked like a charm ever since.

   Other nice thing is that you can free up room in your house.  Depending on local conditions and codes, these can also be installed on the outside of your house. 

   Best part is you never run out of hot water....even when in-laws staying with you take 45 minute showers ;-)

    

1. 
   experienced | Oct 13, 2005 04:42am | #5

   Best part is you never run out of hot water....even when in-laws staying with you take 45 minute showers ;-)

   Isn't the purpose of the instantaneous water heater to save energy????

1. 
   Brutag | Oct 13, 2005 06:02am | #7

   Hmm, perhaps it would be better to run out of hot water when the inlaws are here ;-)

   seriously thought, a good solution for instantaneous hot water is to use a system like Tim described above.  Use either a boiler/tank combo and/or a traditional water tank combined with a recirculating pump is a great way to go.  That way pipes are always full of the hot water.

   Tankless sytems do save energy because they are an on-demand system.  They only heat water when you're using it. 

   I don't think any system is nirvana.  it all depends on what your goals are and what circumstances are presented to you when deciding. 

   Theoretical example.  Let's say you have a weekend vacation house.  Tankless might be a great option so that when you're not there, you aren't running any utilities at all.  Yet you don't have to wait for a tank to heat up.

   In my house, a tankless heater was the best decision at the time (and still is). Biggest factor was that I got the tank as a "scratch and dent" sale.  It's actually a takagi marketed under the bosch name and works great.   But in my next house I'd definately consider a recirculating hot water system.  It is very nice to turn on the faucet and have instant hot water.

    

2. 
   Tim | Oct 12, 2005 10:15pm | #2

   On the other hand, I had a Bosch AquaStar in my house for three years before I replaced it with a good 50 gallon tank unit and a bronze recirculation pump. The AquaStar is now relegated to heating the concrete slab of my garage floor. In the house as the sole source of domestic hot water, I hated it. It is suprisingly well suited as a small infloor heat source.

3. 
   jgealy | Oct 12, 2005 10:35pm | #3

   depends on where in the USA you're at, what your electric vs propane/NG costs are, what you want to heat, what volume of hot water you need, and where you want to put the heater. If you are talking small volumes of water like in a bathroom sink at the far end of the house that doesn't get much use, an under-counter electric instant water heater will be cheaper since you don't have to do a lot of plumbing labor and don't need to install a class III vent. In this case, the cost of the device plus installation will be far less than with a gas-fired instant HWH.

   If you need any significant volume of water you would have to consider a gas-fired unit. Be aware that installation costs of plumbing plus especially the vent (you typically can't use the vent from an old standard tank-type HWH) can get pricey.

4. 
   WayneL5 | Oct 13, 2005 01:16am | #4

   There's hours of reading on this in the archives.

5. 
   averagejoe | Oct 13, 2005 05:59am | #6

   What's your main space heating source? If you have radiant heat of some kind and so are using a high efficiency boiler, your best bet may be an indirect fired storage tank. They are extremely efficient and may offer better capacity than most tankless models if you need to run 2 showers at once or similiar.