tankless/ instant water heaters

sdnapier · #21 01/20/14, 12:25 PM

Quote:

Originally Posted by Tango

Ive had two; Bosch Aquastar which was propane and whole house. Now I have a Rheem electric unit for point of use but it is used for the whole tiny cabin: shower and bathroom and kitchen sinks. It works wonderfully. I love it. My model is 15 kw and measures like 12 " x 8 " with a tiny 4" depth, like the size of a cereal box. That was the reason I got it- the space is so small. Yes it does use 40 amps but it isn't on all the time. A shower takes like 5 minutes or less. Dishes take a few minutes. Handwashing under a minute. When I had a guest this past Christmas we never ran out of hot water. I'm sure we would have run out of hot water with a small conventional water heater that would fit in that space (space was the deciding factor). Also because my cabin doesn't have central heating, just a small space heater,the bathroom is often cooler than the rest of the cabin. I wonder if that would have meant the boiler on a tank heater would have worked more to keep the water at a reasonable temp.
My plumber explained the hard water problems and had suggested a prefilter and a backwash or something like that. I don't remember because I didn't get it but if you have hard water, it doesn't necessarily mean you can't have a tankless. You can add the maintenance options to protect the appliance. With the cost of propane, I'm not sure the propane models offer any savings over electric. I got mine off of Ebya brand new form an appliance company for $274 no shipping and no tax. There was really no competition. Best wishes

I'd love to see pictures of your tiny home and orchard. Have you posted them and I missed it? Sheryl

bluemoonluck · #22 01/20/14, 12:35 PM

We had a whole-house tankless hot water heater in one of the houses we lived in. I loved it! You could set the temperature of the water that you wanted, and adjust it instantly. And the hot water got up to my shower on the second floor (from the unit in the basement) just as quickly as it did from the hot water heater we'd had in there previously.

We had regular city water, not hard water. I'd put one in again in a heartbeat!

Tabitha · #23 01/20/14, 03:05 PM

WE have a Bosch Aqua star. Due to it's location it takes a while for the hot water to come. If we had a tank heater in the same place, it would not be any faster.
I like it.
My mother lives in an old stone house that never had hot water, she has a small unit under the sink and it works just fine. Nice to have unlimited hot water in the kitchen. It runs a tad slower. Mom's is electric.

**highlands** · #24 01/20/14, 04:55 PM

Quote:

Originally Posted by Rectifier

For the average family, a tank is actually more efficient. The cost of keeping the water warm is balanced out by the greater efficiency of the fire tube boiler. Add on top of that the tremendous cost differential between the units, and the fact that hard water will destroy a tankless in no time, and the old fashioned tank looks good fast.

The only really great use for the tankless is if you need a large supply of continuous hot water. Something like washing down dairy equipment. Even then, it's hard to justify the massive tankless unit required over simply a large tank.

Since I haven't actually used our new system for a year to get real data I won't call you wrong but that is nearly the opposite of what the propane company says, what the electric company says and what I've read everywhere else.

I've been researching this a lot because I'm in the market for two water heaters to bring water up to 145°F and to 185°F (USDA processing). We'll be catching the heat off our refrigeration in a heat exchanger tank from the condenser to act as a preheater and then boosting it with two propane tankless hot water heaters.

We'll see in a year.

Rectifier · #25 01/20/14, 08:33 PM

Highlands, I'm being a little unfair (or is it more fair?) as I'm comparing an expensive direct-vented condensing tankless heater to an expensive direct-vented condensing boiler type storage tank. In which case, the condensing boiler, being fire tube, is both more efficient and better at handling surge loads, like showers, baths, laundry etc.

You can also dump other forms of heat into a tank easier, such as solar thermal, extra capacity from solar/wind, bale burners, wood stoves...

I will concede the point that the average tankless will consume less fuel than the average hot water tank. However I believe the simplicity, low cost, and durability of the tank bring the total cost of ownership far lower for the tank. I am currently designing a hydronic system for my farmhouse centred around a pair of conventional natural gas tanks - this system will run when the power is out (with a battery backup circulator pump) and you can't say that for very many heating systems these days.

In your application, using preheated water and doing large volume processing, you can afford the up-front expense of a powerful tankless system - and I agree that it's the best system for you - but it's a bit different from the average household usage.

Kasota · #26 01/20/14, 09:04 PM

Another factor to consider is what temperature rise you need. I get my water from Lake Superior and even in summer that water is way colder than the well water I used to have when I lived in central MN. You can run the kitchen tap for a wee bit and the water is like it came out of the fridge.

One person I know who went tankless actually a water tank (I think it was a non-functional water heater) in the basement to hold water that would then go to the heater prior the shower. This set up meant that the temperature rise was much less than it otherwise would have been because their basement was heated (usually kept at around 65).

Not sure if that helps you any.

Fae · #27 01/20/14, 09:13 PM

I have never had a point of use water heater but I do have a whole house tankless propane and I love it. It is so nice having a shower and not running out of hot water. My propane usage has gone way down also.

citilivin · #28 01/20/14, 11:43 PM

What is important is to choose the correct model to meet your needs. Secondly, have a filter installed for hard water. We have a Takagi and it more than meets our needs for five people. We installed a recirculating pump and we get hat water instantly. This is our second system because the first was installed about ten years ago, before the affect of hard water was known. I highly recommend on-demand systems.

Tango · #29 01/21/14, 05:09 AM

Quote:

Originally Posted by sdnapier

I'd love to see pictures of your tiny home and orchard. Have you posted them and I missed it? Sheryl

Howdy, thanks for asking. I don't have a tiny orchard yet. I've 3 trees planted: pear, peach and plum and 11 more on the way to be planted this week when they get here. My goal is to plant in a garden forest fashion with clusters that include nitrogen fixers and insect repellers. Progress will be kept on my blog. This is just the beginning

I do have photos of my tiny cabin up on the For Sale forum under Tiny Cabin on 10.3 acres in mid Tennessee or something very similar to that heading .... long story

ronbre · #30 01/21/14, 10:47 AM

we have pex with hot water to two heat exchangers in our house from our outdoor wood furnace (son has 4 at his house from same furnace)..

one of mine is for heat blown off of our furnace heat exchanger thru the ductwork (we have propane for back up )..the other heats our water (we have propane water heater for backup)..I love it

NorthwoodsMike · #31 01/21/14, 01:30 PM

Quote:

Originally Posted by ronbre

we have pex with hot water to two heat exchangers in our house from our outdoor wood furnace (son has 4 at his house from same furnace)..

one of mine is for heat blown off of our furnace heat exchanger thru the ductwork (we have propane for back up )..the other heats our water (we have propane water heater for backup)..I love it

On the hot water heat exchanger, do you have a circulator, or does it just pass through the exchanger once as it fills the tank?

I may be looking at a similar setup in the future.

Sorry OP for the sidebar.