residential domestic hot water

markootz

Can someone please tell me what is the most efficient way to heat residential domestic hot water? I'm looking to replace my gas fired 40 gallon hot water heater. Is indirect hot water heating more efficient or are there other ways or products? Iheat my house with a hot water boiler. Thank you for your responses.

Jackchips

You should get

many techical answers before this thread ends but the bottom line is having plenty of hot water when you need it. Gas water heaters are very efficient and they allow you to shut the boiler down during the offseason (if there is one). I believe there are better avenues for savings in the type of boiler/furnace.

hr

My money would be on

a condensing tank type water heater or an indirect connected to a condensing heat source, if gas or LP.

The best equiptment for your application would depend on a number of things.
Useage how much hot water do you need and how soon? No substitute for storage if dump loads (large tubs) are in your plan. Or lots of BTU/ hr on tap.

How cold is your incoming water and how hot do you want it. This would be important for sizing the horsepower or BTU input.

Fuel source?

Also water quality hardness, chlorine, ph, iron. etc. Hard water is very tough on indirects that use tightly wound fined tube HXs. Performance suffers from day one on that mix.

If you can live within their restraints, instantanous makes lots of sense. Modulating condensing, again would be my choice. The equipment from Japan looks impressive in this arena. Rinnai has some nicely built stuff. Again hard water deposits in the small HX tubes will mess you up.

Thinking electric heat sourse? Some would argue that a ground source heat pump is worth a look. You did say money wasn't an issue didn't you

A wood fire with a tripod and kettle works well also if your off grid Very dependable and parts in-intensive Even a struggling actress on Survivor can run this setup

At my home I run a solar collector (should be mandatory on all new homes glycoled and connected to a Ford 65 gallon stone lined indirect, then a wood fired boiler and Ford indirect, then last online is a Phase 3 indirect coupled to a LP fired Weil GV Gold boiler. My shop has a MZ with the intergral domestic indirect. A small but powerful package.

hot rod

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Tony_4

Electric

is the most efficient...almost 100%. But dont confuse efficiency with cost.
If you live where the sun shines and dont mind a small upfront cost...solar is the cheapest.
But I have found the best system for upfront and operating cost is an indirect water heater connected to the fuel of your choice.

Bill NTSG

Re : Electric

100% ? How efficient do you think the fuel used to make the electricity was? 40% ?

hr

I agree, Bill

the number I see most often is in the 33- 35% efficiency range for electric generation. I'm not a proponent of electric resistence heat even at out 7 cents a KW rates!

I imagine a barrel of crude pumped from the ground in Kuwait, refined, tankered across the oceans, stored, trucked, pumped into bulk storage, security and fire prevention costs, pumped out of storage, trucked by diesel to your home, pumped again into you tank, then burned at 85% efficiency has some "costs" associated with it! :0 Assuming, of course, none is spilled along the way! then the price really skyrockets depending on who pays the cleanup costs.

Also factor in the multi billion dollar "war machine" that keeps most of the worlds oil flowing this way

ALL energy "costs" a lot more more than meets the consumers eye. Solar and a natural gas well in my back yard would be a sweet setup.

hot rod

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Bob Bona_4

you

are ahead of the game with your existing boiler. Use it! Phase 3 indirects are a favorite here in the Bona camp. There's nothing sadder to see than a boiler sitting in basement in the summer twiddling it's thumbs when it could be busy producing hot water in some way.



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Herb

40 gallon

conventional vented water heater cann't be beat for the average family of 4 given its limitations. Why are you thinking of changing? Have your needs changed or is the old boy not keeping up like it used to? The stand alone pilot operated gas water heater is extremely dependable, relatively disposable in hard water situations, runs when the power goes off etc. but if you need large quantities of hot water, looking for the best stand by losses, like to keep your boiler excerized all year etc. run a zone off your existing boiler to an indirect, if your water's not too hard! Remember you're at a site filled with great techs who can change out a boiler as easy as they can change a thermocouple. We tend to love the technology and sometimes lose sight of the goal so keep in mind simpler is often better IMO. Herb

Roger Litman

Indirect water heaters

AS I am in favor of boilers running all year round and that their output is usually two to four times that of a gas fired water heater and their life (if you don't use a glass lined unit) in the ten to twenty year region. I recommend using one of the indirect units for both long term life and efficiency of cost. We have indirects operating for as little as fifteen dollars a month during the summer and have found that they are tough to beat on the production of hot water.

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Tony_4

I agree with both of you

you can add the the events of 9/11, the cost of this new war on terrorism and the 34 billion we give isriel every year to your energy cost.
If you sit back and look at the numbers...like the fact we consume almost 150 billion gallons of gasoline a year and the government collects 50 cents a gallon in tax it becomes obvious we created a monster that is not going to slow down. Oh did I forget to metion how palestinian children are used as slaves to pump that oil in countries that still have kings..yes thats right ..a king.
Or you can turn on your tv right now and watch some more women and children get killed in south america. noone cares anymore Bill and worrying that electic generation is inefficient is like some small attempt to show you care.
I was only stating that once you have purchased the energy you can use it at 100% efficiency.

Frank Cheng

some questions for you, hot rod.


How is your experience with MZ. I put in two MZ40 3-4 years ago. They both run fantastically except for a few drops of water leak from air vent and pressure relief valve. In one place, I save about $1000 a year. So I already earned the boiler cost back by now. I will soon put another one in. I have not tried their oil fired condensing boilers and like to find out how people feel. Have you used one of these. If so, you do you feel? And how about their indirect hot water heaters? Have you ever tried these units yet? Thanks.

Frank

jfox

hr

Would you explain what "a condensing tank type water heater " is?

Thanks,

John

heretic

Ask a simple question...

From everthing I have seen, conventional gas water heaters are typically only about 70-75% efficient, but they offer a very low upfront cost. (This is simply heat transfer efficiency, and should not be confused with the DOE Energy Factor (EF) rating, which takes other factors into account).

Switching to an indirect may result in long term savings if your boiler operates more efficiently than that.
Some factors to consider with Indirects:
1) Standby losses in the summer can be substantial for a standard high volume boiler that is not insulated.
2) A large boiler may not attain peak operating efficiency during short replenish cycles.
3) Indirects are typically more expensive upfront, often 2-3x more than a conventional gas WH.

Very efficient standalone water-heaters are available, such as the AWH Polaris (90+%), though these do not come cheap, so you would need to carefully consider the payback interval.

Dave Yates (PAH)

E-Force

There is a quiet revolution taking shape in this country & I couldn't be happier. Virtually every major manufacturer has woken up and is (finally) smelling the coffee.

Burnham with the Opus

Heat Transfer Products with the Munchkin

Peerless with the Pinnacle (a Munchkin in disguise)

Weil McClain has thrown their hat into the ring

and now, Bradford White with the E-Force 98%+ water heater.

I'm telling you, it won't be long till other countries will be seeking out our USA products!

I'n not bashing or discounting foreign products. Quite the opposite. Just like the 70's energy crunch and the slap Detroit needed, the foriegn hydronic products have driven the US market to new heights. That's good for us all.

We've installed all of the above, with the exception of the new E-Force BW water heaters, but we've got a batch of them lined up for installation in another two month's time.

The MZ we installed does purr like a kitten, the Munchkin has caused the gas company to question why our customer's usage has dropped so dramatically and an Opus resides in my basement.



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Bob Bona_4

you

got an Opus Dave?! Spill forth some pic's and a testimonial; inquiring minds want to know...

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Bob Bona_4

PS

I KNOW you have a walk in basement Dave

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