Author Topic: Hot Water Heater Suggestions.  (Read 2583 times)

gardeningandgreen

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Hot Water Heater Suggestions.
« on: November 10, 2016, 12:40:39 PM »
Hello all,
I live in an old house that has an old electric hot water heater that has seen better days. It looks like a late 80's model. What we are trying to decide is should we get a new tankless hot water heater or one with a standard tank. Also any advice on what brands would work well. Another consideration is ease of installation as we plan on doing it ourselves. Thanks in advance!!!

lthenderson

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Re: Hot Water Heater Suggestions.
« Reply #1 on: November 10, 2016, 01:01:39 PM »
There are many threads already on this subject.

Depends on where you live and the quality of your water. Especially with hard water, tankless heaters have a finite life just like conventional tank heaters while costing 4 to 5 times as much. It that price premium for unlimited hot water worth it is a question only you can answer.

Eagle Glides Ascending

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Re: Hot Water Heater Suggestions.
« Reply #2 on: November 12, 2016, 08:22:34 PM »
I replaced my old electric hot water heater with a GE Geospring hot water heater.  The hot water heater uses a heat pump and traditional resistive heating elements, so it is more efficient that a conventional electric hot water heater.  The cost was $800, but it qualifies for a $300 federal tax credit and my local utility gave a $500 rebate, so my cost after the rebates was only the sales tax.  I've been very happy with the purchase so far.

mires

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Re: Hot Water Heater Suggestions.
« Reply #3 on: November 12, 2016, 08:57:41 PM »
Electric tankless water heaters are very expensive to run. You also have to hire an electrician to come in and upgrade your electrical service as they are very power hungry. Gas units are much better but in most cases will never pay for themselves like people think they will. Your best bet is to stick with a traditional tank or install a heat pump water heater. They are far more efficient but more expensive to purchase. There is a $300 federal tax credit on them until the end of the year and you may even be able to get a tax credit from your electric company.

solon

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Re: Hot Water Heater Suggestions.
« Reply #4 on: November 12, 2016, 09:32:25 PM »
Another advantage to a tankless water heater is endless hot water.

In our house we have a giant garden tub. It doesn't have jets or an internal water heater. When we tried to fill it, the old water heater ran out of water before the tub was full. So then we sat there, up to our waists in water, shivering.

But when we installed a gas tankless heater, then we could fill the tub as full as we wanted, without running out of hot water.

MMM98

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Re: Hot Water Heater Suggestions.
« Reply #5 on: November 16, 2016, 10:21:23 AM »
I have a rinnai tankless HWH that I installed on my main home.  For the vast majority of people it will not save you much.  The payback is about 20 years.  It is because most the energy goes into heating the water, not maintain the heat in an insulated container.  Also with a tankless you have to be aware of a 'cold sandwich'  Example I take a shower, the heater senses the flow of hot water and heats it.  When I am done the water is not heated but hot water remains in the pipes.  Next my wife takes a shower.  She gets instantaneous hot water since it is already in the pipes.  There is a delay while the tankless senses the flow of water.  She gets a hot -COLD- Hot shower.  There are a couple ways to avoid this but you need to be aware of it or deal with it.

I knew all of this before I installed mine, so why did I do it?  First I did it myself so the cost was not dramatically more to install, second I replaced two heaters.  Therefore I avoided the cost of keeping 100 gallons (2 tanks) hot.  The savings tipped the scale in favor of tankless.  Also you might need the space savings that tankless affords.  Here is another idea to save water heating costs, a tempering tank which I discuss here under post #4 http://forum.mrmoneymustache.com/do-it-yourself-forum!/domestic-waste-water-heat-recovery/msg1306604/#msg1306604

LPG

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Re: Hot Water Heater Suggestions.
« Reply #6 on: November 30, 2016, 08:58:44 AM »
Do you have natural gas installed at your house? If so, it probably makes sense to switch to a natural gas water heater. With current energy use and pricing, those are always cheaper to operate than electric heaters.

After that, it's important to consider how you use water. Long showers, or short? 1 person in the house, or 7 (Whoa, that would be a lot). If you use a lot of hot water, the tankless natural gas heaters may be a good idea. Depending on what model you get, they can be quite a reasonable price. A smaller unit, capable of delivering hot water to "only" 2-3 showers at a time through Rinnai, can be bought for something like $300-400. And they are more efficient, so using more water means more savings. Another thought, somebody else mentioned the cold water sandwhich problem. I have two comments on that:

1. This can be mitigated by the design of your plumbing system. If the shower is really close to the water heater, and there's very little plumbing in between, you're gonna have a problem. But it your shower is in the far corner of a large house, then there's enough heat in the water/pipes between the water heater and the shower that people rarely encounter that problem.
2. It can be mitigated by including a small buffer tank in the water heater. The Navien tankless water heater does this, and recirculates water through a 0.5 gal tank to keep that buffer hot at all times. They avoid the cold water sandwhich problem that way. I personally think it's a pretty silly solution, that obviously decreases the efficiency of your high efficiency equipment, but it does mitigate the cold water sandwhich while still being more efficient than storage tank water heaters.

If you don't have natural gas on site, the highly efficient option is a heat pump water heater. They're efficient, and expensive. The choice again comes back to how much hot water you use, and what you care about. If you use a lot of water, it may be an economical choice. If you care a lot about energy efficiency, even if it isn't economical, it's a good choice. If you use a little water, and are primarily motivated by the economics, it isn't. In that case, it's probably best to stick with the electric resistance tank and look at other ways to save on water heating energy use (Low flow fixtures for example).