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I bought a small condo under 500 sq.ft., with a 30y.o. rusty, leaking and smelling electric water heater (w/ 30G tank). The water heater is, obviously, to be replaced. Hot water is consumed by 1 shower, 1 bathroom faucet, 1 compact washer, 1 dishwasher and 1 kitchen faucet.

I see the following options:

  1. Single water heater with tank. Replace for the almost same model, but new.
  2. Single tankless water heater, to save some space in the utility closet.
  3. Single heatpump water heater with a tank.
  4. Multiple (5) point-of-use tank-less water heaters, installed right where it is needed: near shower, faucets, dishwasher and washing machine.

I need help deciding between those options. What are the main factors, by which do I compare those options?

Here is the preliminary research I did: 1. I started with: cost of the unit, cost to install, cost to operate, noise and projected lifetime. 2. The approximate water flows are: 1.5 GPM for faucets and dishwasher; 3.0 GPM for shower; 2.5 GPM for the washing machine. + 1 GPM extra. 3. My ground water temperature is 52degF.

1 is: $300 for the heater, $1200 for professional installation. $300 for DIY. Noise: very small. If previous water heater survived 30 years, then almost no maintenance is required for another 10-15 years.

2 Tankless can run about $530 (Ecosmart 5GPM). The utility closet is far away from the circuit breakers. So 3 x 40 AMP breakers and proper (#6 gauge) wire has to be wired over existing structure. Easily, $400 for professional wiring, $100 for DIY, but a bit complicated for me. + $1500 cost of professional installation, about $300 for DIY. Noise: negligible. Rumors are that maintenance (descaling) every year is required.

3 Heat Pump Heater: (e.g. Rheem) Very expensive: $1400 + I can assume expensive installation on the order of $1500. Consume less electricity to operate. May require extensive maintenance. Noisy: 49dB. Has 15 year warranty and may have some energy rebates.

4 Multiple POU units. Each of them have to sustain either 1.5 (faucets) or 3.0 GPM (shower and washing machine). 1.5 POU units can be hooked up to standard 120v, no rewiring required (e.g. Ecosmart POU 3.5). 3.0 GPM ones (e.g. Ecosmart POU 6) will require single 30Amp line and a breaker. $150*3+$200*2=$850 for a set of 4. Some small installation required. Not sure about maintenance. Noise: negligible.

Price of DIY installations does not include exisitng tank heater disposal. I am personally inclining to #4, to get rid of one big central heater at all.

Please tell me, if I have determined the comparison parameters right? Is there another dimension to compare those 4 options? Is there anything I have missed? Is there anyone who did #4 and is happy with that?

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    Whoever said you can do 1.5gpm on 120V needs to check the realistic temp rise data. – Harper Apr 4 '17 at 0:14
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    I vote for 1. Replace with a modern electric 30 gal or 40 gal tank. – Jim Stewart Apr 4 '17 at 1:47
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    Can you explain your math for option #4? I get $850 for a set of 5 by your own breakdown, not including installation (and a new 30 amp circuit will not be cheap or uninvasive). – Jimmy Fix-it Apr 4 '17 at 2:02
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    JimmyFixIt has covered my thoughts in his answer. You already have the plumbing for a central heater. A replace with same kind is the cheapest solution and the least disruptive. I cannot imaging that professional installation of a 30-gal tank electric water heater would be as much as $1200, but maybe I've lost track of prices. Where are you located? – Jim Stewart Apr 4 '17 at 16:24
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    Is your current heater a squat form or a tall form? – Jim Stewart Apr 4 '17 at 21:25
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Option 1 (replacing "in kind") will not only be cheaper but will be minimally invasive. The cost of the "hassle" is tangible and should be included in your selection process. Amortize the total cost over years of expected service, include the hassle factor, and I think you will find it the best option.

  • Thank you for your input. I am weighing the cost of "hassle" against the cost of renting a storage unit if I do not get rid of the bulky water heater. Over the years of expected service, this comes to no small value. Something like $50*12*15=$9000 for 15 years. This outweighs any initial investment. – mzu Apr 4 '17 at 14:42
  • On the other hand, if those tankless options are very expensive to maintain that might cost me a lot. At this point I can not get a plumber from a reputable company (I tried 3 so far) willing to do an electric tankless install and maintenance for me. This alone says a lot to me. – mzu Apr 4 '17 at 14:45
  • By maintenance, I meant: "I am not able to find a plumber from reputable company to commit to a maintenance plan after install". – mzu Apr 4 '17 at 14:52
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    There is no electric tankless central heater available that would be adequate. The electric current demand would be well over 100 A at 240V while the heater was on. The only central tankless water heater that would be adequate would be gas fired. A new apartment like yours could be designed and constructed with point of use electric tankless or mini-tank water heaters (at greater cost), but retrofitting to point-of-use would be prohibitively expensive compared to a central 30-gal tank. And the electric tankless heaters occupy significant space. You are thinking that they occupy zero. – Jim Stewart Apr 4 '17 at 19:41

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