Replace WH now or wait for new improved one?

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Queen50

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I have a 40 gal electric water heater that is 10 years old and slowly fading. It's too small for our needs now and we want to replace it with a 50 or 55 gallon. I'm trying to decide whether to do it now, or wait for the new more efficient units to come out.

I know I need a cost/benefits analysis of some sort, e.g. how long would it take for the additional cost of an improved unit pay off in savings? Would there be additional installation costs? (I don't think space will be an issue, but the input line may need to be moved higher, etc.)

Would a plumbing contractor be able to help me with these type of questions?
 

DonL

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As far as I know, The new ones are available now.

About all a person can do is buy one with a good warranty.

Good Luck.
 

Cacher_Chick

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My 25 year old heater is still working fine. The average lifespan of a new heater is 8 years. Seems to me that the quality gets worse every year, so doing anything is a gamble.
 

DonL

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My 25 year old heater is still working fine. The average lifespan of a new heater is 8 years. Seems to me that the quality gets worse every year, so doing anything is a gamble.


They do not build them to last like that no more.

The New ones may shut down, When the electronic Timer times out. Yet to be seen.

I did hear prices are up a bit for the new "safe and green" ones.


Some people are having a hard time getting water to heat.
 

hj

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The latest report is that you will NEVER recover the added cost of the new heaters. IF it is over 50 gallons, it will have to be a hybrid heat pump model, meaning that it will be MUCH more expensive AND larger so do you have the space for it? Even the 50 gallon and smaller ones will be larger than what you have now.
 

Master Plumber Mark

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the new heaters will cost about at least 100 bucks more and
they wont even say how much larger in diameter that they will be...

so if you got a tight spot, it will be rough to install.... they are not gonna save you a dime over
what you could do with a 25 dollar water heater blanket.. so bacically it is a cluster/uck...

I would buy one now before you have to pay another 100 bucks
 

Dana

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In WA electricity is comparatively cheap, but with subsidy there may still be a financial case for a heat pump water heater.

A 10 year old HW heater has anywhere from 0-15 years more of service life left, but if it's not meeting your current needs, this is not purely a financial play. The bigger question is why/how the current HW heater is too small for your current needs, since upsizing by 25% in volume may or may not satisfy those needs.

And what do you mean by "... is slowly fading..." ??
 

Queen50

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We had 3 people and two bathrooms in the house when the water heater was new. We've since put another 3-piece bath in the basement, and there are 7 people here now (4 adults, 2 teenagers and a grade schooler). Hence the need for a larger WH.
 

Dana

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What's the mix of shower bathers vs. tub bathers?
 

Queen50

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Only one bather and one excessively long showerer. The rest of us are normal shower people. So far we're getting around by staggering showers and running the dishwasher later at night.

Even so, when I use the master shower I have to keep adjusting the water temp up as I go. The WH also doesn't seem to recover as fast as it used to. We're on a well so it's possible there's a bunch of sludge in the tank, given it's age, but my husband is afraid to try to drain it in case it makes it worse.
 

Dana

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Only one bather and one excessively long showerer. The rest of us are normal shower people. So far we're getting around by staggering showers and running the dishwasher later at night.

Even so, when I use the master shower I have to keep adjusting the water temp up as I go. The WH also doesn't seem to recover as fast as it used to. We're on a well so it's possible there's a bunch of sludge in the tank, given it's age, but my husband is afraid to try to drain it in case it makes it worse.

With that many people 50 gallons won't be enough tank on it's own, but an 75-80 gallon unit would probably cut it.

In the mean time, increasing the storage temp on the water heater to it's maximum setting (assuming it already has a tempering valve or thermostatic mixing valve on the output, per code) will increase the apparent capacity some.

With a predominantly showering family (and one shower-abuser) there is also pretty good capacity extension and payback by installing the largest drainwater heat exchanger that fits down-stream of the most commonly used shower. That probably won't work for the basement shower, but you probably have at least 5' of vertical drain somewhere down stream of the upper floor showers accessible in the basement. Fatter and taller both count for boosting return efficiency, and a 4" x 48" or 3" x 60" will deliver more than half the heat going down the drain back to the hot water heater and to the shower. That increases the showering time by a substantial fraction, and cuts the recovery time literally in half, since instead of having to heat 40F water up to 106F+ to make the next shower tolerable, it only has to heat it up from ~75F. At full retail they're pretty pricey, but with a credit card and a phone call you can open up an account at EFI, and get their published wholesale price. It's a reasonable DIY project for those with plumbing skills.

ThermoDrain-drain-water-heat-.jpg


Key to getting the full efficiency out of them is to feed both the input side of the water heater as well as the cold side of the shower. It's often more convenient from a plumbing perspective to feed the whole cold distribution plumbing with the output of the heat exchanger rather than isolating the cold side feed to the showers. In practice this has no significant consequences- the most significant of which is that the cold water coming out of the other taps when someone is in the shower is essentially room temp rather than cold-cold when someone is in the shower.

They do nothing for tub-fills however, since the heat can only be recovered if the drain is flowing while the potable water is flowing.

This would add more apparent capacty than bumping up to 50 gallons, but not quite as effective as installing 80 gallons. But at your level of showering use it's also worth doing simply on financial grounds no matter what sized tank you installed.

A potential cure for the shower-abuser is to install occupancy/vacancy sensor switches on the bathroom lights, set to time-out and turn the lights off if no motion is sensed for 10 minutes. (This worked for my kid, anyway.) You can get 'em for $20-30 at box stores- just read the specs on how it works an make sure the time-out options work for you. Some can be set for either manual-on, auto-off or motion-activated on, which is the mode you want, since you want the lights to come on as soon as they step out of the shower rather than have them fumbling to find the switch in the dark while they are dripping wet. Search the websites for "occupancy sensor switch", you'll find them.
 

DonL

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Wear bathing suits and shower together.

Some people are lucky to have running water, let alone Hot water.

Spoiled we have become.

My bad.
 

Dana

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In western WA they never want for running water, though this year's record-low late winter snowpack in the Cascades might make it a little too interesting if it doesn't pick up before summer, which may affect late summer power capacity too, given the prevalence of hydro driving the PNW grid.

If natural gas is available, a 50 gallon gas-burner + drainwater heat recovery could pretty much keep up with 2 simultaneous shower with modest recovery time between the next batch.

If the space is available, an 80 gallon heat pump water heater + drainwater heat recovery unit would do OK and would use even less power, but the recovery periods would be as long or longer than what you're currently experiencing. It's a pricey piece of hardware (about $2400 for the well regarded Stiebel Eltron Accelera 300, $1800-2K for GeoSpring et al), but with your hot water use it may eventually pay off on power use, but not nearly as fast as drainwater heater recovery would. They're all pretty tall 6' or taller, and they're not exactly quiet, but they help dehumidify the basement (assuming it's installed in the basement.)

There may be rebates available for either heat pump water heaters or drainwater heat exchangers your area, depending on which utility is serving you. (PSE kicks back $250 for any drainwater heat recovery heat exchangers with better than 42% return efficiency, $300 for heat pump water heaters.) Got a ZIP code, or the name of your electric utility?

The 80 gallon heat pump water heaters are rated between 75-85 first-hour gallons, but in combination with drainwater heat recovery it's substantially more than that. A standard 50 gallon tank is good for about 55-65 first hour gallons (as are some 50 gallon hybrid heat pump water heaters), a standard 40 gallon unit is good for maybe 50-55 first-hour gallons. From a showering-use-only perspective a drainwater heat recovery unit of sufficient size will get 65+ first-hour gallons out of a 40 gallon electric, but not more than 75. At typical shower head flows you're probably looking at about 15-25 minute of showering time in that first hour with your 40 gallon tank, which is about 2 showers or 3 fairly short ones. With drainwater heat recovery you should be able to get 3-4 decent showers before having to wait, with a shorter waiting period. With an 80 gallon tank (standard, or heat pump type) you'd get in 4-5 showers, but in combination with drainwater heat recovery you'd be able to shower all 6 people in rapid succession without much concern about running short.

Unless you are heating the place with electricity, water heating is easily the largest chunk of your power bill- it could be more than half. (I'd need a lot more info to be able to assess that.) With drainwater heat recovery + heat pump water heater you'd be using less than 1/3 (and possibly less than 1/4) of the electricity for water heating than currently.

If you're not all showering at the same time of day (3-4 in the AM, &/or 3-4 at night) you may do just fine retrofitting the heat recovery unit and deferring the decision on the water heater itself. If that works, it's probably worth bumping to 50 gallon GeoSpring (about $1000 at box stores) if there are subsidies available, since it has the same first-hour ratings of standard hot water heaters, but uses half the power. The ~$300 difference in unit cost between a subsidized HPWH and a standard 50 gallon unit would be recovered in lower power bills in less than 5 years, maybe under 2 years at typical WA electricity prices, even if you have the drainwater heat recovery in place.
 

Queen50

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Thanks to all for the info. There's a lot to consider! I don't think 80 gal would work in our space.

My current WH is electric. We have propane on site; can it be used on a gas unit? The cost of running the gas line from the tank would also have to be considered.
 

Dana

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In the PNW heating hot water with propane costs about the same as dumb resistance electricity. But a fast-recovery 50 gallon propane tank HW heater(eg. AO Smith GCVX-50 LP) can deliver 90 first-hour gallons.

In combination with drain water heat recovery you'd then be approaching "endless shower" territory.

You can't fuel a natural-gas HW heater with propane (if that's what you were asking), but propane HW heaters don't have substantially higher first-cost. You can use a drainwater heat recovery heat exchanger with any type of hot water heater (except maybe a big tub on an open fire :) ), if THAT is what you were asking.

Before making that step you have to be sure that you have a sufficient remaining capacity on the propane regulator & tank. If you're primary use for the propane is cooking this will be a big change, but the regulator is probably big enough. If your primary use is space heating you could conceivably run into capacity issues when adding a 50-60,000 BTU/hr burner.

When moving to propane you also have to figure out the exhaust venting and make-up air issues, which aren't always easy when replacing an electric tank with a fossil-burner. Electric tanks can be installed pretty much where ever there is space, unlike a propane HW heater. The initial installation would be pretty expensive ( and it won't save money and might even cost more per shower), but it addresses the capacity issue.
 

Dana

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That's true, but in a basement it also dehumidifies the space, and if installed a garage (fairly common in WA) you really don't care, eh?

In a basement installation the modestly lowered room temp lowers the actual heat loss out of the house too. It's not a simple model of the room heat going into the hot water adding exactly that amount of heat to the space heating load the way it would be if it were in the fully conditioned space.
 
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