Anyone have experience with tankless (instant) hot water heaters? I'm referring to the electric ones as my house will be all electric. I'm considering a Bosch AE125 to run the master bath and laundry, a second AE125 to run the hall bath and kitchen. These are rated 2 appliances and I figure by running 2 of them we can take showers at the same time or run the diswasher, hall shower, and laundry, etc. I am hoping to make my new house as cheap on electric as possible.
Tankless hot water heaters
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Two threads already started - do a search.
I'm thinking they are a GREAT idea and it has nothing to do with energy prices. It has more to do with WATER prices - just got my water bill - YIKES!!!!! A local tankless sure would stop the 5 minutes of running (wasted) water just to get to the hot stuff!
I'm thinking they are a GREAT idea and it has nothing to do with energy prices. It has more to do with WATER prices - just got my water bill - YIKES!!!!! A local tankless sure would stop the 5 minutes of running (wasted) water just to get to the hot stuff!
Tankless is definitely the way to go to be as efficient as possible. My only concern would be in bathroom use... sometimes temperature fluctuation can be a problem. Taking a shower the water will go too cold, then too hot, rinse, repeat, etc... I have seen this problem with smaller units I have had experience with in the past.
Check with your dealer about that problem.
Check with your dealer about that problem.
I like the 'instant' hot water in the winter time in the 2nd floor bathroom. Saves running the water to get it hot. And if it's a long shower, the furnace takes over as the water heater eventually gets hot water, overriding the electric heating (because I have a hot water feed to the tankless unit).
JHZR2
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Id be worried that these instant ones have a much higher power density at the heater electrodes, adn may cause higher metal leach rates into your water... OK for showers and laundry, bad for drinking...
JMH
JMH
They're good or bad depending upon heat capacity. Small ones make for tepid showers at best, but at least they can be as long as you want. They're great for smaller dwellings where space is at a premium. Consider running two in series, maybe switchable, for more heating at higher volumes.
I did search first. Sorry if this is considered a Faux Paux but one post is about multi-unit apartment solutions and one was mostly about gas appliances. Not specifically about electric units. Either way I didn't want to hijack their threads for my specific situation. I'm just never sure what to do in these cases. New thread or risk hijacking?
As far as water bill goes, I'll be on a well and septic tank so pretty much "free" (gotta pay to pump it).
I'm looking at a bigger unit which is rated for my climate so it should provide enough temperature rise to overcome winter water temps.
As far as water bill goes, I'll be on a well and septic tank so pretty much "free" (gotta pay to pump it).
I'm looking at a bigger unit which is rated for my climate so it should provide enough temperature rise to overcome winter water temps.
JHZR2
Staff member
water from a well ought to be about 55F year round. A few feet under the earth its more or less constant temperature.
JMH
JMH
If you looked at the old threads, you see I question them. I looked in to them looking for a small unit I could locate closer to where I use water. Unless you do, the ''instant'' hot water is illusionary. A couple of small electric units in a house built to accommodate them might work. Check the minimum flow rate too. I don't think my 35 years old 100 amp service would support hot water on top of everything else in my nearly 2,000 sqft house. Thanks to the regulators, my electric company can't afford to upgrade older neighborhoods.
The gas units are small, but have such huge clearance requirements, that I can't put one in the crawl space where I have a 80,000 BTU gas furnace.
The gas units are small, but have such huge clearance requirements, that I can't put one in the crawl space where I have a 80,000 BTU gas furnace.
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Skin absorbs heavy metals and other contaminants that are in the water.
I have used electric tankless water heaters for several years and find that not having to worry about the hot water running out to be the biggest benefit. I can't say I saved any money as I probably took longer showers because I could.
If you have very hard water you will go through elements at a much faster rate and will experience more scale at the showerhead.
Make sure your electrical has the capacity to handle the additional draw. the unit you specify is typical for a whole house unit and draws 118 amps at full power. Two of these will trip your main breaker (200amp) if running at full power (such as filling two tubs at the same time).
You might want to add a drain pan under them in case you develop a leak so as to not flood out your house. The O-rings can sometimes leak when they get older and you will have many elements with which to spring the leak from.
Purchase several replacement elements so that you have spares around when needed. Typically the elements come on in stages and the initial stage elements will wear out the fastest. Also install a disconnect near the units for service.
As for the electric vs gas/propane savings it will depend on your energy costs and lifetime replacement costs of the units. In the Phoenix area the electric is 1/2 as much in the winter and it works out cheaper for heating water than propane or gas. In the summer the water comes out hot without the need for a heater.
Tankless water heaters, ductless mini-splits, ERV's, radiant heat, SIP's are all products/technologies that I have used and found to be superior to what is considered conventional.
If you have very hard water you will go through elements at a much faster rate and will experience more scale at the showerhead.
Make sure your electrical has the capacity to handle the additional draw. the unit you specify is typical for a whole house unit and draws 118 amps at full power. Two of these will trip your main breaker (200amp) if running at full power (such as filling two tubs at the same time).
You might want to add a drain pan under them in case you develop a leak so as to not flood out your house. The O-rings can sometimes leak when they get older and you will have many elements with which to spring the leak from.
Purchase several replacement elements so that you have spares around when needed. Typically the elements come on in stages and the initial stage elements will wear out the fastest. Also install a disconnect near the units for service.
As for the electric vs gas/propane savings it will depend on your energy costs and lifetime replacement costs of the units. In the Phoenix area the electric is 1/2 as much in the winter and it works out cheaper for heating water than propane or gas. In the summer the water comes out hot without the need for a heater.
Tankless water heaters, ductless mini-splits, ERV's, radiant heat, SIP's are all products/technologies that I have used and found to be superior to what is considered conventional.
wuli: Thanks for the info! I will definitely have to check with the electrician on the draw. The builder mentioned putting in a 300-400 amp service but I'll have to have them check. I believe some of the upper end tank versions are more efficient than the average builder spec version. I'm still researching this. I would probably make the plumbing easier if I were to put one tank in and not 2 tankless. I really want to cut my electric use. Most of the power where I live comes from coal plants with some hydro. I'm not as environmentally green as I should be but I would like to do a little bit to help.
"Cheap" and "electric heating" should not be put in the same sentence.
If gas, oil, or propane are options you should consider these before taking the plunge.
There are a few online energy-use calculators that you can use with your real world cost per therm, KWH, gallon etc. The results may surprise you.
If gas, oil, or propane are options you should consider these before taking the plunge.
There are a few online energy-use calculators that you can use with your real world cost per therm, KWH, gallon etc. The results may surprise you.
Wife's sister had them (2) installed in new home in N Dallas burb. After almost 2 years of problems including leaks, non-operation, etc mostly resulting in absolutely NO hot water for days at a time, they forced the builder to remove them.
When they did, they were told that they were the last homeowners in the subdivision to have them removed, out of over 100 who originally had them. Not sure which brand, but it sure soured them on the whole concept. Which is sad.
I HIGHLY recommend you get contacts of existing users and talk to them. Make sure they are customers of both the brand of heater AND the installer.
When they did, they were told that they were the last homeowners in the subdivision to have them removed, out of over 100 who originally had them. Not sure which brand, but it sure soured them on the whole concept. Which is sad.
I HIGHLY recommend you get contacts of existing users and talk to them. Make sure they are customers of both the brand of heater AND the installer.
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