Considering switching to tankless water heater. Busy house, lots of kids, so the neverending supply seems attractive.
I have always heard that they have trouble really heating the water hot enough, especially here in the upper midwest when water comes out of the ground pretty cold (maybe 40 degrees??)
Any experiences out there?
Get a gas fired high efficiency water heater. Have you ever put a thermometer on the water coming out of the ground?
If you size it right and install it right it will do the job, it just takes research. I have a small 117000 btu Bosch that heats 34f incomming for a hot shower not even being set to high. For a family you will need one sized , it will im sure be 180000 btu +. Proper gas supply must be measured since these pull more gas than most furnaces and when everything is running-pulling gas a test must be done with a Manometer. So install can cost to upsize Ng lines. The upside is even Sears for example their best Ng tanks have an energy factor rating of only in the
60s, tankless go from 82-90+ and have efficiencies of up to 94 for a Talagi tk1. An upside is you will save on gas and considering 1/3 of Ng usage can be HW, it can be alot. The downside is Endless hot water, that premotes waste. Look at Takagi and Rinnai 188000+ btu units with remote thermostat. Measure incomming water temp, Im near Chicago and incomming is not as cold this year as we are having a warm winter, so take off 10f on your temp , or if incoming is 40f figure at -15 - 20f it will be 33f for your calculations. You also need to measure Gpm that you have.
"Tankless" hot water is a system where the heating system boiler is designed and fitted with a copper coil that installs into the boiler where the domestic water is heated by the boilers water. This is not to be confused with an "indirectly fired hot water" tank which is a large storage tank much like a gas or electric hot water heater that has coils inside the tank that run hot water from a separate zone on your heating system boiler through the tank to heat up the domestic water inside the tank.
Tankless systems would never be considered if you are looking for endless hot water. They produce between 4 to 7 gallons of hot water per minute depending on brand, size of boiler, and age of unit. When large amounts of cold water run through the tubes in a smaller system the water would barely get warm. I have one in my own home with teenagers. Trust me on this one. They work best in low volume households.
What you want is the indirectly fired hot water system. I have installed many of these systems in new homes and my customers love them. Get a 74 gallon tank and you are good for 4 teenage girls and a wife with a whirlpool tub.
Ground water is generally 55 degrees, globally, if not drawn from near the earth's surface (dug wells).
Whoops. Strike that "globally" part. That's the temp in MY AREA. Ground water temps vary globally. Mouth runs faster than brain.
BP the tankless he is refering to are stand alone units like Bosch Takagi and Rinnai
I am not sure you really want a tankless system. You will need to get one with a capacity large enough to supply the maximum amount of water being used at any one time. That means if you have two showers and a dishwasher and a clothes washer all running at the same time, you are going to need a really large capacity unit. If you only have one shower and will not be doing dishes and washing clothes all at the same time, you should be OK.
I might suggest that a conventional system should also work. The only real difference is the buffer. You tank type heater heats up a large volume of water and it is available for use. You can use very high volumes of hot water, but only as long as the total gallons used does not go over the standing capacity of the heater. Even when being used some heating can be going on to allow a constant usage of hot water as long as it does not go over the capacity of the heater.
The standard tank heaters can have different tank sizes and they can have different recovery rates. I suspect you can find one that will have a large enough tank and recovery rate to handle your needs, just as you should be able to find a tankless unit with a high enough rating to handle your needs.
How many showers do you have now, what size heater (gallons and recover data)? Are the showers old pre-restricted shower heads?
Sounds intriging. And probably only a matter of time before one of my customers asks me about them. Got any links? I'd like to take a look.
It could feel like 40. Water is colder than air at the same temperature.
I was researching the very same thing a few months back. I live in the Philadelphia area so in the winter the water can get pretty cold. I found a DYI article about an electric version (I don't have gas in my house), and it looked pretty good, but I remember there being an issue with a limit on the max temp the water could be raised as based on the temp coming from the ground. I was looking for something for 3 baths, washer, and dishwaser. Cost was about $800 for the unit.
One link I found was
Jack, I recently replaced an old State water heater with an outside Rinnai tankless (model 2532) about a month ago. My water heater was in the attic which I did not like, so I was planning to re-locate whatever replacement I ended up choosing. My neighbor had gone with a tankless about a year earlier and they had liked it, so I decided to go that route myself. No issues whatsoever with it heating water hot enough, and plenty of it. I have four people (two adults, two children) in a 2400 sq ft home in North Carolina and so far am very pleased with my choice. Just for comparison sake based on different price quotes I was given, the tankless unit cost me $400 more than a traditional tank unit would have cost me (in both cases I was moving the location of the water heater). For me the extra cost was worth it to solve the attic locaton problem I had with a solution that I did not have to deal with in my already cramped garage. YMMV. Bob T.
Three years ago when I built a new house, I looked at tankless heaters; but I opted for the forced-draft high-efficiency tank type. One thought I had was that in a 2-story house with most of the water use on the first floor that I would have 50 gallons upstairs to use via gravity feed for flushing, washing and drinking in the event of a failure of the city system. "Doesn't happen." the neighbors said.
But, since I've been in the house it has happened -- several times. Pipes break, there was a regional power failure and then an overworked system for a while one summer. Last one was a cold winter day 3 weeks ago when the main down the street started leaking. My little gravity system worked simply by closing the main house valve and opening a faucet upstair to break the air lock.
I doubt that there is much of an energy use differential between a tankless and high-efficiency tank system for the same volume of water (it would be good to see an unbiased comparison); but, so far, I've found the tank system to be worth the slight extra cost.
TKM
"BP" wrote in news:gKydnc-Pwrs- ZUnenZ2dnUVZ snipped-for-privacy@conversent.net:
Here's the Rinnai link:
Pick
Tankless are rated on gpm and temp rise. If you have 6 gpm incomming at the main and your tankless is rated for 6 gpm @ 100f then you can open every faucet in the house and get water 100f hotter then incomming. With units out putting near 200,000 btu as standard for Rinnai and Takagi you have alot of power to heat. Tankless have modulating gas valves, my small unit modulates from apx 25000-117000 Btu. Mistakes are made by underestimating incoming flow and lowest winter water incoming temp and undersizing the Ng line, wich must be tested with everything competing on. Sears best Power miser Ng water heater have an energy factor in the
60s. Tankless are from 82-90+. This is your true energy rating of true efficiency. My 800$ Tankless will pay for itself in 3 years from my well insulated electric tank. That is an investment return of 33% per year, I can think of no other better investment ive made.
Yes.
Yes. It's colder in comparison with a warm object (such as your body).
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