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ddotterer
hot water tanks

i have a gas hot water tank that is on it's last leg.i am interested in a tankless heater.i have no idea if they work well,do they keep up with demand,do they keep temp. up to a consant temp while showering and dishwasher ect.if anybody has some nohow and experiance please help me.i don't have much time till my tank springs a leak.thank you.

JLMCDANIEL
Re: hot water tanks

As far as I can tell from research, I don't own one, the problem with tank-less heaters is that they require a set incoming water temp and a controlled flow rate, and the savings in fuel is offset by the price and installation cost. I for one am not convinced they are a good investment. They do however seem to provide unlimited hot water usage.
Jack

scfd529
Re: hot water tanks

Tankless hot water heaters do supply an unlimited amount of hot water. The way they work is, instead of having a tank full of water that they are constantly heating with a low intensity flame, they use a much more intense flame to heat the water as it's coming through the unit. This requires modification of existing gas lines as well. They have to be a bigger size because the intensity of the flame requires more gas. The savings is more in the time that you are not using hot water. Where a tank type water heater would still be heating the water in the tank by constantly turning on and off, the tankless will not be using any gas during these times.

ddotterer
Re: hot water tanks
scfd529 wrote:

Tankless hot water heaters do supply an unlimited amount of hot water. The way they work is, instead of having a tank full of water that they are constantly heating with a low intensity flame, they use a much more intense flame to heat the water as it's coming through the unit. This requires modification of existing gas lines as well. They have to be a bigger size because the intensity of the flame requires more gas. The savings is more in the time that you are not using hot water. Where a tank type water heater would still be heating the water in the tank by constantly turning on and off, the tankless will not be using any gas during these times.

the biggest question i have is if i have a spring where the water coming in is 38 degrees. does the tankless heater heat the water to the desired temp which i think is 120 degrees for a long period of time.like my wife or kids taking a shower for 45 minutes.would it keep the temp at a constant or would i loose full temp.

ddotterer
Re: hot water tanks
JLMCDANIEL wrote:

As far as I can tell from research, I don't own one, the problem with tank-less heaters is that they require a set incoming water temp and a controlled flow rate, and the savings in fuel is offset by the price and installation cost. I for one am not convinced they are a good investment. They do however seem to provide unlimited hot water usage.
Jack

thank you for your reply.
so if i have a spring with incoming temp of about 38 degrees,the tankless would not heat the water to about 120 for a period of 45 minutes?plus would i have to have my incoming gas supply line increased for more gas demand by the tankless?

JLMCDANIEL
Re: hot water tanks

Yes, you would need a large gas line. For a tankless to work properly you need a consistent incoming flow rate and a fairly consistent incoming water temperature. I don't feel that the tankless units are developed enough to make them a worth while investment.
Jack

ddotterer
Re: hot water tanks

JLMCDANIEL Thanks for the info on the tankless hot water heaters.I think i will stick to the original plan and stay with the track record of the tank heaters.I think a tank heater that lasts 8-12 years is good enough for now.Maybe the next time i go to replace in 10 years or so.The tankless will be improved or a better system.

Shaun
Re: hot water tanks

There is a lot of talk on demand-type instant gas water heaters. As a plumber I have installed about 15 in the last two years. Yes they are more expensive as the unit goes and even more expensive for the initial install. Remember these are direct vented (through the sill or wall) no chimney. They need a larger gas line than a typical tank type. Because they are direct vented they also need a live wired (Mass code here) CO detector. They also need electricity. They detect the incoming water temp and calculate the amount of btu's needed to raise the temp to the desired set point. That's what makes them even more efficient than just the fact that they only run when there is a demand. They are mini condensing boilers. Most have a range of 29,000 to 200,000 btu's which means only the gas needed is used, however that ability of range requires the larger gas line. Most have a 10-15 warranty. They also are compact and hung on a wall. They do need to be sized correctly by a competant installer. The only complaint I have received is the amount of time the hot water takes to get to point z, which would be comparable to a tank w/o a recirc zone. My local gas company offers a $300 rebate on purchase and maybe Obama lets you use the energy rebate on it, check your accountant I'm not sure, but I think so.

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