Tankless hot water heaters

[ezmobee]

I live in a new house (<5 years) in a development where a lot of corners were cut by the builder. One of those corners was installing an undersized electric water heater right next to a gas fired furnace. This water heater starts running out of hot water towards the end of my shower in the morning. My wife and I both take showers (separately) at the same time each morning. Hers is fairly short and mine if kinda long as I shave in there. Should my current water heater suffer an untimely death I am really interested in a gas tankless heater but I have a couple questions. First is would a tankless unit be able to handle two showers being taken at the same time? I've heard that could be an issue. Secondly, approximately how much do these things cost? If I got a tank-type heater it would be a gas power-vent model so I'm already getting kinda pricey.

 

[joed]

Re: Tankless hot water heaters

The tankless could supply the water if sized properly.
The cost is anywhere for $2000-$3500. The unts cost over $1000 plus installation.

 

[sschefer]

Re: Tankless hot water heaters

Yes, a tankless, when sized properly will support two simultaneous showers. The ones you get at HD will not. HD can't sell anything over 199,000 BTU since anything above that requires a licensed contractor install.

Your primary concern will be the size of your gas line. A 199,000 BTU unit requires at least a 3/4" gas line and if you don't have that you can't do it. THe common 50 gal water heater uses a 1/2" gas line. You also need to ensure that the vent pipe that you use is stainless steel. The easiest ones to install are those that are mounted outside since venting is less of a problem.

 

[ezmobee]

Re: Tankless hot water heaters

That cost seems fairly reasonable. No worry about HomeDepot. I'm not looking to do this myself. There's a large HVAC shop close to my house and I fully believe in supporting the local economy especially right now. However, I'm seriously doubting I have a 3/4" gas line. It doesn't look to be that big. The only thing I have that is gas is my furnace. I'm also concerned about the venting. I don't have a fireplace or a chimney. My furnace vents outside via a PVC pipe. Is this at all feasible? Or am I better off just going with a regular gas tank unit?

 

[sschefer]

Re: Tankless hot water heaters

Your furnace is a direct vent furnace. You cannot vent a tankless water heater by combining the two. You'll need a plumber not a HVAC person. Decent units start around 1500.00 and work up from there. Your gas meter will determine the maximum size of your gas line. I've had cases where I had to have the meter changed but the house had several gas applicances. It can cost between 3 and 5 thousand to have one installed properly which means getting the results that you expect and 40% more to compensate for incomint water temp swings between the seasons.

Here's a tip, stay away from Bosch systems. Nothing but trouble.

 

[ezmobee]

Re: Tankless hot water heaters

You'll need a plumber not a HVAC person.

Sorry, I mentally combine the two. "Plumbing and Heating". I just double checked their website and they do everything.

 

[aspeck]

Re: Tankless hot water heaters

Was looking into some real neat systems - one where they have a gauge at each water faucet and you can set the temp you want ... it will heat your water accordingly for each faucet! These can be controlled remotely or wired in. Too much money for the application I was looking into at the time, but something I logged away for later thought.

 

[OldePharte]

Re: Tankless hot water heaters

Maybe some of you more experienced types can help out here? Why spend $2000 on a tankless unit when a gas-fired, properly sized gas hot water heater is only $400 or so?

 

[sschefer]

Re: Tankless hot water heaters

Maybe some of you more experienced types can help out here? Why spend $2000 on a tankless unit when a gas-fired, properly sized gas hot water heater is only $400 or so?

A tankless heater is on demand only. There's no fuel usage when you don't use it. The cost savings can be huge considering that a tank style water heater is constantly maintaining your water temp even when you're not using it. There is no recovery time on a tankless. It's on, use and quit. It is also not nearly as affected by incomming water temp change. A tank water heater requires many times the fuel to recover when filled with winter season cold water (40 deg avg) vs. summer season water (65 deg avg.).

Tankless water heaters do not fail as often as tanked water heaters.

The U.S. is one of the only countries that use tank style water heaters.

 

[gss036]

Re: Tankless hot water heaters

Have you bothered to check to see where the temperature is set on your current water heater. If some has been trying to save a little bit of gas and turned down below 120 degrees, turn it up a little bit at a time until get the hot water needed for both showers. I have a gas water heater at one end of the house and an undercounter electric at the other end and we have never had a problem with enough hot water w/5 of living us (4 girls and me) in the house.
I have checked on the tankless and like everyone is saying, they are expensive. My son-in-law and daughter have one and they like it, but was shocked at the price when installed.

 

[new_boater]

Re: Tankless hot water heaters

A tankless heater is on demand only. There's no fuel usage when you don't use it. The cost savings can be huge considering that a tank style water heater is constantly maintaining your water temp even when you're not using it. There is no recovery time on a tankless. It's on, use and quit. It is also not nearly as affected by incomming water temp change. A tank water heater requires many times the fuel to recover when filled with winter season cold water (40 deg avg) vs. summer season water (65 deg avg.).

Tankless water heaters do not fail as often as tanked water heaters.

The U.S. is one of the only countries that use tank style water heaters.

with all that being said what would be a reasonable amount of time to expect a break-even or actual gain for the return on investment.
with a tankless unit costing several time more i would not consider it taking 10yrs to get a return to be worth it

 

[OldePharte]

Re: Tankless hot water heaters

Here's a link about payback - http://www.askthebuilder.com/710_Tankless_Water_Heater.shtml

Obviously, your mileage may be different.

 

[sschefer]

Re: Tankless hot water heaters

A 50 gal 5 year water heater will cost $1200.00 installed. Tankless water heaters have been lasting 25 years on average. Your homes plumbing makes up 40% of it's value on average. Add in a re-circ system and you'll save thousand of gallons of water also.

 

[halas]

Re: Tankless hot water heaters

You said: "I live in a new house (<5 years) in a development where a lot of corners were cut by the builder. One of those corners was installing an undersized electric water"

I assume that you have a 30 or 40 gallon electric tank.
that should last 10 years.

Those come from the factory setting in the medium on the two thermostats next to each heating element.

Here is what you need to do.

1) unplug the unit or turn off the 220V circuit braker on your main panel marked: hot water tank.
2} Remove the two covers on the front of the tank held by two screws.
3) Adjust the thermostats with a regular screwdriver to about 75%
4) Put the small piece of insulation back and replace the covers with screws.
5) Take showers run the dishwasher and the washing machine
6} If still running out of hot water than repeat the previous steps but all the way to the 100% hottest setting.

If still prematurely running out hot water replace it. If you have extra cash get the tankless type.

 

[Tim Frank]

Re: Tankless hot water heaters

Here is what you need to do.

3) Adjust the thermostats with a regular screwdriver to about 75%
4) Put the small piece of insulation back and replace the covers with screws.
5) Take showers run the dishwasher and the washing machine
6} If still running out of hot water than repeat the previous steps but all the way to the 100% hottest setting.
If still prematurely running out hot water replace it. If you have extra cash get the tankless type.

That is spectacularly dangerous advice....for a number of reasons.
Making those kind of adjustments without checking the actual temperature of water being produced is extremely risky. Thermostats on hot water tanks are not very precise.
The maximum output temp at the faucet, that is is recommended by any competent authority, is ~ 140 F.

That should be your target.
If your heater cannot deliver enough water at that temp for your requirements, you need a larger one.

 

[okboating]

Re: Tankless hot water heaters

My parents and I booth have Bosch Agua Star Tankless Units. We purchased them about 10 years ago. They were around $500 or so back then (I think the new models are around $650). They were one of the first units I could get in this neck of the woods. I switched due to hard water. The design of the tankless has no standing water, so no deposits. The deposits would kill our old water heaters after 5 to 8 years. These units are some of the smaller ones. My parents are on city water, and with their constant pressure they can get two showers going at once, we are on well water, and sometimes as the as the pressure drops the hot water flow is to small for 2 good showers. Even with this inconvenience we LOVE our tankless. The endless hot water is GREAT, they are very efficient. The newer units can handle a higher flow rate and would be even better. The other benefit, is they are very small. A number of the manufactures even have units that mount in an exterior wall and thus take up no inside square footage at all. These outside units are not available up north, due to extreme cold.

Just my thoughts, Dave

BTW, both my dad and myself installed these units ourselves, just like regular tank units.

 

[new_boater]

Re: Tankless hot water heaters

Here's a link about payback - http://www.askthebuilder.com/710_Tankless_Water_Heater.shtml

Obviously, your mileage may be different.

so it seems to me that the slow return on investment is probably not worth it when according to the article it would take about 12yrs to break even

 

[halas]

Re: Tankless hot water heaters

That is spectacularly dangerous advice....for a number of reasons.
Making those kind of adjustments without checking the actual temperature of water being produced is extremely risky. Thermostats on hot water tanks are not very precise.
The maximum output temp at the faucet, that is is recommended by any competent authority, is ~ 140 F.

That should be your target.
If your heater cannot deliver enough water at that temp for your requirements, you need a larger one.

No need to get exited about the adjustment to 100% since that is about 140degrees. The manufacturer recommends adjusting it to your needs up to the hottest setting if you want it that way. All electric units have a built in auto safety shut off with reset button right by the adjusting screw, in case the water gets too hot.

You supposed to have mechanical limiters adjusted to your comfort level at the faucet in case you are worried about getting burned from hot water.

 

[sschefer]

Re: Tankless hot water heaters

No need to get exited about the adjustment to 100% since that is about 140degrees. The manufacturer recommends adjusting it to your needs up to the hottest setting if you want it that way. All electric units have a built in auto safety shut off with reset button right by the adjusting screw, in case the water gets too hot.

You supposed to have mechanical limiters adjusted to your comfort level at the faucet in case you are worried about getting burned from hot water.

Correct.

 

[sschefer]

Re: Tankless hot water heaters

so it seems to me that the slow return on investment is probably not worth it when according to the article it would take about 12yrs to break even

Your right, a tankless water heater is probably not for you. I have two in my house and I love them. Both are on closed loop recircs and I have instant hot water at every source. I turn on the shower and jump in. I won't be taking cold showers when they start rationing water this summer.