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Washing machine with tankless heater

Posted by LARemodel (My Page) on
Tue, Jul 29, 14 at 18:18

I'm planning a bathroom and laundry room remodel. As part of the renovation, my contractor has recommended switching from a hot water tank to tankless.

Will going tankless be a problem for getting hot water to the washing machine? Are there specific brands or types I should consider if I decide to purchase a new washer? I think my current machine is about six or seven years old. It's a front-loading LG with steam option (which I've never used).

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RE: Washing machine with tankless heater

  • Posted by georgect Fairfield County CT (My Page) on
    Tue, Jul 29, 14 at 23:05

Before you do anything do LOTS of homework before making the tankless plunge.

Read the info. in the link I provided.
Really think about this big decision.
Research the internet, read all the pros and cons on the subject.
Personally I never liked tankless for bunch of reasons as stated in the link.

I went with an "Indirect" hot water system.
Indirect hot water systems use a storage tank that runs a loop through your already hot boiler.
I have the Buderus Logano 115WS (oil fired, hot water heating system) with LT-Series Vertical storage tank.

You have lots of options out there so check them all out.

Here is a link that might be useful: Tankless water heaters: Everything you wanted to know

This post was edited by georgect on Tue, Jul 29, 14 at 23:20

RE: Washing machine with tankless heater

To better answer your question, you will have an issue getting hot water to your LG machine. The rapid on/off pattern of the LG filling will not be enough to trigger the heater to turn on. Unless you run the hot water at a nearby sink until it is piping hot, then start the washer, once the washer has filled, shut the sink off.


RE: Washing machine with tankless heater


You make a good point.

Today's HE machines don't run straight hot (or cold) until they are filled.
They mix a little hot then a little cold (and NOT together) they switch off between the two.
Even hot isn't all hot water, it is mixed with cold to meet a predetermined temperature that the manufacture sets.
Hot can be 102 and not 120 degrees.

So a tankless systems might not work well (if at all) with HE washers.

RE: Washing machine with tankless heater

Wow! Thanks for the input! I've been tentative about switching to tankless, but did not fully understand the issues.

I live in So Calif - no boiler. I have a hot water heater tank on the outside of the house - fueled with natural gas. We always have enough hot water, even when my teen son takes long showers. My fuel costs are low, except in the rainy season when I turn on the forced air heating.

The only motivation for us to switch to tankless would be to gain a little extra space (28"x28") in the main floor powder room. Looks like I will be keeping my tank.

RE: Washing machine with tankless heater

All good posts and accurate. Tankless water heaters only run when they sense a draw and then turn on to heat the water. If your washer pulses water (runs for 5-10 seconds then stops) to conserve water, then mrb627 and georgect are correct and spot on. You will never get hot water to the washer. Most forget that thermal efficiency of the pipes removes much of the initial heat of the water. If you don't believe me, run a shower until the water is hot, stop for 3-4 minutes then shower. Your water will be much hotter.

We just moved into a new home and had the builder downgrade us to a tank gas fired water heater (with money coming back to us). I installed a heater blanket and insulated the hot water pipes. Brought it up to a 0.72 efficiency for the tech people on this forum.The water to the washer is hot and consistent although I must admit we run the washer after a shower or doing dishes.

Neighbors have the tankless and most are not happy. They get hot water but only after running the water awhile. Doesn't save water either as they run more water to get hot water (didn't make sense to me when I first heard this but now it does).

What I haven't considered and you may is putting a 10 gallon tank hot water heater in series with the washer and let the tankless feed the 10 gallon tank with hot water. That way, you will get hot water as you can set the tank water temperature higher as it's only for the washer. I know it sound stupid but what's the Internet for.

RE: Washing machine with tankless heater

LARemodel, we have a tankless water heater and are considering getting an HE machine, so I'm glad to read this.Thanks for asking the question.

Another reason to get a tank water heater is because that will be your emergency water in case we lose our water because of a natural disaster like an earthquake. We now keep gallon bottles of water in the garage (which is a nuisance).

RE: Washing machine with tankless heater

I like our tankless water heater. We have a new LG washer and I think it works for us because the water heater is right next to the washer so the run is extremely short. The hot water to the laundry sink is extremely quick as well. So you might want to consider how long the hot water has to travel. It takes a lot longer to get hot water at other points in the house.

RE: Washing machine with tankless heater

One solution would be to get a washer with an internal water heater. I'm curious, however, how a tankless heater would be worse than a tank that's a long run away from the washer. If the washer uses only a minimal amount of water, and spritzes it little by little to boot, it seems like the majority of the water coming in wouldn't be hot-from-the-tank anyway. Or am I missing something?

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