Small tank water heater for sink and dishwasher

[BogleMe]

In the middle of a kitchen renovation.

To complement my gas tankless heater, by reducing time for hot water to arrivate at tap, I'd like to install a small electric tank heater that would service my dishwasher and sink, both next to each other. I know such a thing can be devoted to one appliance, but could it service two?

Thanks for any help.

[neilpilot]

The way to reduce time to tap but retain the economy of the primary gas fired tank is to plumb the hot water tap into the local electrical water heater. If you are installing it this way, then you shouldn't have an issue with capacity.

OTOH if you plan to heat from the cold water tap then all bets are off.

[BogleMe]

The way to reduce time to tap but retain the economy of the primary gas fired tank is to plumb the hot water tap into the local electrical water heater. If you are installing it this way, then you shouldn't have an issue with capacity.

OTOH if you plan to heat from the cold water tap then all bets are off.

I think I understand your first point - and that would be the typical manner in which a plumber would install it correct?

On the second point, why would someone heat from a cold water tap?

I am an extreme novice on this stuff if you can't tell. We'd have a professional do this - I am just curious if it makes sense.

[boomer_techie]

On the second point, why would someone heat from a cold water tap?

Some (under sink) water heaters can't be used with hot water coming in - presumably their control logic can't deal with rapid input temperature variations.

[Ping Pong]

How far away is the heater now? It could just be that your pipe diameter is too large. Oftentimes plumbers use a larger pipe so they can run multiple faucets off it. You can have a small diameter PEX line run from your heater to the sink, which might solve your problem.

[Silverado]

You could consider getting all hot water for the kitchen from a small local heater. Four gallons should handle the vast majority of kitchen tasks. So cold water supply splits and the hot water supply from main heater is capped off.

That paints you into a corner. A pretty efficient and quick responding corner, but still a corner. I’d probably add a valve so I could switch it for the heavy use holiday season.

[2babogle]

Your dishwasher has a heating element in it. You probably don't need to give it immediate hot water. It will take care of itself. If you're concerned about your sink water that's a different issue.

[wilked]

Be sure you're not solving a problem that doesn't exist.

How long do you want / willing to 'wait' for hot water? Is it 1 second? 5 seconds? 10 seconds?

[Silverado]

Be sure you're not solving a problem that doesn't exist.

How long do you want / willing to 'wait' for hot water? Is it 1 second? 5 seconds? 10 seconds?

It’s 2021, I’d say two seconds is absolute max.

[wilked]

Be sure you're not solving a problem that doesn't exist.

How long do you want / willing to 'wait' for hot water? Is it 1 second? 5 seconds? 10 seconds?

It’s 2021, I’d say two seconds is absolute max.

Time is money!