Best Instant Hot Water Dispenser (2026): Picks and Install

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Quick answer from a licensed plumber: For most kitchens, buy the InSinkErator HOT250. It pairs a 2/3-gallon tank, factory set near 200°F, with a single-handle faucet for a standard 1-3/8 in. hole, and InSinkErator backs it with a 3-year in-home warranty. Get the HOT250 hot and cold model if you want cold drinking water from the same faucet, with an optional InSinkErator filter. Choose the Moen IH2300 tank and Sip faucet for a two-step handle. The InSinkErator HOT150 has the shortest faucet. Every one needs an outlet under the sink and a tee on the cold line.

Our pick for most kitchens: the InSinkErator HOT250 hot-only system. Check the InSinkErator HOT250 on Amazon

An instant hot water dispenser is a small second faucet on the sink, fed by a tank in the cabinet that keeps roughly two-thirds of a gallon of water near boiling. It is for tea, coffee, oatmeal and cleanup, not a hot water supply for your main faucet. It needs three things under the sink: an outlet, a spare hole in the sink or counter, and a tee on the cold water line. This guide covers all three, and the maker rules for each.

Instant Hot Water Dispensers Compared

From the InSinkErator and Moen documents listed below, read on September 29, 2026. All linked listings were sold by Amazon.com when we checked. The HOT150 sheet says its thermostat adjusts but does not give the range.

What we checked but did not link

American Standard ASH-series dispensers. Several are sold by Amazon. We found no installation manual or spec sheet for them on American Standard’s site, only Amazon listing text. Our picks need a maker document for every spec, so we left them out.

Other InSinkErator styles. InSinkErator sells other faucet styles too; its Amazon listing for the Invite Contour system also lists a 2/3-gallon stainless steel tank. The HOT250 documents give a 3-year in-home warranty, so we picked it. If your old InSinkErator tank has failed but the faucet is fine, InSinkErator sells the tank alone; its HWT200 manual covers that swap.

How to Choose an Instant Hot Water Dispenser

Dispenser or under-sink water heater?

These are two different products. A dispenser has its own faucet and a tank that holds water near boiling for drinks and cooking. InSinkErator says the tank is not pressurized and must only feed its own faucet. Moen says its tank is not meant to give a continuous flow of hot water. Plumber’s note: an under-sink water heater, also called a point-of-use heater, is a mini-tank or tankless unit that feeds the regular hot side of your faucet. It fixes a far sink that takes minutes to run warm. A dispenser will not warm your main faucet at all. For that job, see our under-sink water heater picks.

Hot only or hot and cold

A hot-only faucet has one handle and takes the least room. A hot and cold faucet, like the HOT250 HC model, adds a cold drinking water handle to the same spout. InSinkErator makes that cold side “filter-ready” for its own filter, sold separately. If you already have a separate filter faucet, or you do not want a cartridge to change, hot only is simpler.

Temperature and heater size

InSinkErator’s HOT250 goes from 160 to 210°F, and Moen’s IH2300 from 140 to 190°F. InSinkErator’s troubleshooting notes that water boils at lower temperatures at higher altitude, so a high setting can make the tank spit. The Moen tank has a 1,500 W element and the InSinkErator tanks 750 W. InSinkErator lists up to 60 cups per hour for the HOT150, and Moen’s install guide gives the same 60-cup figure for the IH2300, but neither says what size cup it counts. Plumber’s note: the wattage is the firmer number to compare, since twice the watts heats a refill about twice as fast.

Faucet height, width and backsplash room

Faucet height matters under a low window or shelf. The HOT250 faucet is 8.21 in. tall, and the HOT150 is 6-1/4 in. The hot-only HOT250 is 2.97 in. wide and the hot and cold model is 3.96 in. The HOT150 sheet wants at least 2 in. from the center of the hole to the backsplash. The HOT250 handles move forward so they do not hit the backsplash, per InSinkErator.

Warranty

InSinkErator gives the HOT250 a 3-year in-home warranty covering parts and labor, and the HOT150 1 year of parts and in-home service. Moen gives the IH2300 tank 1 year and the Sip faucet a limited lifetime warranty. InSinkErator’s manual says an instant hot tank, like any water heater, has a limited life and will eventually fail. Plumber’s note: that makes the tank warranty the one to compare.

I send an occasional note when a new guide goes up — repairs worth doing yourself, and the parts that actually last. No spam, no course funnel; written by a licensed Georgia plumber.

Before You Buy

1. Look for an outlet under the sink. InSinkErator requires a grounded GFCI outlet with power on all the time, not one switched with the disposal. Moen wants a grounded outlet no switch controls. Both put the tank within 30 in. of it.
2. Find the hole. InSinkErator says an existing sprayer hole can work. You need 1-3/8 in. for InSinkErator, or at least 1-1/4 in. for Moen. See our kitchen faucet hole size guide.
3. Measure the counter and the backsplash. Counter thickness limits run from 2 in. (HOT150) to 2-1/2 in. (Moen Sip) and 2-9/16 in. (HOT250 manual).
4. Check the cold shut-off valve. Both makers tee off the cold valve under the sink. If it is old or will not close all the way, replace it first.
5. Check your water pressure. InSinkErator says 15 to 80 psi for the HOT250 and 30 to 80 psi for the HOT150, and not to install above 80 psi. A water pressure gauge on a hose bib tells you.
6. Check cabinet space. The InSinkErator tank is about 10-7/8 in. tall, 6-3/4 in. long and 6-1/8 in. wide, and must be within 16 in. of the faucet. Moen wants 4 in. of air space on the sides and top of its tank.

Installing an Instant Hot Water Dispenser

The sink hole

InSinkErator’s manual says you can use the sprayer hole if you have one. Remove the sprayer and cap the old spray hose line with a 1/8 in. plug or a 1/4 in. cap, and a basin wrench helps. To cut a new hole in a stainless sink, it calls for a 1-3/8 to 1-1/2 in. hole saw made for stainless steel, or a hole punch. For any other surface, it says to consult a professional. Plumber’s note: quartz and granite need a diamond core bit, water to cool it and a steady hand, so that is a job for the counter shop or a plumber.

Water line connection

Both makers connect to the cold water line under the sink, through a tee at the cold angle stop. InSinkErator calls for a 1/4 x 3/8 in. T fitting or an angle stop valve, not included. It recommends a dedicated shut-off valve on the cold line to the system. Moen’s install guide uses a 3/8 in. compression tee and lists it as not included (the Amazon tank listing says install parts are included, so check the box): the tee goes on the cold angle valve, the kitchen faucet’s cold supply line goes on one side of it, and the tank’s cold inlet line on the other. Moen says to shut the water off first and open the faucet to relieve the pressure. InSinkErator’s tank manual says to attach to the cold supply only, never a hot water line. Moen says not to use pipe sealing compounds. InSinkErator says not to install where water hammer happens unless you add a water hammer arrester. Plumber’s note: neither maker’s instructions we read use a self-piercing saddle valve; both use a tee, and that is the connection to make. See why inspectors fail saddle valves, and our picks for under-sink shut-off valves, braided supply lines and water hammer arrestors.

Tubing between the faucet and the tank

The InSinkErator faucet has several tubes, including a water inlet, a tank outlet and a vent. InSinkErator says the tank is not pressurized. It says not to close the vent tube, and not to connect any other faucet or valve to the tank. Moen’s tank is also unpressurized, which is why Moen says a short delay before water flows is normal. InSinkErator gives a minimum bend of 1 in. for 1/4 in. tubing and 1-1/4 in. for 3/8 in. tubing. It says to keep the tube straight for 1 in. above the quick connection at the tank, and to push each tube all the way into its fitting. InSinkErator also warns that water must not sit in the outlet tube. Shorten the tube so it drains back into the tank. Moen says to keep its hoses and tubes free of kinks and twists.

Power under the sink

InSinkErator requires a standard grounded GFCI outlet under the sink with power supplied all the time. It must be fused, on a 15 amp fuse or breaker at 120 volts, and not controlled by the same wall switch as the disposal unless you use InSinkErator’s SinkTop Switch. Moen requires a grounded 120 volt supply on a 15 or 20 amp fused circuit, recommends a separate circuit for the tank alone, and says not to use an outlet controlled by a switch. Both makers put the tank within 30 in. of the outlet, and both say no extension cord and no plug adapter. If the plug does not fit, both say to have a qualified electrician install a proper outlet. Plumber’s note: many sink cabinets have only the switched outlet for the garbage disposal. That one will not do, so plan for an electrician to add an always-on GFCI outlet.

Fill it before you plug it in

Both makers say to fill the tank before the power goes on. InSinkErator says not to plug in until the installation is done, then to open the handle until water flows and let it run 3 minutes to flush the lines. Its quick guide says at least 2 minutes. It then takes 16 to 20 minutes to heat, and gurgling or hissing during the first heat is normal. Moen says to turn the thermostat to off and fill the tank before plugging it in. If a Moen tank is powered while empty, its self-resetting fuse cuts the heater in about a minute. Check every connection for leaks before you close the cabinet.

Safety

• Scalding: InSinkErator warns the water can reach 210°F and burn instantly. Moen says not to let children use it.
• Leaks: InSinkErator says to use a drain pan, piped to a drain or fitted with a water leak detector, wherever a leak could cause damage, and to check the tank regularly for leaks and corrosion.
• Fire: InSinkErator says not to store rags, paper, aerosol cans or flammable liquids near the tank.
• Drilling: InSinkErator warns not to drill where wiring or water pipes could be in the path when you mount the tank bracket.

Care, Filters and Freezing

To change the temperature, turn the dial on the tank. InSinkErator says to then run the faucet 20 seconds and wait 5 to 7 minutes. If the tank boils and spits, turn the dial down. With InSinkErator’s filter, change the cartridge every 6 months. Moen offers its F9800 carbon filter, and Moen says the Sip faucet needs an additional hole for it. Clean the faucet with mild cleaners only; InSinkErator says acid, abrasive or solvent cleaners damage the plastic parts and void the warranty. If rusty water suddenly shows up, InSinkErator says it may mean the tank needs service or replacement.

InSinkErator says to drain the tank and tubing, and remove the filter cartridge, when it may drop below 40°F or the unit will sit unused for a long time. Its steps: unplug the tank, run the hot faucet until the water is cool, shut off the cold supply, then unhook the tank and drain it into the sink. Moen says to drain its tank before freezing weather or a long time away: unplug it, turn the dial to off, run the faucet until the water is cold, and drain into a 3-quart container from the plug at the bottom. Plumber’s note: never drain a tank that is still hot, and draining matters most in a cabin or a kitchen on an outside wall.

When to call a pro

Call an electrician if the tank’s plug does not fit a grounded outlet under the sink, both makers say. Plumber’s note: the same goes if the only outlet there is the switched one for the disposal. Consult a professional before drilling stone or any surface other than stainless steel, InSinkErator says. Plumber’s note: call a plumber if the cold shut-off valve will not close or leaks when you turn it, or if your supply is soldered copper with no valve. Adding a new valve first is the right fix.

FAQ

Is an instant hot water dispenser the same as an under-sink water heater?

No. A dispenser has its own small faucet and a tank that keeps water near boiling, about 200°F on InSinkErator’s factory setting, for tea, oatmeal and cleanup. Moen says its tank is not meant to give a continuous flow of hot water. An under-sink (point-of-use) water heater feeds the hot side of your regular faucet so a far sink runs warm sooner. If that is your problem, see our under-sink water heater picks.

Does an instant hot water dispenser need its own outlet?

It needs an outlet under the sink. InSinkErator requires a grounded GFCI outlet that has power all the time, on a 15 amp fuse or breaker, and not on the same wall switch as the disposal. Moen asks for a grounded 120 volt outlet on a 15 or 20 amp circuit that no switch controls, and recommends a separate circuit. Both say the tank must be within 30 in. of the outlet and not to use an extension cord.

What size hole does an instant hot water dispenser need?

InSinkErator lists a standard 1-3/8 in. hole, and its manual allows 1-3/8 to 1-1/2 in. Moen’s Sip faucet needs a hole at least 1-1/4 in. across. InSinkErator says you can use the sink’s sprayer hole if you cap the old sprayer line. For stone or other surfaces, it says to consult a professional before drilling.

How hot does the water get?

InSinkErator’s HOT250 thermostat adjusts from 160 to 210°F and comes set near 200°F. Moen’s IH2300 dial runs from 140 to 190°F, and Moen says the water comes out at about 190°F. Both makers warn that the water can scald. InSinkErator says it takes 16 to 20 minutes to heat after the first fill.

How does a hot water dispenser connect to the water line?

To the cold water line, through a tee at the cold shut-off valve under the sink. InSinkErator calls for a 1/4 x 3/8 in. T fitting or an angle stop valve, not included, and recommends a dedicated shut-off for the dispenser. Moen uses a 3/8 in. compression tee, also not included, between the angle valve and your kitchen faucet’s cold supply line. Neither connects to the hot line.

Why Trust Plumbing Picks

Plumbing Picks is written by a licensed Georgia journeyman plumber. Every spec here comes from the maker documents listed below or the Amazon listings we link; nothing comes from hands-on testing. On September 29, 2026, every linked listing was sold by Amazon.com and in stock. If you buy through a link we may earn a commission at no extra cost to you. Nobody pays to be included here. More on who writes this and how we pick.

Sources

• InSinkErator: HOT250 hot-only product page, HOT250 hot-only job specifications, HOT250 Installation, Care & Use manual (English, Spanish and French; includes the warranty)
• InSinkErator: HOT250 hot and cold product page, HOT250 hot and cold job specifications
• InSinkErator: Invite HOT150 product page, HOT150 submittal sheet, quick install guide (all InSinkErator dispensers), HWT200 replacement tank manual
• Moen: IH2300 Instant Hot tank product page, IH2300 specification sheet, Sip Transitional faucet product page, Sip Transitional IH7620 specification sheet, Sip faucet and IH2300 tank installation guide INS14046B (includes both warranties)
• Amazon listings for the InSinkErator HOT250 (hot only and hot and cold), InSinkErator HOT150, Moen IH2300 tank and Moen Sip IH7620SRS faucet (linked above), plus the American Standard ASH-series listings we checked but did not link

Bottom Line

An instant hot water dispenser is a small faucet and a near-boiling tank for drinks and cooking, not a water heater for your main faucet. The InSinkErator HOT250 is the pick for most kitchens, the HC250 adds a cold drinking water tap that takes an optional filter, the Moen IH2300 and Sip faucet add a two-step handle, and the HOT150 has the shortest faucet. Before you buy, confirm an always-on grounded outlet under the sink, a spare 1-1/4 to 1-3/8 in. hole, and a working cold shut-off valve to tee into.