How to make ice at home in bulk

Three ways to source ice for a cold plunge, in ascending order of cost and descending order of hassle: pick up 20-pound bags from a grocery store or gas station (roughly 15 to 25 cents per pound, plus a 10 to 15 minute drive), fill silicone moulds in your existing home freezer (effectively free after the trays, capped at a few pounds per day depending on freezer size), or plug in a countertop ice maker ($100 to $200 upfront, in the range of 20 to 26 pounds a day if you keep feeding it water). None of them beats the grocery bag on cost per pound. Two of them beat it on the specific misery of driving to the shop at five in the morning.

Your first bag of ice from the corner store costs about $3 and takes fifteen minutes. Your fiftieth still costs $3, and by then it feels like $30 by the time you have loaded the freezer, unloaded the car, and remembered on a Tuesday to grab some for a Wednesday plunge. This guide is about the three ways home practitioners actually solve that problem, and the specific case for skipping all of them.

What you'll need

The shopping list per method, with the price ranges:

Method 1 (grocery bags): a punch card at your nearest convenience store, an insulated cooler for the drive home, and some tolerance for plastic bags.

Method 2 (freezer moulds): a set of large-block silicone ice moulds ($10 to $25 for a tray that makes eight to twelve fist-sized cubes), a lidded plastic bin to hold finished blocks, and some freezer shelf space.

Method 3 (countertop ice maker): a portable bullet-shape ice maker ($100 to $200 for a home unit), about two square feet of counter near a sink, and a jug for water refills.

That is the whole capital outlay. Method 1 is a repeated $3 to $5. Method 2 is a one-time $25 plus a small silent contribution to your electricity bill. Method 3 is $150 upfront, then a handful of cents in electricity per plunge session.

Method 1: The grocery bag baseline

A 20-pound bag of ice runs $3 to $5 at most US grocery chains and convenience stores. On a per-pound basis this is unbeatable. If your plunge cadence is once or twice a week and the shop is close, this method is your answer and the rest of this article is optional reading.

The catch is the logistics. A bag melts about 10 percent on the drive home in warm weather, faster with a hot car and no cooler. Storage requires either running to the store before every plunge, or dedicating serious freezer space to hold two or three bags between runs. And popping to the shop for ice is the specific errand that becomes a plunge-cadence killer the first time you skip a scheduled session because the shop was closed or you simply forgot.

How much ice you actually need per session is a separate question, and the answer varies enormously by tub size and ambient temperature. The summer ice math guide covers the exact arithmetic. For a 100-gallon stock tank in summer heat, roughly one bag per session with a cover on, two without.

Method 2: Silicone moulds in your existing freezer

A silicone mould that makes eight to twelve large ice blocks costs around $15. Fill it, freeze it overnight, tip the blocks into a plastic bin in your freezer, refill the mould, repeat. After a week of daily filling you have a working ice reservoir that never requires a shop run.

Production ceiling is your freezer, not the mould. A standard home freezer running two mould trays in rotation produces roughly six pounds of usable ice per twenty-four hours, plus or minus a couple of pounds depending on freezer efficiency and how often you open the door. A dedicated chest freezer does more, at the cost of running a whole second appliance. Categorising this alongside your other cold plunge accessories helps: it is a passive setup that runs itself once you have committed the shelf space.

Method 3: The countertop ice maker

A countertop bullet ice maker is a small compressor-driven machine that pulls water from a reservoir, chills a set of metal fingers dipped into that water, and drops the resulting hollow ice bullets into a basket every seven to twelve minutes. It does not freeze water solid the way your kitchen freezer does. The bullets are hollow and slightly softer, which for cold-plunge purposes matters less than you might think (they still cool water; they just melt into it faster).

A typical home unit is rated around 130 to 150 watts on the manufacturer plate and produces around 26 pounds of ice per twenty-four hours according to the same plate. In practice you get more like 20 pounds of usable ice if you actually keep the reservoir topped up. The basket holds two to three pounds and has no freezer of its own, so once the basket fills the machine pauses. Left alone unmonitored, you get about four hours of active production per full water reservoir before it stops needing you.

Electricity math: at 130 watts running two hours per plunge session, that is roughly a quarter of a kilowatt-hour, or about four cents at US average grid rates. Even at three sessions a week the ice maker's contribution to your power bill is a rounding error. The bigger cost is the counter space and the noise. These units are about the size of a large countertop microwave and run at about the volume of a dishwasher when active. If you have already thought about what you pay for at each tub tier, factor the countertop footprint in as part of the same category of ongoing cost.

The cost and time math, side by side

For the reader who wants the numbers together, three points of comparison across the three methods:

Cost per pound of ice: grocery bags are 15 to 25 cents a pound depending on local prices. Silicone moulds cost about half a cent to a cent per pound in electricity, effectively free after the tray purchase. Countertop ice makers work out to 3 to 5 cents per pound in electricity.

Time per session's-worth of ice: the grocery bag run is 10 to 15 minutes of active driving. Silicone moulds require zero active time but roughly 24 hours of planning ahead per tray. The countertop maker runs unattended for four to six hours plus one water refill halfway through.

Freezer space required: grocery bags eat about a cubic foot each. A silicone-mould workflow needs enough shelf room for the trays plus a bin for finished blocks, roughly 2 cubic feet. The countertop machine's basket sits on the counter and touches your freezer zero times.

Common mistakes

Freezer already full. The most common failure of the silicone-mould setup is packing the freezer with existing food and then trying to also produce a rotating pool of plunge ice. The freezer compressor cannot keep up, everything drifts a couple of degrees warmer, and the mould trays take twice as long to freeze. If your freezer is at 80 percent capacity before you start this experiment, the countertop ice maker earns its keep instead.

Portable ice maker in a hot corner. Ice makers work by dumping heat into the air around them. Putting one in a poorly-ventilated cabinet, or on the counter next to the oven, kneecaps its production rate by half. Give it two feet of clearance and a room under 78°F ambient.

Forgetting the shop run. The most reliable failure mode of the grocery-bag method is not remembering to make the run before an evening plunge. Set a phone reminder, or shift the ice run to a fixed weekly errand rather than an on-demand one.

Ice-maker bullets melting fast. The hollow bullets from a countertop machine have about 30 percent more surface area than a solid block of equivalent mass, so they melt into your tub water faster. This is not a problem, it is a feature: the ice does its cooling on a shorter timeline and gets out of the way. If you want the ice to sit dramatically on the surface for atmosphere, use silicone-mould blocks or grocery-bag chunks.

Which method fits your setup

Once-a-week plunger, small tub, near a store: the grocery-bag fit. Do not overcomplicate a simple thing.

Daily or near-daily plunger, freezer space available: the silicone-mould fit. Buy two trays so one is always freezing while the other holds finished blocks, and pick up a plastic bin large enough to hold three days' worth.

Three-times-a-week plunger, small kitchen, hates errands: the countertop ice-maker fit. Position it near the sink, run it during dinner prep, and treat the water refill as part of your evening routine.

Apartment dweller with no counter space: probably grocery bags for now, or a small silicone tray if you can spare a few inches of freezer shelf. The countertop machines eat more counter than most rented kitchens can spare for a piece of gear that runs a few hours a day.