For most CPAP users, buy the Megahome MH943TWS. It makes a gallon in 5.5 hours, about 10 full ResMed tub fills. Want a stainless outside? Get the H2o Labs 300SS. Can’t lift a full tank? The H2o Labs Model 200 has a lift-out reservoir.
Top pick: Megahome MH943TWS$275.00 at AmazonPrice as of Oct 24, 2026, 5:30 AM EDT
Three distillers, each for a different kind of user. Each was the genuine brand, new and in stock on Amazon when I last checked, on Oct 21. Prices come from Amazon and show the time they were read.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
How many nights one gallon covers
This is the number most CPAP pages skip. A distiller makes one gallon per run, and your tub holds a set amount. Here’s how far a gallon goes in the two most common machines.
A US gallon is 3,785 mL. Tub sizes from the ResMed AirSense 11 user guide and the Philips DreamStation 2 user manual, read Oct 19, 2026. The math is mine.
Both makers tell you to empty the tub every day and refill it, so a full fill each night is the safe number to plan on. That’s about 10 nights per gallon on an AirSense 11 and about 11 on a DreamStation 2.
My call: one distiller run every week covers one machine with room to spare. Two people on CPAP in one house need a run about every five days.
The pick for most CPAP users: Megahome MH943TWS
Best for most CPAP users
Megahome MH943TWS
Countertop water distiller with glass collection bottle
Not for well water, per Megahome, unless you get the 316 tank
Enamel steel outside, not stainless
1-year warranty
1 gal per 5.5 hUp to 16 L a day580 W, 120 V8 × 14¼ in.7.7 lb6 carbon packs in the box
Buy it if
You use a CPAP every night, you want water that only touches stainless steel and glass, and you’d like a US support team for parts.
Skip it if
Your water comes from a private well. Megahome’s manual says not to distill well, river or sea water unless you order the 316 stainless tank version.
The MH943TWS is the distiller I’d point most CPAP users to. Nutriteam, which sells and supports Megahome in the US, lists it as a 1 gallon countertop unit. The boil chamber, the dome on top and the cooling coils are all 304 stainless steel, and the outer shell is white enamel-coated steel.
For a CPAP, the part that touches the water matters most. Nutriteam says the water only touches stainless steel and glass. It drips through a porcelain-lined nozzle into a 1 gallon glass bottle with a polypropylene lid and handle. ResMed and Philips both ask for distilled water in their standard tubs.
It makes 1 gallon in 5.5 hours, per Nutriteam, and up to 16 liters a day if you run it back to back. The listing says it boils at 212°F. My call: start it after dinner and the bottle is full by bedtime.
Power is 580 W at 120 V, with a 565 W heater and a 15 W fan. Nutriteam says Megahome units are UL listed and use a thermal switch plus a thermal fuse to stop overheating. The unit is 8 in. wide, 14¼ in. tall and weighs 7.7 lb.
The box includes 6 activated charcoal packs, a 250 g jar of residue cleaner and the glass bottle. The listing calls the charcoal packs optional and says they’re for VOCs like chlorine that can boil off as vapor. If you’re on city water, use them. Nutriteam says 12 packs last about 360 gallons, about 30 gallons each.
Nutriteam backs it with a 1-year parts and labor warranty and offers support and repair parts after that. My call: buy it for nightly CPAP use. It was sold by Nutriteam, new and in stock when I checked.
A stainless steel body and a 5 hour run: H2o Labs 300SS
Best for a stainless steel exterior
H2o Labs 300SS
Stainless steel countertop water distiller with glass carafe
1 gal per 5 hUp to 4 gal a day580 W, 120 V8 × 14¼ in.7.7 lb565 W heater
Buy it if
You want a stainless steel outside, a carafe you can pour from with one handle, and the carbon pods and descaler in the box.
Skip it if
You’d rather buy from the US Megahome team or you don’t need the stainless finish. The Megahome is the safer default.
The 300SS is the pick if you want stainless steel on the outside too. H2o Labs’ manual covers the Model 300 and 300SS together, and its product page says they differ only in the exterior. The 300SS has a stainless steel body, and the steam chamber, dome and condensing coil are 304 stainless.
The specs match the Megahome closely. The manual lists 8 by 14¼ in., 7.7 lb, a 1 gallon boil chamber, 120 V and 580 W in total, with a 565 W heater per the listing. Output is about 1 gallon per 5 hours and up to 4 gallons a day, so it runs about half an hour shorter.
Water drips through a nozzle with a glass insert into a 1 gallon borosilicate glass carafe. H2o Labs says the plastics are food safe and BPA free, and the lid and handle are polypropylene. The carafe has two stainless straps and a handle, and the carafe manual says to lift it with both hands.
The box includes 6 carbon pods and a jar of cleaning crystals. The manual says not to drink the water from the first cycle, since new stainless can leave a faint taste. Use it to rinse the next carbon pod instead. My call: run two cycles before the first gallon goes in your tub.
The manual is careful about power. Don’t share the outlet with other high-wattage appliances, and avoid extension cords. Never lift the top while it’s running or for 30 minutes after. H2o Labs suggests running it at night so a full carafe waits for you in the morning.
H2o Labs gives it a full 1-year parts and labor warranty, with 2 and 3 year plans sold separately. My call: buy it if stainless steel matters to you. It was sold by Water Distillers Direct, new and in stock when I checked.
If lifting a full tank is hard: H2o Labs Model 200
1 gal per 5 h (approx.)Up to 4 gal a day600 W, 5 A11 × 10½ × 13 in.7¾ lb1 gal lift-out reservoir
Buy it if
Carrying a full gallon tank to the sink is hard for you, and you’re fine with food-grade plastic in the water path.
Skip it if
You want the water to touch only stainless steel and glass. The Megahome or the 300SS does that.
The Model 200 is for the CPAP user who’d rather not carry a full steel tank to the sink. Its 1 gallon tap water reservoir lifts off the base on its own, and you fill that at the faucet. H2o Labs’ product page says it’s built light for seniors and anyone who has trouble lifting.
Inside, it’s a different machine from the 300SS. The reservoir feeds a small boiling tray a little at a time, and the heating element sits right in that water. H2o Labs says distilled water starts dripping in about 5 minutes, and the manual puts a full gallon at about 5 hours.
The trade-off for a CPAP is the material. The manual lists an ABS body, heat-resistant food-grade plastic for the internal parts and a food-grade plastic carafe. The Megahome and the 300SS keep the water on stainless steel and glass. If that matters to you, buy one of those instead.
It guards itself well. Lift or tilt the main unit off its base and it shuts off. It won’t start with an empty reservoir, and it stops when the tray runs low. Two thermal cut-off fuses sit on the element, so the second one still cuts power if the first fails.
Day to day, upkeep is light. Rinse the tray after each run, or put it in the dishwasher. After every 10 gallons, soak the element and tray in white vinegar or cleaning crystals for a few hours. Swap the carbon pod after 30 gallons or 30 days, and the infrared anti-scale pad every 3 to 6 months.
Treat the first cycle as a rinse. The manual says not to drink it and to use it to rinse the carbon pod. My call: buy it if lifting is the problem and plastic in the water path isn’t. It was sold by Water Distillers Direct, new and in stock when I checked on Oct 21.
All three picks side by side
Every number here is from the maker’s manual, data sheet or US distributor. Scroll sideways on a phone. Prices are in each card and the picks above.
Green marks the better number in a column, and amber marks a trade-off. The H2o Labs time is the manual’s approximate figure; its manual also says a full gallon can take 5 to 6 hours.
Which water your CPAP tub takes
Not every tub needs distilled water. ResMed sells two tubs for the AirSense 11 and they take different water. Check the color of your tub’s thumb grip.
Machine and tub
How to tell
Water the maker asks for
Capacity
ResMed AirSense 11, HumidAir 11 Standard tub
White thumb grip, single patient
Distilled water only
380 mL maximum
ResMed AirSense 11, HumidAir 11 Cleanable tub
Grey thumb grip, multi patient
Drinking quality water
380 mL maximum
Philips DreamStation 2 humidifier tank
Removable tank on the machine
Room temperature distilled water only
325 mL at the recommended level
From the ResMed AirSense 11 user guide and the Philips DreamStation 2 user manual, read Oct 19, 2026. Other machines and older tubs have their own rules, so read your own manual.
Philips also says not to put any chemicals or additives in the water, since that can irritate your airway or damage the tank. ResMed says to take the tub out of the machine before you fill it, and to fill to the maximum mark and no higher.
My call: if you have the white-grip ResMed tub or a DreamStation 2, a distiller earns its spot on the counter.
How long a gallon takes and what it draws
The Megahome and the 300SS draw 580 W while they run, and the Model 200 is rated at 600 W. The longer the run, the more power each gallon uses. Here’s the math from the makers’ own numbers.
From Nutriteam’s MH943TWS product page and the H2o Labs Model 300 and 300SS and Model 200 manuals.
Distiller
Rated draw
Hours per gallon
Most energy per gallon
Megahome MH943TWS
580 W
5.5
About 3.2 kWh
H2o Labs 300SS
580 W
About 5
About 2.9 kWh
H2o Labs Model 200
600 W
About 5
About 3.0 kWh
My arithmetic: rated watts times hours, divided by 1,000. It’s a ceiling, since all three units shut off on their own at the end of the run. Multiply by the rate on your power bill to get your cost per gallon.
A 580 W load on a 120 V circuit draws a little under 5 amps. H2o Labs also says not to share the outlet with other high-wattage appliances. My call: give it a counter outlet of its own, and run it at night when the kitchen is quiet.
A distiller vs bottled jugs and other options
Google’s top results for this search mix forum threads, distiller stores and a pitcher sold for CPAP use. Here’s how the common ways to get CPAP water compare.
Option
Makes distilled water
Fits a distilled-only tub
What to know
Countertop distiller
Yes
Yes
One gallon per 5 to 6 hour run
Store jugs labeled distilled
Yes
Yes
Trips to the store; jugs to recycle
Filter or ion pitcher
No
Not by the label
Filtered water isn’t distilled water
Reverse osmosis under the sink
No
Not by the label
It’s a filter, not distillation
Boiled tap water
No
No
Boiling leaves the minerals in
The CPAP column is my reading of the ResMed and Philips manuals, which say distilled water for their standard tubs. Ask your equipment supplier if you want to use anything else.
Boiling is the one people get wrong most. It kills germs, but the minerals stay in the pot. Distilling boils the water and then catches only the steam, so the minerals stay behind in the chamber. Our distiller vs reverse osmosis page covers the filter side in detail.
Cleaning the CPAP tub, per the makers
Distilled water keeps mineral crust out of the tub, but it doesn’t replace cleaning. Here’s what ResMed and Philips ask for.
Task
ResMed AirSense 11
Philips DreamStation 2
Every day
Empty the tub, wipe it with a clean cloth, let it dry, refill
Empty and hand wash the tank
Every week
Wash in mild dish soap, or 1 part vinegar to 9 parts water
Top rack of the dishwasher, or soap; then 70% isopropyl alcohol for 5 minutes
Rinse
Rinse well with water
Rinse each part 1 minute in drinking water
Hot water limit
Not above 131°F (55°C)
Warm water
White powder in the tub
1 part vinegar to 9 parts water, then rinse
Not covered
Replace the tub
Leaking, cracked, cloudy or pitted
Signs of wear or damage
From the ResMed AirSense 11 user guide and the Philips DreamStation 2 user manual. ResMed also lists a 6 month design life for the Standard tub.
The white powder ResMed mentions is mineral scale, the thing distilled water is meant to prevent. If it shows up in a distilled-only tub, the water isn’t as clean as it should be. My call: check the distiller’s carbon pod and clean the boil chamber before you blame the tub.
Keeping the distiller clean
A distiller is simple, but the boil chamber collects everything it takes out of your water. These are the upkeep steps in the H2o Labs 300SS manual, and the Megahome’s printed specs match it closely. The Model 200 has its own schedule, in its card.
1
Skip the first gallon
H2o Labs says not to drink water from the first cycle. Use it to rinse the next carbon pod or water plants.
2
Clean after each run
Once it has cooled 30 minutes, unplug it, pour out what’s left and wipe the chamber. No abrasive pads.
3
Descale when crust builds
Soak half a cup of white vinegar for about an hour, or use the cleaning crystals for stubborn scale.
4
Change the carbon
Replace the pod every 30 to 60 days, or when you notice a taste or smell.
5
Dust the coil
When dust builds up on the condensing coil, vacuum it or blow it out through the slots in the cover.
The manual also says the boil chamber has normal welding spots on the bottom, and not to try to remove them. The Megahome ships with its own residue cleaner, and Nutriteam sells parts and gives support after the warranty. My call: rinse the chamber every morning when you take the bottle out.
The two supplies worth keeping on hand
Carbon and a descaler keep a distiller running well. Neither one makes water, so they sit here rather than in the picks.
Supply
What it’s for
Fits
How often
H2o Labs Mega Pods, 6 pack
VOCs like chlorine that boil off with the steam
H2o Labs Models 100, 100SS, 300 and 300SS, and other nozzle-type units
Every 30 to 60 days
H2o Labs Cleaning Crystals, 16 oz
Crust a vinegar soak won’t lift
Distiller boil chambers, per the listing
When scale builds; 1½ tbsp per gallon
Megahome charcoal packs
Same job as the pods, in a flat sachet
Megahome units
12 packs per about 360 gallons, per Nutriteam
On chlorinated city water, I’d keep a 6 pack of H2o Labs Mega Pods next to a 300SS. They drop into the nozzle with no folding. The listing doesn’t name the Model 200, whose pod mounts on its carafe, so match the pod to your model. H2o Labs says to skip carbon when the water is for a dental autoclave.
On hard water, a jar of H2o Labs Cleaning Crystals handles crust that vinegar leaves behind. The data sheet lists citric acid and calls it an eye irritant. Run the cleaning boil with the top off, so no acid steam reaches your carafe.
Safety rules from the manuals
Each distiller boils water for hours under a hot lid. The makers print a short list of rules, and the CPAP makers add a few of their own.
Its own outlet
H2o Labs says not to share it with other high-wattage appliances.
Room temperature water
Philips and ResMed both say to fill the tub with room temperature water. Let the gallon cool first.
Let the CPAP cool
Philips says to wait about 15 minutes after therapy before you take the tank out.
Top stays on
H2o Labs says never lift it while running or for 30 minutes after.
Skip extension cords
H2o Labs says avoid them unless you have no other option.
Nothing added
Philips says no chemicals or additives in the tank water.
I searched the CPSC recall database for Megahome, Nutriteam and H2o Labs and found no recalls. H2o Labs mentions the noise and heat of a run as a reason to run it at night. My call: set it on a counter with open space above it, away from the CPAP itself.
Storing distilled water for the week
One run makes a gallon, and you’ll use about a tenth of it each night. How you store the rest matters.
Step
Why
Keep it in the glass bottle or carafe it dripped into
Both makers built the path so the water touches only steel and glass
Keep the lid on between fills
Open water picks up dust and whatever is in the air
Let it cool to room temperature before filling the tub
Philips and ResMed both say room temperature
Start a new run when the bottle is about half empty
H2o Labs suggests this, so you always have a reserve
Neither CPAP maker prints how long stored distilled water stays good. My call: use each gallon within a week or so and wash the bottle between runs. If you travel, the AirSense 11 guide says to empty the tub and pack it on its own.
Where the listings and the makers disagree
I check every listing against the maker’s documents. These didn’t line up, and here’s what I went with.
Product
One source says
Another says
I used
H2o Labs 300SS run time
Spec table: 1 gallon per 5 hours
Same manual: 5 to 6 hours
About 5 hours, with the range noted
H2o Labs 300SS output
Spec table: up to 4 gal a day
Megahome: over 4 gal a day
Each maker’s own figure
Megahome UL claim
Listing: one of the only UL distillers
Nutriteam page: the only UL distillers
UL listed, with no ranking
Megahome warranty
Nutriteam: 1 year parts and labor
Listing: 1 year against defects
1 year parts and labor
H2o Labs Model 200 power and size
Product page spec box: 580 W, 8 × 14¼ in.
Model 200 manual: 600 W, 11 × 10½ × 13 in.
The manual’s figures
VEVOR YMK40101
US listing: FDA certification
Only a 220 V German manual found
Dropped it
The Megahome and the 300SS print nearly identical numbers: the same size, weight, chamber and wattage. Nothing in either maker’s documents shows one making purer water, so the differences that matter are the finish, the run time and who sells it.
How to choose in five questions
Question
If yes
If no
Does your tub need distilled water?
Keep going
Your tub may take drinking water; check the manual
Is carrying a full tank to the sink hard for you?
H2o Labs Model 200
Keep going
Do you want a stainless steel outside?
H2o Labs 300SS
Megahome MH943TWS
Does your water come from a city system with chlorine?
Use carbon packs or Mega Pods each run
Test well water first; carbon may be needed
Do you see crust in the boil chamber after a week?
Add the Cleaning Crystals
Vinegar and a rinse will do
Most people land on the Megahome, with its own charcoal packs and residue cleaner in the box. If you own a 300SS, keep a 6 pack of Mega Pods and a jar of crystals on hand. For drinking water for the whole family, our best home water distillers page compares more units.
Questions people ask
What is the best water distiller for a CPAP?
For most CPAP users, the Megahome MH943TWS. It makes a gallon in 5.5 hours, the water touches only stainless steel and glass, and Nutriteam supports it in the US. For a stainless steel outside, the H2o Labs 300SS. If lifting a full tank is hard, the H2o Labs Model 200.
Do I really need distilled water for my CPAP?
It depends on the tub. The ResMed HumidAir 11 Standard tub and the Philips DreamStation 2 tank both call for distilled water. The ResMed HumidAir 11 Cleanable tub, with a grey grip, takes drinking quality water. Check your own manual.
Can I make my own distilled water for my CPAP machine?
Yes, with a countertop distiller. It boils the water and catches the steam, leaving minerals behind. Boiling water in a pot doesn’t do this, because the minerals stay in the pot.
How long does a water distiller take to make a gallon?
About 5.5 hours for the Megahome MH943TWS and about 5 hours for the H2o Labs 300SS and Model 200, per their makers. H2o Labs’ manual says a full gallon can take 5 to 6 hours.
How many nights does a gallon of distilled water last on a CPAP?
About 10 full fills on a ResMed AirSense 11, which holds 380 mL, and about 11 on a Philips DreamStation 2 at 325 mL. Both makers say to empty and refill the tub every day.
What are the downsides of using a water distiller?
Time and upkeep. A run takes 5 to 6 hours at 580 W, and the boil chamber needs cleaning after each run. Hard water leaves scale that needs vinegar or a citric acid cleaner.
Should I use the carbon filter for CPAP water?
If your water is chlorinated, yes. The Megahome listing says the charcoal packs catch VOCs like chlorine that boil off with the steam. H2o Labs says to change its pods every 30 to 60 days.
Is store-bought distilled water the same as a home distiller’s?
Both are distilled. A home distiller saves trips to the store and plastic jugs. Store jugs make sense if you only need water for travel or a short time.
Can I use filtered or reverse osmosis water in my CPAP?
Not where the manual says distilled only. Filtered and reverse osmosis water aren’t distilled. If your tub calls for distilled water, ask your equipment supplier before you use anything else.
How do I clean a CPAP water tub?
ResMed says to empty and wipe the tub daily, and wash it weekly in mild soap or 1 part vinegar to 9 parts water. Philips says hand wash daily and disinfect weekly in 70% isopropyl alcohol for 5 minutes.
How I picked these
Why trust me
I’m Isaac Daniels, a licensed journeyman plumber in Georgia (license #JP507711). Every spec here comes from the makers’ manuals, data sheets and US distributor pages, and from the ResMed and Philips manuals, read the same day.
How I pick
Only genuine brand products, new and in stock on Amazon, checked through Amazon’s Creators API on Oct 19 and again on Oct 21. The seller is named on each card.
Offers that were low on stock, back-ordered or unavailable were left out. That dropped the Waterwise 3200, a Durastill unit and a Megahome model with a plastic bottle on Oct 19.
Distillers I couldn’t match to a US maker manual were skipped, including VEVOR and CO-Z listings.
Specs from each maker’s own documents first, then the listing, and listing-only claims are labeled.
Each card’s spec score uses the same five checks, shown in the tables below. Carbon pods and a descaler are supplies, not distillers, so they sit in their own section.
CPSC recall search for Megahome, Nutriteam, H2o Labs and Waterwise: no recalls. The only distiller recall I found was a West Bend unit in 1999.
The spec score, check by check
Each check scores 0 to 10 and counts one fifth. It rewards a steel and glass water path, a shorter run, easy filling, the supplies in the box and a printed warranty. It’s our score from the makers’ manuals and pages, not a customer rating or a water test.
Check (weight)
How it’s scored
Water path (⅕)
10 when the made water touches only stainless steel and glass; 7 when the tray, internals or carafe are food-grade plastic
Time per gallon (⅕)
Maker’s figure: 10 for about 5 hours or less; 9 for 5.5 hours
Filling (⅕)
10 with a lift-out reservoir you fill at the sink; 8 when you fill the boil chamber itself
In the box (⅕)
10 with carbon and a descaling cleaner in the box; 8 with carbon only
Warranty (⅕)
10 for 1 year parts and labor printed by the maker or its US seller; 5 when the papers I read don’t print a term
Total
Average of the checks, to one decimal
Pick
Water path
Time per gallon
Filling
In the box
Warranty
Score
Megahome MH943TWS
10
9
8
10
10
9.4
H2o Labs 300SS
10
10
8
10
10
9.6
H2o Labs Model 200
7
10
10
8
5
8.0
Sources
Nutriteam MH943TWS product page (304 stainless chamber, dome and coils, 1 gallon per 5.5 hours, 16 L a day, 580 W, heater and fan watts, size, weight, box contents, UL listing, thermal switch and fuse, 1-year parts and labor warranty, charcoal pack life): nutriteam.com.
H2o Labs Models 300 and 300SS instruction manual (size, weight, capacities, output, 580 W, outlet and extension cord rules, 30 minute top rule, first cycle, cleaning, vinegar, carbon pod change, coil dusting, dental autoclave note): h2olabs.com.
H2o Labs Model 300CG glass carafe instructions (handling, assembly) and 300SS product page (stainless exterior, 565 W heater, UL listing, 1-year parts and labor warranty): h2olabs.com.
ResMed AirSense 11 user guide (HumidAir 11 Standard and Cleanable tubs, water type, 380 mL capacity, daily and weekly cleaning, vinegar ratio, 131°F limit, tub replacement, design life, travel): resmed.com.
Philips DreamStation 2 user manual (distilled water only, no additives, 325 mL capacity, 15 minute cool-down, daily washing, weekly disinfection with 70% isopropyl alcohol): philips.com.
Megahome distiller instruction manual for the MH943T and MH943S series (well, river and sea water limit; 316 stainless tank version): Megahome, via Nutriteam.
H2o Labs Model 200 instruction manual, 12/12/15 (reservoir, boiling tray, materials, shut-offs, thermal fuses, first cycle, cleaning every 10 gallons, carbon pod and anti-scale pad schedule, size, weight, 600 W, 5 A, output) and Model 200 product page (built light for people who have trouble lifting, first water in about 5 minutes, spec box): h2olabs.com, read Oct 19, 2026.
University of Nebraska–Lincoln Extension, NebGuide G1493, Drinking Water Treatment: Distillation (solvents that boil with the water, testing first): extensionpubs.unl.edu, read Oct 20, 2026.
CPSC recall search for Megahome, Nutriteam, H2o Labs, Waterwise and VEVOR: saferproducts.gov, Oct 19, 2026.
Amazon listings for B00026F9F8, B010GLSB6C, B005QDEAMK, B07GZ2ZPC9 and B078YHL5L8 (titles, features, sellers, stock): read through the Creators API, Oct 19 and Oct 21, 2026.
