For a beginner drying occasional surplus fruit and vegetables, 5 trays at around 250W is a reasonable starting point, and 6 trays at around 350 to 550W suits regular gluts. These are our rules of thumb, as we found no independent source that recommends a tray number or wattage for beginners. In our view, the drying area is a better yardstick than tray count. The National Center for Home Food Preservation says 12 square feet (about 11,000 square centimetres) of drying space dries about a US half-bushel of produce.[1] Choose a range of about 40 to 70°C, which covers the 54, 60 and 68°C figures that sources give,[2][3] and work out running cost from watts, hours and your pence per kWh.
- Trays: Compare tray size as well as tray count, because tray area decides how much fits in one batch.
- Watts: Wattage is the power rating, so it shows roughly the most electricity the machine can use in an hour, not how well food dries.
- Other features: In our view, a timer, a storage plan and storage space often decide whether the dehydrator gets used.
What Do Trays and Watts Actually Tell You?
A food dehydrator removes moisture from food to aid its preservation, using a heating element, fans and vents to direct hot air over the food.[2]
- Trays: The trays hold the food, so their number and size set how much fits in a batch. The National Center for Home Food Preservation names limited capacity as a dehydrator’s major disadvantage.[1]
- Watts: This is the electrical power rating. Energy used is power multiplied by time,[4] so wattage sets the most a machine can cost to run each hour. Wikipedia describes most modern dehydrators as low-power but gives no wattage figure.[2]
Which Five Factors Separate One Food Dehydrator From Another?
While choosing a food dehydrator you have to keep in mind following things:
- Drying area: Multiply the listed tray length by width and by the number of trays. This is rough, because the usable mesh area is smaller than the tray footprint.
- Wattage: Compare watts only between machines of similar drying area, because a larger machine often has a higher rating, although this varies between models.
- Temperature range: Wikipedia says most foods are dehydrated at 130°F (54°C) and jerky at a higher 155°F (68°C),[2] while Montana State University Extension gives 140°F (60°C) as the optimum for drying food.[3] A range of 40 to 70°C covers all three.
- Timer: Vegetable drying times range widely in the Montana State table,[3] so a timer helps you plan when to check the food. Check the instructions on leaving it running unattended.
- Outside size and weight: A machine used a few times a year has to be stored the rest of the time, so check its footprint, height and weight.
How Do You Work Out Trays and Watts for Your Own Produce?
- Estimate your usual surplus. Think of a basket of apples, not your biggest harvest.
- Work out the drying area. Multiply tray length by width by the number of trays, in square centimetres.
- Compare it with a reference. The National Center for Home Food Preservation uses 12 square feet per half-bushel.[1] As our own rough rule of thumb, based on tray footprint, a machine with about a third of that area suits smaller batches, and one with about two thirds suits regular gluts.
| If this describes you | Look at first | Why |
| You dry a few trays of fruit a few times a year | A 5-tray model at around 250W | Usually a lower cost per hour and a smaller machine to store |
| You have regular gluts from a garden or allotment | About 6 trays and a timer | More food per batch means fewer batches |
| You want to dry herbs, fruit and jerky | A range that reaches about 70°C | Jerky is dried hotter than most foods and needs extra heating steps for safety, set out in the National Center for Home Food Preservation’s jerky guidance, which gives 160°F (71°C)[5] |
| You have little cupboard space | The smallest machine that fits your usual batch | You have to lift and store it between uses |
How Much Does a Food Dehydrator Cost to Run?
Energy is power multiplied by time,[4] so cost is kilowatts multiplied by hours and by the price per kilowatt-hour.
- Formula: Watts divided by 1,000, multiplied by hours, gives kilowatt-hours. Multiply that by the pence per kWh on your bill.
- Example: A 245W machine running for 10 hours uses 2.45kWh and a 550W machine uses 5.5kWh. At an example rate of 25p per kWh, which is not a current price, that is about 61p and £1.38.
- Hours: Montana State’s vegetable drying times run from 1 to 18 hours.[3]
- Limits: The estimate assumes the machine draws its listed rating throughout. A larger machine uses more each hour but holds more food, so cost per kilogram depends on filling it.
How Should You Store Dried Food?
- Cooling and conditioning: The National Center for Home Food Preservation says to cool dried food completely before packing, because warm food sweats and the moisture can let mould grow. For fruit, it says to pack the cooled pieces loosely in jars, shake them daily for 7 to 10 days and return the fruit to the dehydrator if condensation forms.[6]
- Containers and place: It recommends clean, dry jars, tight-lidded freezer containers or freezer bags, kept somewhere cool, dry and dark. Most dried fruit keeps about 1 year at 60°F (16°C) and 6 months at 80°F (27°C). It says vegetables keep for about half as long, although Montana State gives 1 year at 60°F and 6 months at 80°F for vegetables, so plan on the shorter time.[6][3]
- Checking: Check the food regularly and discard any that has gone mouldy.[6] These are US guidelines.
Which Electrical Safety Marks Should You Check on a Food Dehydrator?
The Electrical Equipment (Safety) Regulations 2016 generally cover equipment designed for 50 to 1000V AC,[7] which in our view would include a mains food dehydrator. GOV.UK says CE marking is generally recognised in Great Britain alongside or in place of UKCA marking, although rules can differ for specific products,[8] so check the product or its packaging. In our view, look for automatic shut-off and overheat protection, because a machine can run for many hours.
Worked Example: A 5-Tray and a 6-Tray Food Dehydrator
Two HOMCOM food dehydrators, one with five trays at 245W and one with six at 550W, show how the numbers differ.[9][10] They are examples, not recommendations, compared on what each page states, and we did not test them.
| Check | 5 trays | 6 trays |
| Product | HOMCOM 5 Tier Food Dehydrator | HOMCOM 6 Tray Food Dehydrator |
| Power listed | 245W | 550W |
| Tray size as listed (cm) | 31W x 23D x 3.5H | 42L x 28W x 3H |
| Tray area (our arithmetic from listed size) | About 3,600 cm² | About 7,100 cm² |
| Maximum load as listed | 5kg | 6kg |
| Size as listed (cm) | 32W x 25D x 26H | 43W x 29.5D x 28H |
- Capacity and power: The 6-tray has one more tray but about twice the tray area and 2.2 times the wattage, so wattage rises roughly in line with tray area for these two, though other models differ. Against the 12 square feet reference, the two tray areas come to about a third and about two thirds, by our arithmetic.
- Not stated or inconsistent: The 5-tray page gives its lowest temperature as 35°C in one place and 40°C in others, lists automatic shut-off as No and lists no timer. The 6-tray page lists a 48 hour timer and automatic shut-off, but also a 12 hour drying time. Neither page mentions overheat protection or a CE or UKCA mark.
- Price and delivery: On 13 October 2026 the listed prices were £33.99 (5 trays) and £49.99 (6 trays), with free UK mainland delivery and returns requested within 30 calendar days of delivery.[9][10]
Five Mistakes to Avoid When Choosing a Food Dehydrator
- Choosing on tray count alone. Tray sizes differ, so compare tray area.
- Choosing on wattage alone. Wattage says little about drying, so compare it only between similar machines.
- Buying for the biggest glut. A larger machine takes more room and power for every other batch.
- Going by the clock. Montana State says to dry vegetables until they are brittle or crisp, not for a fixed time.[3]
- Skipping the storage step. Food packed warm or not dry enough can sweat and grow mould.[6]
Checklist: Six Questions Before You Buy
- How much will you usually dry at once, and how much tray area does that need?
- Does the temperature range cover about 40 to 70°C?
- Does the listing show a timer and automatic shut-off?
- What would a typical batch cost at your pence per kWh?
- Where will the machine be stored, and can you lift it?
- Do you have clean, dry jars for the dried food?
Our Recommendation
Size a dehydrator by tray area and how often you will use it, not by tray count. About 5 trays and 250W suit occasional surplus in our view, and about 6 trays at 350 to 550W suit regular gluts. Work out running costs from watts, hours and your pence per kWh, choose a range covering about 40 to 70°C, and store dried food cool, dry and dark.
FAQs
1. Can I add extra trays to a 5-tray food dehydrator?
2. Does higher wattage mean faster drying?
3. Do I need to rotate trays or slice the same thickness?
4. Can a 250W beginner dehydrator make jerky safely?
Jerky needs higher heat and extra safety steps. The National Center for Home Food Preservation gives 160°F (71°C) for jerky and separate heating guidance, which is hotter than the 130°F (54°C) for most foods. At time of writing check if the model you choose reaches about 70°C and lists automatic shut-off and overheat protection – neither of the two HOMCOM pages lists overheat protection.[5][2]
References
[1] National Center for Home Food Preservation, University of Georgia. Food Dehydrators.
https://nchfp.uga.edu/how/dry/drying-general/food-dehydrators/
[2] Wikipedia. Food dehydrator.
https://en.wikipedia.org/wiki/Food_dehydrator
[3] Montana State University Extension. Drying Vegetables, MontGuide MT200907HR (revised May 2017).
https://extension-store.montana.edu/montguides/drying-vegetables
[4] Wikipedia. Kilowatt-hour.
https://en.wikipedia.org/wiki/Kilowatt-hour
[5] National Center for Home Food Preservation, University of Georgia. Jerky. https://nchfp.uga.edu/how/dry/jerky.html
[6] National Center for Home Food Preservation, University of Georgia. Packaging and Storing Dried Foods.
https://nchfp.uga.edu/how/dry/drying-general/packaging-and-storing-dried-foods/
[7] legislation.gov.uk. The Electrical Equipment (Safety) Regulations 2016, regulation 3.
https://www.legislation.gov.uk/uksi/2016/1101/regulation/3
[8] GOV.UK. Placing UKCA or CE Marked Products on the Market in Great Britain.
https://www.gov.uk/guidance/using-the-ukca-marking
[9] HOMCOM 5 Tier Food Dehydrator, 245W Stainless Steel Food Dryer Machine with Adjustable Temperature for Drying Fruit, Black, product page.
https://www.aosom.co.uk/item/homcom-5-tier-food-dehydrator-245w-stainless-steel-food-dryer-machine-with-adjustable-temperature-for-drying-fruit~20UMRIIJ1V000.html
[10] HOMCOM 6 Tray Food Dehydrator, 550W Food Dryer Machine with Adjustable Temperature, 48H Timer, product page.
https://www.aosom.co.uk/item/homcom-6-tray-food-dehydrator-550w-freeze-dryer-machine-with-adjustable-temperature-48h-timer-for-drying-fruit-meat~1RIEODHTQ0G00.html