Heated mattress pads / Roundup
King size heated mattress pads
The biggest heated surface you can put in a bed, and the size where dual control stops being optional. Four pads, one published wattage, and a 5-year warranty worth noticing.
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The Bedsure king pad is the pick because it is the only one of the four that publishes a wattage: dual 100 W controllers, so about 29 cents for an eight-hour night with both zones on. The Sealy is the alternative if a stated 5-year warranty and a published 20-minute preheat matter more than the number.
The picks, with the numbers
Ranked on what the maker publishes, not on a score we invented. Tap a row for the full write-up, or go straight to the listing. Cost is 8 hours at the rated wattage and $0.1834/kWh.
| # | Product | Best for | Watts | Per night | Price |
|---|---|---|---|---|---|
| 1 |  Top pickBedsure Heated Mattress Pad, KingDual 100 W controllers stated on the listing. As with the queen, it is the only king-size pad we found that publishes any power figure at all. | The only king pad with a published wattage | 200 W | 29 cents | $99.99 - See it on Amazon |
| 2 |  Sealy Heated Mattress Pad, King, Dual ControlPublishes two things almost nobody else does at this size: a stated preheat duration and a five-year warranty. Still no wattage. | A 20-minute preheat and a 5-year warranty | Not published | Uncomputable | $104.98 - See it on Amazon |
| 3 |  Serta Heated Mattress Pad, KingThe king version of Serta's protector-plus-warmer pad, with dual-zone control and an hour-by-hour shut-off. | Doubling as a mattress protector | Not published | Uncomputable | $121.25 - See it on Amazon |
| 4 |  Valthie Heated Mattress Pad, KingThe finest heat granularity of any king pad here, with dual controllers and a full 12-hour timer range. No wattage. | Twelve settings at king size | Not published | Uncomputable | $89.99 - See it on Amazon |
Sources: wattage from each maker's own published listing, cited on the card below. Cost is our arithmetic at the EIA rate, shown in full on cost to run.
#ad how we are funded - price as of September 19, 2026
The only king pad with a published wattage
Bedsure Heated Mattress Pad, King
Rated wattage
200 W
8 hours costs
29 cents
#ad how we are funded - price as of September 19, 2026
Dual 100 W controllers stated on the listing. As with the queen, it is the only king-size pad we found that publishes any power figure at all.
Where the wattage comes fromBedsure states 120V AC at 60Hz with dual 100W controllers, the same rating as its queen pad. Both zones at full is 200W; one zone alone is 100W, which is how most couples use it.
200 W x 8 h = 1.60 kWh, x $0.1834/kWh = $0.29 per night
- Size
- King, fits up to 18" deep
- Heat settings
- 10 levels
- Auto shut-off
- 12 time settings
- Controllers
- 2 (dual control)
- Certification
- ETL and FCC certified
- Warranty
- Not stated on the listing
- Rated watts
- 200 W (dual 100 W)
- Voltage
- 120 V AC, 60 Hz
- Pocket depth
- Stretches to 18"
- Preheat
- Yes, with memory
- Model
- BS-HMKI-2
What it does well
- The only king pad in our set that publishes a wattage
- Dual control as standard at this size
- All-round elastic to 18" so it does not creep on a deep mattress
- ETL and FCC certified, with 74 in-house safety tests stated by the brand
Where it falls short
- No warranty term stated
- No waterproof layer on this version
- 200 W with both zones at full is the highest published draw on the site
Who this is forA king bed with two people in it who want the running cost on the table before buying.
Skip it ifSkip it if you need waterproofing. Bedsure's cotton-top pad has a TPU layer and this one does not.
A 20-minute preheat and a 5-year warranty
Sealy Heated Mattress Pad, King, Dual Control
Rated wattage
Not published
8 hours costs
Uncomputable
#ad how we are funded - price as of September 19, 2026
Publishes two things almost nobody else does at this size: a stated preheat duration and a five-year warranty. Still no wattage.
Where the wattage comes fromNo wattage published, in line with every Sealy heated-bedding listing we have checked across blankets, throws and pads. Sealy publishes cord lengths, warranty terms and temperature ranges, but never a power figure.
- Size
- King
- Heat settings
- 10 levels
- Auto shut-off
- Stated on the controller
- Controllers
- 2 (dual control)
- Certification
- Not stated on this listing
- Warranty
- 5 year warranty
- Rated watts
- Not published
- Preheat
- 20 minutes, stated
- Surface
- Quilted, 3M Scotchgard water-repellent treatment
- Model
- KTHM-QATMF-K
What it does well
- 5-year warranty, the longest stated term of any king pad here
- A published 20-minute preheat, which is a real number rather than a vague claim
- 3M Scotchgard water-repellent treatment named specifically
- Machine washable with the power cord unplugged from the controller
Where it falls short
- No published wattage
- Water repellent is not the same as a waterproof barrier
- No certification named on this particular listing
Who this is forA king bed where a long warranty and a fast, stated preheat matter more than a running-cost figure.
Skip it ifSkip it if you need a true waterproof barrier. Repellent treatment sheds a splash; it is not a membrane.
Doubling as a mattress protector
Serta Heated Mattress Pad, King
Rated wattage
Not published
8 hours costs
Uncomputable
#ad how we are funded - price as of September 19, 2026
The king version of Serta's protector-plus-warmer pad, with dual-zone control and an hour-by-hour shut-off.
Where the wattage comes fromNo wattage published on the listing or in the technical details table.
- Size
- King, deep pocket
- Heat settings
- 10 levels
- Auto shut-off
- 1-12 hours, in 1-hour increments
- Controllers
- 2 (dual zone on queen and larger)
- Certification
- ETL certified
- Warranty
- Not stated on the listing
- Rated watts
- Not published
- Construction
- Microfiber top over bonded polyfill
- Doubles as
- Mattress protector against spills and pet accidents
- Model
- ST55-0276
What it does well
- Sold as a protector as well as a warmer, so it earns its place in summer
- Dual zone standard at king size
- Timer settable in single-hour steps up to 12
- ETL certified and independently tested
Where it falls short
- No published wattage
- Bonded polyfill adds loft you may not want on a soft mattress
- No warranty term stated
Who this is forA king bed that needs protecting from spills as much as it needs warming.
Skip it ifSkip it if your mattress is already soft. The polyfill layer is a real addition you will feel.
Twelve settings at king size
Valthie Heated Mattress Pad, King
Rated wattage
Not published
8 hours costs
Uncomputable
#ad how we are funded - price as of September 19, 2026
The finest heat granularity of any king pad here, with dual controllers and a full 12-hour timer range. No wattage.
Where the wattage comes fromNo wattage published on the listing or in the technical details.
- Size
- King
- Heat settings
- 12 levels
- Auto shut-off
- 1-12 hours
- Controllers
- 2 on king; 1 on twin, twin XL and full
- Certification
- Overheating protection stated; no certification named
- Warranty
- Not stated on the listing
- Rated watts
- Not published
- Fabric
- 100% polyester, breathable
- Controller
- Upgraded, with long cord run
What it does well
- 12 heat settings, the finest of any king pad in our set
- Dual controllers at king size
- Overheating protection and a full 12-hour timer range
- Washable with the power cable detached
Where it falls short
- No published wattage
- No named safety certification in the listing copy
- No warranty term stated
Who this is forSomeone who wants fine control on a king pad and is comparing on features.
Skip it ifSkip it if a named certification matters to you. Overheat protection is claimed; a UL or ETL listing is not stated.
How we ranked these
- Published wattage first. On the largest heated surface in the house, the running cost is the number most worth having, and exactly one of these four supplies it.
- Dual zone second. At king size a shared bed is the default, and every pad here ships two controllers.
- Then pocket depth, auto-off ceiling and waterproofing, which decide whether it fits, switches off when you want, and survives the household.
- Not ranked on comfort or loft. We have not slept on any of these.
We have not handled these products and we do not claim to have. The full method, including the rubric weights and what we refuse to claim, is on our methodology page.
One in four publishes the number
The same pattern as every other category on this site, and at king size it matters slightly more, because this is the largest heated area you can install and it runs all night.
| Pad | Rated watts | Settings | Auto-off | Warranty |
|---|---|---|---|---|
| Bedsure | 200 W (dual 100 W) | 10 | 12 time settings | Not stated |
| Sealy | Not published | 10 | On the controller | 5 years |
| Serta | Not published | 10 | 1-12 h, 1-hour steps | Not stated |
| Valthie | Not published | 12 | 1-12 h | Not stated |
Read off each product's own Amazon listing on 2026-09-07. Every one of the four ships dual controllers at king size.
| Run time | kWh | Cost | Working |
|---|---|---|---|
| 1 hour | 0.20 | 4 cents | 200 x 1 / 1000 x 0.1834 |
| 4 hours (an evening) | 0.80 | 15 cents | 200 x 4 / 1000 x 0.1834 |
| 8 hours (a night) | 1.60 | 29 cents | 200 x 8 / 1000 x 0.1834 |
| 30 nights at 8 hours | 48.00 | $8.80 | 200 x 240 / 1000 x 0.1834 |
| A 120-night winter at 8 hours | 192.00 | $35.21 | 200 x 960 / 1000 x 0.1834 |
Rate: US Energy Information Administration, Electric Power Monthly, Table 5.3 (June 2026): 18.34 cents per kWh, average US residential. Retrieved 2026-08-31.
Rated wattage is the ceiling, not the average. A thermostatic blanket cycles its element on and off once the bed is warm, so an all-night bill usually lands below the rated-watt figure. We publish the rated number because it is the only one the maker stands behind, and we do not estimate a duty cycle for a blanket we have not measured.
The figure worth carrying away is the per-zone one. Both zones at full is 200 W and about 29 cents a night, but most couples run one side warm and the other off or low. At 100 W for one zone that is about 15 cents, which is the same as a single-control queen blanket covering far less bed.
Note also that Bedsure's king pad carries the same 200 W rating as its queen pad. The king is a bigger pad with the same controller rating, which is a reminder that wattage tracks the element and controller configuration rather than surface area.
What Sealy gives instead of a number
Sealy's king pad is the most interesting product here after the Bedsure, because it publishes two things almost nobody else does at any size.
- A 5-year warranty, stated. On a product that will run several hundred nights a season, a manufacturer committing to five years is a real signal, and it is the longest term of any king pad we found.
- A 20-minute preheat, given as a duration. Most brands claim a preheat function without saying how long it runs or what it does. Twenty minutes is a number you can plan around.
- 3M Scotchgard water-repellent treatment, named specifically rather than described as water resistant.
None of that lets you compute a running cost, and we are not going to pretend it does. But if you were choosing on what a maker will commit to in writing rather than on the electricity bill, Sealy would win this page.
Repellent is not waterproof
Worth separating, because the words get used interchangeably and the difference matters on a bed with a child or an animal in it.
Sealy's Scotchgard treatment is a surface repellent: it will shed a splash. Serta positions its pad as a mattress protector, which is a coverage claim about keeping spills off the mattress. Neither is a barrier membrane of the kind Bedsure puts in its cotton-top queen pad. If the scenario you are buying for is a full accident rather than a spilled glass, none of these four is the answer and the barrier version is on waterproof heated mattress pads.
Why dual zone matters more at this size
A king pad heats the surface both of you are lying on, and heat conducts sideways through the mattress core rather than stopping neatly at the middle. The boundary between zones is softer than the marketing diagram suggests.
Two practical consequences. Dual control is genuinely necessary here rather than a luxury, and all four of these ship it. And the sensible pattern is smaller differences between the two settings than you would use on a blanket, because a very warm zone on one side is noticeable on the other. More on the mechanism in dual control heated mattress pads.
Two controllers, two cables, one head of one bed
The practical problem nobody mentions until you are installing it. Two controllers both sit at the head of a king bed and both need to reach power, which usually means a socket on each side or one run long enough to cross behind the headboard. Measure before you order.
And the instruction that appears in capitals on several of these listings: do not leave the controller covered while in use. It is the part that senses temperature, and a controller under a duvet reads the duvet.
Questions people actually ask
- What is the best king size heated mattress pad?
- The Bedsure king pad on the evidence available: it is the only one of the four we track that publishes a wattage (dual 100 W controllers), it is dual control, and it stretches to an 18-inch pocket. The Sealy is the alternative if a stated 5-year warranty matters more.
- How much does a king heated mattress pad cost to run?
- For the only one publishing a figure, Bedsure's dual 100 W: about 29 cents for an eight-hour night with both zones on and about 15 cents with one, at $0.1834/kWh. Sealy, Serta and Valthie publish no wattage.
- Do king heated mattress pads have dual controls?
- All four in this roundup do. Dual control is standard from queen size up across every brand we track, and at king size no manufacturer we found offers a single-control option.
- Will a king heated mattress pad fit a deep mattress?
- All four claim to fit up to about 18 inches. Measure your mattress including any topper before ordering, because a pad that is fractionally too small creeps in the night and bunches the element.
Sources
Every specification on this page traces to a published manufacturer listing or a government data source. Where a maker publishes no wattage, we say so rather than estimating one.
Read next
- The best heated mattress padsSix pads compared, and the single brand that tells you what its pad draws.
- Dual control heated mattress padsTwo zones under one sheet, and the size threshold where dual control starts.
- Waterproof heated mattress padsWaterproof, water resistant and protector are three claims. Only one is a barrier.
- Sealy heated blanketsTemperature ranges and five-year warranties, and never once a wattage.
- King size electric blanketsTwo kings at 90 by 100 inches. Only one publishes what it draws.