Frequently asked
questions.

The All Season Pro (model EMF502) is a water-circulating sleep temperature system that sits over your existing mattress. A compact SleepHub circulates temperature-controlled water through the pad to cool or warm your sleep surface in precise 1°F increments — year-round. It works with whatever bed you already have, individualizing your sleep temperature experience for both you and your partner.

The All Season Pro covers 64°F to 113°F (18°C to 45°C) across two modes: COOL+ mode for cooling (64–95°F) and WARM mode for heating (82–113°F). Temperature is set in 1°F increments — a precise degree, not a level or range. Switch freely between modes by season or preference. Actual pad temperature can vary slightly depending on your room’s environment, so allow a short window for it to settle. For consistent performance, make sure the SleepHub’s air inlet isn’t blocked or covered.

This is expected, not a defect. The All Season Pro uses a Peltier element to cool water, which can bring the pad up to about 9°F (5°C) below room temperature. For example, in an 86°F (30°C) room, COOL+ mode typically reaches 77–95°F (25–35°C). We don’t recommend setting the pad far below room temperature, for comfort and safety.

The Queen and King sizes include two independent water circuits — one for each side of the bed. Each sleeper sets their own temperature via the Navien Sphere for Sleep app or the SleepHub’s front panel display, completely independently — you might set 68°F while they prefer 78°F.

The All Season Pro works with most standard mattresses — innerspring, hybrid, and the majority of foam mattresses. Note: We do not recommend use with latex mattresses, as direct contact between the water pad and latex material may cause deformation. We also do not recommend use with adjustable bed frames that flex or articulate at the head or foot — bending the pad may obstruct internal water flow channels and prevent normal operation. Contact us if you have questions about your specific setup.

The pad is ultra-thin and lies flat under your fitted sheet, so it shouldn’t change how your mattress feels to sleep on. That said, feel can vary by mattress type — very soft pillow-tops, plush comfort layers, or memory foam may make the pad slightly more noticeable. Most sleepers report little to no difference at all.

In WARM mode, the unit operates quietly — only the water circulation pump runs. In COOL+ mode, a fan also runs for the cooling system, producing additional airflow sound — similar to a small desk fan. On first startup, a brief high-speed pump cycle runs for about 3 minutes as air is cleared from the system, then settles to normal. This is expected behavior, not a malfunction.

Two covers are included — one for cooling, one for warming. The COOL cover uses a specialized cooling fabric for a faster, more effective cooling sensation. The WARM cover is made from an anti-allergen fabric designed to help block dust and dust mites. Both feature a waterproof-coated protector layer for safer, cleaner use.

COOL cover: Polyester 77% / Polyethylene 23%  ·  WARM cover: Polyester 100%  ·  Protector: Polyester 100% + PU coating (waterproof)

The cover is designed to fit mattresses ranging from 10 to 20 inches in height — covering the full range of commonly sold US mattress profiles. The design ensures a clean, fitted appearance across both standard (10–13 inch) and thicker mattress heights.

Yes. The cover is not a strict square profile — it is designed to be compatible with both squared and rounded mattress edge styles, accommodating the variety of mattress profiles sold in the US market.

Water-circulating products carry theoretical leak risk, and we take it seriously. The All Season Pro uses a sealed, low-pressure water circuit with a closed-loop design and easy-click connector fittings. Leak detection is built into the system (error code Er 28) — the unit alerts you and shuts off automatically if a leak is detected. This is an area where Navien’s 48 years of temperature engineering heritage genuinely matters.

Pad and cover dimensions by size:

Size	Pad	Cover (mattress size)
Full	49″ × 74″	54″ × 75″
Queen	57″ × 77″	60″ × 80″
King	65″ × 77″	76″ × 80″

Dimensions may vary by ±1.5″ due to manufacturing tolerances.

Note: On the King size, the water-circulating pad measures 65″ × 77″ — smaller than the full King mattress surface (76″ × 80″). It’s sized to cover the primary sleeping area rather than every inch of the mattress, so temperature control stays focused where you actually sleep.

SleepHub: 12.2″D × 7.8″W × 13.1″H, 17.6 lbs. Power cable length: 56″.