HUUM UKU 4.2 Mirror - Sauna Control w/ Wi-Fi, Digital On/Off, Time, Temperature
The HUUM UKU 4.2 Mirror is HUUM's newest sauna control and replaces the UKU 4.1. Set the temperature, timer and delayed start from the wall-mounted control panel, or heat the sauna from anywhere through the HUUM mobile app.
UKU 4.2 adds a second sensor. The safety sensor mounts on the ceiling above the heater and keeps the temperature near the heater under control. The new bench sensor reads temperature and humidity at bench level, where you sit, for more precise readings. Installing the bench sensor is optional. The set also includes one long heat-resistant cable that serves the control panel, both sensors and the door sensor, plus an upgraded door sensor kit.
The Mirror control display panel has a contemporary mirrored finish and can be recessed or surface-mounted. For heaters over 11kW, up to 18kW, add the UKU Extension Box.
Sauna heater sold separately.
Features & materials
- New for UKU 4.2: two sensors, a safety sensor above the heater and an optional bench sensor
- Bench sensor reads temperature and humidity at bench level, where you sit
- One long heat-resistant cable serves the control panel, sensors and door sensor
- Upgraded door sensor kit for more installation flexibility
- Stylish Mirror control display panel
- Display panel can be recessed or surface-mounted
- For electric heaters up to 11kW (over 11kW up to 18kW requires an UKU extension box)
- Compatible with other manufacturers' electric heaters
- Settable temperature range of 104-230°F
- Timer for heating start time and duration
- Heat the sauna from anywhere with the HUUM mobile app (2.4 GHz Wi-Fi network required)
- Schedule heating in the app up to two months ahead
- Also controllable from the wall-mounted control panel
- Connects to lights, ventilation and a steamer (not included)
- Overheat protection
- Child safety lock
- Door sensor keeps the heat inside the room
- Limited 3-year residential warranty and limited 1-year commercial warranty
Manuals & documents
Shipping & delivery
Shipping cost: Shipping is charged by the total weight of your order. This item on its own ships for $129 within the contiguous US, and the exact amount for your whole order is shown at checkout before you pay.
Most in-stock orders ship within 3–5 business days of confirmed payment, and delivery is typically 5–15 business days after shipment. Made-to-order saunas and custom-configured rooms need production time on top of that, which we confirm before the order is released. We ship within the contiguous United States.
Large items ship LTL freight on a pallet, delivered curbside — to the curb or the end of your driveway, often from a trailer up to 53 feet long. Curbside does not include unpacking, assembly, installation or electrical connection. The carrier calls to book an appointment and someone must be there to receive the shipment. Tell us at the time of order if access is limited — narrow or rural roads, steep driveways, gated communities — and ask for liftgate service if you have no dock or forklift.
Inspect the shipment before the driver leaves and before you sign. Count the cartons and pallets against the paperwork, check glass doors and panels, write any damage or shortage on the Delivery Receipt, and photograph it. Email info@plungeintosaunas.com within 48 hours of delivery with your order number, photos and the noted receipt — the same window covers concealed damage and missing items. Keep the packaging while a claim is open.
Cancellations & returns
Cancel before the order has been submitted for fulfillment and it is refunded in full — email info@plungeintosaunas.com with your order number. After that point manufacturer, carrier, return-freight or restocking fees may apply. Every return must be approved by us in writing first: products ship from different manufacturer warehouses, so the correct return address varies, and anything sent back without authorization may be refused.
Return requests are made within 30 days under our general policy; some brands run that window from the date of purchase rather than delivery. Items must be unused, uninstalled, never heated or filled, complete in their original packaging and in resalable condition. Restocking fees run up to 25% depending on the manufacturer, while Harvia, HUUM, SaunaLife, Saunum, Narvi, ThermaSol, Delta, Kohler and Mr. Steam charge no restocking fee at all, only a re-boxing fee of roughly $20–$50 if the original packaging does not come back intact. On a change-of-mind return you pay return shipping and the original outbound shipping is not refunded.
If the item arrived damaged or a manufacturer error is at fault, return shipping is covered for you. Custom, made-to-order and special-order items already in production, clearance and open-box items, heaters that have been wired or fired, tubs and generators that have been filled, assembled or heated rooms, opened consumables and all Canadian Timber Collection products cannot be returned. Ask us before you buy if you are unsure.
- Shipping: $129For this item on its own · contiguous US
- Authorized dealerFull manufacturer warranty
- Sized by a specialistRoom, heater and install checked
- Talk to a human(888) 739-3321
Model specifications
The figures that decide the buy. The complete sheet ships with the manual.
- Model
- UKU 4.2 Mirror
- Part number
- V2-UKU-WIFI-MIRROR
- Panel Option
- Mirror
- Minimum Temperature
- 104°F
- Maximum Temperature
- 230°F
- Maximum Heater Power
- 11kW (up to 18kW with UKU Extension Box)
- Sensors
- Safety sensor and bench sensor (temperature and humidity)
- Connectivity
- Wi-Fi (2.4 GHz) and HUUM mobile app
- Shipping Weight
- 20 lbs
Manufacturer figures. The complete specification sheet, clearances and wiring details are in the manufacturer's installation manual. See the Manuals tab above.
Everything in the box
Exactly what ships with this model, straight from the manufacturer's packing list.
- Mirror control display panel
- Main control module
- Safety sensor
- Bench sensor (installation optional)
- 2 sensor housings
- Door sensor kit
- Heat-resistant cable for the control panel, sensors and door sensor
- Installation and operation manual
- Limited 3-Year Residential Warranty and 1-Year Commercial Warranty
Sauna stones, water treatment and accessories are sold separately unless listed above.
Talk it through with a sauna specialist
Room size, heater match, electrical, delivery access — a ten-minute call answers most of it. No pressure, no sales script.
Daily, 8 AM to 7 PM Pacific. Or email info@plungeintosaunas.com any time.
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Sizing & fit
We'll check the footprint, ceiling height and heater match for your space. -
Electrical & site
What your electrician needs to know before you order. -
Delivery
Lead time, freight access and what to expect on delivery day.
What happens next
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1
We check the order
A sauna specialist reviews the configuration, the delivery address and freight access, and usually calls you to confirm it before the order is released to the manufacturer. Anything that needs changing gets changed before it ships.
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2
Confirmation and lead time
You get an email with the confirmed lead time, the manuals for your unit and what to prepare on site. Tracking follows within 24 hours of it leaving the warehouse.
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3
Delivery day and after
The freight carrier calls to book a curbside appointment — count the cartons and note any damage on the delivery receipt before you sign. Assembly, electrician and warranty questions after that come to us, and we handle them with the manufacturer on your behalf.
Frequently Asked Questions
Yes! Shop Pay Installments may be available at checkout, allowing you to split your order into installment payments, with interest-free options on eligible orders and monthly plans from 0–36% APR. Just select Shop Pay at checkout to see your options.
Warranty coverage varies by manufacturer and product. Please refer to the product page or included documentation for specific details. Warranties are provided by the manufacturer. We're happy to help connect you with the manufacturer if you have a warranty question.
We ship within the contiguous United States only. We do not currently ship to Alaska, Hawaii, PO boxes, APO/FPO addresses, or international destinations.
No. Standard curbside delivery means the carrier delivers to the curb or end of your driveway only. The driver is not required to bring items into your home, garage, or backyard, and delivery does not include unpacking, assembly, or installation.
Yes. Our store is secured with SSL encryption and all payments are processed through Shopify's secure checkout. We never store your full credit card information.
Exchanges are handled on a case-by-case basis. Contact us at info@plungeintosaunas.com with your order number and the item you'd like instead. If approved, you may be responsible for price differences, return shipping, and any applicable restocking fees.




