{"product_id":"huum-uku-ext-box","title":"HUUM UKU Extension Box (Contactor, 12 kW+)","description":"\u003cp\u003eThis is the HUUM UKU extension box — the contactor you add when the heater is over 12 kW. On this shop that means HIVE 12 \/ 15 \/ 18. It is not a control panel and it is not a heater. UKU WiFi (any finish) is sold separately; this box rides with that system.\u003c\/p\u003e\u003ch3\u003eWhat’s included\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eHUUM UKU extension box \/ contactor enclosure\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eUKU control sold separately\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eHeater sold separately\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eSpecs\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e HUUM (Estonia)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eModel:\u003c\/strong\u003e UKU extension box\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSKU:\u003c\/strong\u003e 536-UKU-EXT-BOX\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Contactor \/ extension module for UKU\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRequired with:\u003c\/strong\u003e UKU on HUUM heaters over 12 kW — HIVE 12 \/ 15 \/ 18 on this shop\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNot required with:\u003c\/strong\u003e DROP, HIVE Mini (6 \/ 9 \/ 11), CLIFF, STEEL, CORE (all ≤ 11 kW in our list)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUKU with this box (HUUM US):\u003c\/strong\u003e up to 18 kW\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eControl panel in the carton:\u003c\/strong\u003e No\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeater in the carton:\u003c\/strong\u003e No\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eDownloads\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/huumsauna.com\/wp-content\/uploads\/2025\/11\/H3283_v5_extension-box_wiring-instructions_US_297x210mmbleed_V-fold_PRINT.pdf\" target=\"_blank\" rel=\"noopener\"\u003eHUUM UKU extension box US wiring instructions (PDF)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/huumsauna.com\/wp-content\/uploads\/2026\/01\/H200402L03_v9_UKU_4_1_User_Manual_US_PRINT.pdf\" target=\"_blank\" rel=\"noopener\"\u003eHUUM UKU 4.1 US user manual (PDF)\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eDoes this replace UKU?\u003c\/strong\u003e\u003cbr\u003eNo. You still need a UKU WiFi (or Local) package. This is the extra box for 12 kW+.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHIVE 12STUX package?\u003c\/strong\u003e\u003cbr\u003eSTUX already names UKU. Confirm with our team whether today’s carton also has the extension box before you add this SKU.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWood stove?\u003c\/strong\u003e\u003cbr\u003eNo. HIVE Wood does not use UKU.\u003c\/p\u003e\u003cp\u003eEmail hello@selfcaresaunas.com if you want him to pair UKU with a HUUM heater size. A licensed electrician completes the hookup from the HUUM table — we do not invent amps.\u003c\/p\u003e\u003cp\u003eQuestions? Email hello@selfcaresaunas.com or email hello@selfcaresaunas.com.\u003c\/p\u003e","brand":"HUUM","offers":[{"title":"Default Title","offer_id":44074518872123,"sku":"536-UKU-EXT-BOX","price":773.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0618\/3279\/0075\/files\/Extension-box-EU-web.png?v=1788059337","url":"https:\/\/selfcaresaunas.com\/products\/huum-uku-ext-box","provider":"Self Care Saunas","version":"1.0","type":"link"}