---
title: HUUM UKU Ext Box UKU Extension Box for Heaters over 12kW
public-url: https://norsesteam.com/product/huum-uku-ext-box-uku-extension-box-for-heaters-over-12kw/
markdown-url: https://norsesteam.com/product/huum-uku-ext-box-uku-extension-box-for-heaters-over-12kw.md
generated: 2026-11-09
type: product
product-type: simple
brand: HUUM
sku: H2003012
price: 773.00
currency: USD
availability: in_stock
shipping-lower-48-usd: 0.00
---

# HUUM UKU Ext Box UKU Extension Box for Heaters over 12kW

HUUM | SKU H2003012 | $773.00 USD | In stock

Human page: https://norsesteam.com/product/huum-uku-ext-box-uku-extension-box-for-heaters-over-12kw/
Prices in USD, accurate as of 2026-11-09. The human page always has the live price and the order button.

## At a glance

| Field | Value |
| --- | --- |
| Brand | HUUM |
| SKU | H2003012 |
| Price | $773.00 USD |
| Availability | In stock |
| Shipping to United States 48 states | $0.00 (no shipping charge at checkout) |
| Categories | HUUM, Sauna Heater Controls, Sauna Heaters |

## Summary

**✓ Free Shipping**
**✓ No Sales Tax (except WY)**
**✓ Lowest Price Guaranteed**

## Description

### HUUM UKU Extension Box: for UKU controls paired with larger electric heaters

The HUUM UKU Extension Box is the box a UKU control needs to run a larger HUUM electric heater. It is required for heaters above 11 kilowatts and up to 18 kilowatts. It works with every HUUM UKU control, so your choice of control does not change which extension box you need.

The light gray box mounts on the wall. It was designed and made in Estonia, and the package contains the extension box. Want all your control settings on a wall panel? See the [HUUM UKU Local control](https://norsesteam.com/product/huum-uku-local-digital-on-off-time-temperature-control/). The HUUM UKU Extension Box ships free from Norse Steam with No Sales Tax (except WY) and our 100% price match guarantee.

## Features

- For use with UKU controls
- Required for all HUUM heaters over 12kW
- Light Grey
- Wall-mounted design
- Designed, engineered, and made in Estonia
- Dimensions: 7″ W (178mm) x 4″ D (101mm) x 10″ D (254mm)
- SGS Listed
- Limited 5-year warranty (excluding elements)

## Includes

- Extension box
- Installation and operation manual
- 5-Year limited warranty

## Specifications

| Model | UKU Ext Box |
| --- | --- |
| Voltage | 240 |
| Circuit Breaker Amperage | 2 x 63 |
| Weight | 3.25 lbs |
| Width | 7″ (178mm) |
| Depth | 4″ (101mm) |
| Height | 10″ (254mm) |

## Manual

[UKU Ext Box Manual 2022](https://norsesteam.com/wp-content/uploads/2023/11/UKU-Ext-Box-Manual-2022.pdf)

## Images

- https://norsesteam.com/wp-content/uploads/2023/11/huum-extensionbox.png.jpg (HUUM UKU Ext Box UKU Extension Box for Heaters over 12kW)
- https://norsesteam.com/wp-content/uploads/2023/11/huum-extension-box-open.png.jpg (HUUM UKU Ext Box UKU Extension Box for Heaters over 12kW)

## Store information

- [Shipping and order policy](https://norsesteam.com/shipping-delivery.md)
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