Double barrel heaters come in several forms, from spa replacement elements to outdoor patio and wood-burning barrel kits. This guide reviews five double barrel heater products and accessory kits commonly used for hot tubs, patios, and DIY barrel stoves to help you compare features and compatibility.
| Product | Type | Primary Feature |
|---|---|---|
| Therm 26-C3160-2S 4KW Watkins | Spa/Hot Tub Heater | Watkins Low Flow Double Barrel Design |
| Therm C3564-1 6kW 240V | Spa/Hot Tub Heater | Low-Flo 240V Replacement With Manual Reset |
| Hydro-Quip 48-0041B-K Barb Kit | Accessory Kit | 3/4″ Barb Kit For Watkins Double Barrel |
| Hydro Quip 48-0041A-K Gasket Kit | Accessory Kit | Gasket Set For Watkins Double Barrel |
| Double Barrel Stove Kit (SONRET) | Wood-Burning Barrel Stove Kit | Double-Barrel Design For 30–55 Gal Drum |
Therm 26-C3160-2S 4KW Watkins Double Barrel Heater
This unit is listed as the Watkins Low Flow Double Barrel Heater, designed for spa and hot tub applications that require a low-flow heater element. The double barrel design improves heat transfer surface area compared to single-tube elements and is commonly used as a replacement assembly for compatible Watkins/Hot Springs equipment.
- Compatibility: Intended as a replacement for specific Watkins models; verify model fit before purchase.
- Power Rating: 4 kW—suitable for smaller hot tubs or systems designed for low-flow heating elements.
- Use Case: Replacement element for service or repair when original double-barrel heaters fail.
Therm 6kW C3564-1 Double Barrel Heater
The 6kW Therm Products C3564-1 is listed as a 240V low-flow replacement element with a manual reset feature. It’s marketed as compatible with Hot Springs and similar systems that require 240V heating elements. The larger kilowatt rating provides faster heating in appropriately sized equipment.
- Power and Voltage: 6 kW, 240V only—ensure electrical compatibility.
- Manual Reset: Built-in manual reset provides a safety mechanism for thermal events.
- Replacement Role: Replaces specific part numbers; confirm compatibility before ordering.
Hydro-Quip 48-0041B-K Barb Kit For Double Barrel
The Hydro-Quip Barb Kit (3/4″) is an accessory intended for use with Watkins double barrel heaters. Barb fittings allow flexible tubing connections to the heater assembly, useful when replacing or servicing the plumbing on a spa heater.
- Fitment: 3/4″ barb size—confirm tubing inner diameter and compatibility.
- Application: Replacement plumbing hardware when updating hose connections or repairing leaks.
- Installation Note: Proper clamps and heat-resistant tubing are recommended for spa applications.
Hydro Quip 48-0041A-K Gasket Kit For Double Barrel
The Hydro Quip Gasket Kit is a service part for Watkins double barrel heaters. Gaskets are critical to maintain a watertight seal where the heater assembly interfaces with plumbing or housing components and are commonly replaced when heater units are serviced.
- Package Dimensions: Listed package length 5.9 inches—verify all gasket shapes and counts in product photos or manufacturer documentation.
- Maintenance Role: Replace when leaks, deterioration, or maintenance requires heater disassembly.
- Compatibility Tip: Match gasket set to the exact heater model for correct sealing surfaces.
Double Barrel Stove Kit For 30–55 Gal Drum
This Double Barrel Stove Kit is a heavy-duty steel kit designed to convert 30–55 gallon drums into a double-barrel wood-burning stove. The double-barrel approach stacks or pairs drums to increase combustion chamber volume and heat output for workshop, cabin, or outdoor heating.
- DIY Application: Intended for experienced DIY builders comfortable with metalworking and safe stove assembly practices.
- Kit Contents: Typically includes stove door, grate, connectors, and mounting pieces to form a double-barrel combustion chamber.
- Use Cases: Workshop, cabin, garage heating, or emergency heating where solid fuel is used.
Buying Guide: How To Choose The Right Double Barrel Heater
Choosing the right double barrel heater depends on the application—spa/heater replacement, accessory components, patio heating, or DIY barrel stoves. Assess the following key considerations before purchasing.
Application And Intended Use
Define the Use Case: Spa and hot tub heaters require specific electrical ratings, plumbing fittings, and safety features. Wood-burning barrel kits are structural and combustion-focused. Patio or propane heaters use different fuel and safety standards. Match the product category to your intended use.
Compatibility And Fitment
Verify Model Numbers: Replacement elements and gasket/barb kits must match the original heater part numbers or OEM compatibility lists. Check physical dimensions and electrical connectors.
Electrical Requirements: Confirm voltage (120V vs 240V), phase, and kilowatt ratings for spa heaters. Incorrect voltage will prevent operation or create hazards.
Power And Heat Output
Kilowatt/Btu Ratings: For electric spa heaters, higher kW means faster heating but requires compatible electrical circuits. For wood or barrel stoves, design and barrel volume influence heat output. Patio heaters are rated in BTUs—choose one sized for the coverage area.
Material Quality And Durability
Construction Materials: Stainless steel or high-grade metals resist corrosion in outdoor and wet environments. Gasket and barb materials should be heat and chemical resistant in spa systems.
Safety Features And Certifications
Safety Mechanisms: Spa heaters may include manual or automatic resets, high-limit switches, and thermal cutouts. Patio heaters include tip-over and flame-out protections. Wood stove kits require proper flue connections and clearance planning.
Certifications: Look for ETL, UL, CSA, or equivalent certifications for electrical and gas-fired products to ensure compliance with safety standards.
Installation And Maintenance
Professional vs DIY Installation: Electrical spa heater replacements often require licensed electricians. Plumbing parts like barb kits may be handled by a competent DIYer. Barrel stove assembly requires metalworking skills and adherence to local codes for solid-fuel appliances.
Service Parts Availability: Choose products with replacement kits (gaskets, fittings) available to simplify future maintenance.
Comparison Perspectives
- Replacement Element vs. Accessory Kits: Replacement heaters (Therm models) provide the core heating function; accessory kits (Hydro-Quip) address plumbing and sealing needs. Both are essential when servicing a spa heater.
- Electric vs Solid-Fuel Solutions: Electric double barrel heaters (Therm) are used in controlled, indoor/wet environments like spas. Solid-fuel double barrel stove kits convert drums into combustion heaters for outdoor/workshop use and require ventilation and safe clearances.
- Power Density: Compare kW (electric) and BTU (propane or fuel) outputs relative to the space to be heated. Higher nominal output requires supporting electrical infrastructure or fuel delivery.
Practical Tips Before You Buy
- Measure the existing heater assembly and confirm part numbers before ordering a replacement element or gasket kit.
- When replacing spa heater elements, turn off power and drain systems per manufacturer instructions and consider professional installation.
- For wood barrel stoves, research local codes and clearances; use certified stovepipe and spark arrestors where required.
- Check seller listings and product images for the exact parts included in kits to avoid missing components.
Warranty, Support, And Documentation
Documentation: Product manuals, wiring diagrams, and parts lists make installation and future service easier. Prefer items with clear OEM cross-reference lists.
Warranty And Support: Evaluate manufacturer warranty terms and availability of customer support for troubleshooting and part replacements.
Final Compatibility Checklist
- Confirm electrical voltage and kW rating for electric heaters.
- Match gasket shapes and barb sizes to the original plumbing connections.
- Verify drum diameter and kit fit for double barrel stove conversions.
- Ensure safety certifications match the intended installation environment.