If you’re planning to heat a space by running radiant heat between joists, these products offer reliable ways to install underfloor heating under floating or tiled floors. This guide highlights five options that suit common joist-and-subfloor installations, balancing ease of setup with effective warmth. Ideal buyers include DIY homeowners, apartment renovators, and contractors seeking energy-efficient comfort. The following summary table compares key details and suitability at a glance.
| Product | Best For | Notes |
|---|---|---|
| QuietWarmth Float QWARM1.5X5F120 | Floating floors under laminate or luxury vinyl | Cuttable length, energy efficient |
| QuietWarmth Float QWARM1.5X10F120 | Larger floating flooring areas | Same system, bigger mat |
| 15 Sq Ft 120V Electric Floor Heating System Kit | Tile or stone with programmable thermostat | Built-in sensor and monitor |
| HEATIT 20 sq.ft. Electric Underfloor Heating Cable | Custom layouts between joists | Flexible wire for edges and corners |
| 15 Sqft Electric Radiant Floor Heating Cable Kit | Tile floors in bathrooms or kitchens | WiFi/Bluetooth thermostat options available |
QuietWarmth Float QWARM1.5X5F120 Radiant Floor Heating Mat
Best for: Small to medium floating floor areas beneath laminate, wood, or luxury vinyl boards. This cuttable mat provides an easy path to radiant heat without mortars or self-leveling compounds. The 1.5′ x 5′ size covers approximately 7.5 square feet when laid straight, with the ability to tailor length to fit a room. It consumes up to 50% less power than many traditional wired systems, supporting economical operation.
Why chosen: It complements floating floor installations where joists run above a subfloor, allowing heat to rise efficiently through a floating layer. The mat is designed for quick installation and minimal mess, making it a strong choice for mid-size rooms. Limitations include that the width cannot be narrowed by cutting, which may affect layout precision in unusually shaped spaces.
QuietWarmth Float QWARM1.5X10F120 Radiant Floor Heating Mat
Best for: Larger floating floor areas requiring even heat distribution under 4mm+ floating floors. This mat offers a broader surface to reduce heat gaps and maintain comfort across bigger rooms. Like the smaller mat, it’s easy to install and energy-efficient, reducing daily operating costs compared to older heating methods.
Why chosen: It scales up the same system to cover more space, ideal when joists define a larger corridor or living area. Cautions include planning for mat width constraints and ensuring proper routing of power connections to the thermostat location.
15 Sq Ft 120V Electric Floor Heating System Kit
Best for: Tiled bathrooms or kitchens where a complete mat-and-thermostat solution is preferred. The kit includes a 15 sq ft heating mat, a 120V touchscreen thermostat, a floor sensor, and an installation monitor. It’s designed for fast, precise control of radiant heat under tile floors between joists.
Why chosen: The built-in monitor and programmable thermostat support accurate temperature management, helping reduce energy use while maintaining comfort. A limitation is that the kit is tile-focused and requires proper substrate preparation to ensure flatness and adhesion.
HEATIT 20 Sq Ft Electric Underfloor Heating Cable
Best for: Custom layouts that run between joists, especially when you need flexibility around obstacles or irregular room shapes. The loose-lay heating cable can be embedded in self-leveling underlayment or mortar to preserve floor height and provide a uniform warmth.
Why chosen: This system supports bespoke installations where standard mats won’t fit. Its small 1/8″ cable thickness minimizes raised sections. A potential drawback is the need for precise embedding in an appropriate substrate to ensure even heat distribution.
15 Sqft Electric Radiant Floor Heating Cable Kit
Best for: Tile or stone floors in bathrooms where a flexible thermostat solution is desired. This kit includes 60 feet of heating cable, a UWG5-4999 programmable thermostat, a floor sensor, and an installation monitor. The system is UL-listed for wet areas.
Why chosen: The included smart thermostat options provide convenient control, potentially lowering energy use with schedules and remote operation. Avoid this if the room layout requires rigid mats that cannot bend or if you prefer plug-and-play mats over cable-based layouts.
Buying Guide: Key Considerations For Heating Between Joists
- Floor type compatibility: Floating floors (laminate, luxury vinyl, engineered wood) typically pair with radiant mats; tile or stone often works with heating cables embedded in self-leveling underlayment.
- Installation method: Mats simplify layout but are limited by width; cables offer flexible routing between joists for irregular spaces.
- Thermostat control: Look for programmable thermostats with floor sensing, GFCI protection, and easy interfaces to regulate comfort and energy use.
- Floor height impact: Ensure the thickness of the heating element plus subflooring does not overly raise finished floor height in tight spaces.
- Power requirements and wiring: Check electrical load, circuit capacity, and compliance with local codes. Choose 120V or 240V configurations as appropriate for your space.
- Safety features: Water-resistance ratings for wet areas, circuit protection, and installation monitors help prevent damage and ensure safety.
- Maintenance and repair: Consider ease of replacement and whether the system supports alarms for damaged wiring during installation.
FAQ
- What is the main difference between mats and cables for underfloor heating?
Mats are easier to install and ideal for standard room shapes, while cables offer more design flexibility for irregular layouts or spaces between joists.
- Can underfloor heating between joists be installed over existing subfloors?
Yes, most systems are designed for installation under floating floors or over tile with appropriate substrates, but verify compatibility with your specific subfloor.
- Do these systems require professional installation?
Many DIY-friendly mats and kits are designed for homeowner installation, but electrical work and heat-minding installations may require licensed help depending on local codes.
- Will underfloor heating significantly raise utility bills?
Efficiency features and programmable thermostats help minimize costs. Systems typically use less energy than traditional heating in targeted spaces when set correctly.
- What floor types are best for radiant heat installed between joists?
Floating floors like laminate, luxury vinyl, and floating engineered wood are common, while tile or stone floors benefit from cable-based systems under a screed or self-leveling layer.
- Is there a maintenance risk with these systems?
Most systems are designed for long-term operation with in-line monitoring. Follow manufacturer guidelines on installation and use to minimize risk of damage.