Quick Answer
Radiant floor heating warms a room by circulating hot water through PEX tubing (hydronic) or by running electric resistance cables (electric mat) directly under the floor finish. Heat radiates upward into the room, so you feel warm at floor level instead of from a ceiling vent. Hydronic is more efficient and cost-effective whole-house. Electric is the practical choice for single rooms like bathrooms or kitchens.
Surface temperatures top out around 82F (28C) at the subfloor. Above that, most flooring (engineered hardwood, LVP, even tile) starts to fail.
Hydronic vs Electric
- Hydronic: PEX loops, boiler or heat pump, manifold. $8 to $15 per sq ft installed. Pays back in 5 to 10 years on heating bills. Best for new builds and additions.
- Electric mat: pre-wired heating mat (Schluter DITRA-HEAT, Warmup, NuHeat). $5 to $12 per sq ft installed. Best for single rooms (bathroom, kitchen, mud room) where you want fast warmth on demand.
What Flooring Works Over It
- Porcelain or ceramic tile: the gold standard. Conducts heat best, no expansion issues.
- Engineered hardwood: rated up to 82F subfloor.
- Rigid-core LVP / SPC: most brands rate to 82F.
- Polished concrete: the slab itself is the radiator.
- Avoid: solid hardwood, bamboo, thick carpet (insulates against the heat), and any flooring whose spec sheet does not explicitly list radiant compatibility.
Running Costs
Electric radiant runs about 12 to 25 watts per square foot. A 50 sq ft bathroom at $0.16/kWh for 8 hours per day works out to roughly $4 to $8 per month in winter. Hydronic systems paired with a high-efficiency boiler or heat pump can heat a whole house at 20 to 30 percent lower cost than forced-air gas, per US Department of Energy modelling (energy.gov).
Frequently Asked Questions
What flatness does the subfloor need?
The industry default is 3/16 inch deviation over a 10 foot span (about 5 mm over 3 metres). Floating floors, rigid-core LVP, and engineered hardwood all share that spec. Tile is stricter at 1/8 inch over 10 feet because thinset cannot bridge a wavy slab.
How long should materials acclimate on site?
48 hours for laminate and LVP, 7 to 14 days for solid and engineered hardwood (until plank moisture content is within 2 to 4 percent of the subfloor). Skip it and you risk gapping in winter or cupping in summer.
Does this work over radiant heat?
Most rigid-core LVP, engineered hardwood, and porcelain tile are radiant-heat rated up to about 82F (28C) at the subfloor. Solid hardwood and bamboo usually are not. Always confirm the manufacturer spec before laying.
Is it the same in the UK?
The product categories and installation rules are nearly identical. UK retailers like B&Q, Wickes, Carpetright, and Topps Tiles carry the same Shaw / Mohawk / COREtec equivalents with British Standard labelling (BS EN 13329 for laminate, BS EN ISO 10874 for resilient flooring).
Pro Tips From the Trade
- Order 10 percent waste. Bump to 15 percent on diagonal layouts, herringbone, or rooms with lots of cutouts. Future repair planks need the same dye lot.
- Photograph the install. Subfloor, vapour barrier, expansion gaps, transitions. Warranty claims hinge on documentation.
- Keep one full carton. Same production run, stored flat in conditioned space. It is the only colour-true repair source you will ever have.
- Run planks toward the light. Parallel to the longest wall or toward the main window so seams disappear instead of catching shadows.
- Test moisture. Tape a 2 ft square of plastic to a concrete slab for 72 hours; condensation underneath means a moisture problem to solve before any flooring goes down.
Bottom Line
The product matters less than the prep. A flat, dry, clean subfloor with correct underlayment and proper acclimation will make a mid-priced floor outperform a premium one installed badly. Get those four basics right, follow the manufacturer's spec sheet, and you will not see a single one of the common failure modes (cupping, gapping, lifting, telegraphing) in the first decade.
Quick Buying Checklist
- Confirm the warranty covers your install type (residential vs commercial, DIY vs professional). Most manufacturers void the warranty if a non-certified installer skips moisture testing or acclimation.
- Buy 10 to 15 percent extra from the same production lot. Future repair planks have to match dye and texture exactly.
- Match the underlayment to the product. Wrong foam (too thick or too soft) is the #1 reason click joints fail in year two.
- Plan transitions at every doorway. Reducers, T-mouldings, and stair nosings are easy to forget and three times more expensive after the fact.
- Photograph the subfloor before the new floor goes down. Most warranty claims are denied for lack of install documentation.
Cross-reference the manufacturer's installation guide against the National Wood Flooring Association (NWFA) install best practices before you start. Mismatches between the two are common, and the manufacturer guide wins for warranty purposes but the NWFA guide wins for long-term durability.
