How much does it cost to install radiant floor heating in a new addition in Ottawa?

Radiant floor heating is one of the most comfortable ways to heat a new addition, especially with winters that regularly reach well below -20°C. The cost depends mainly on whether you choose a hydronic (water-based) or electric system, and on the size of the addition.

Electric radiant heat uses heating cables or mats under tile, laminate or engineered flooring. It is simpler to install in new construction, because the mats go down over the subfloor before the finished floor. Installation cost is usually lower than hydronic, but operating cost can be higher, because you are heating with electricity on your utility's rates. It is often a good fit for smaller rooms or for a floor-warming layer in a bathroom.

Hydronic radiant heat circulates warm water through PEX tubing in the slab or in a thin layer over the subfloor. It is usually the more efficient choice for larger spaces but costs more to install, because it needs tubing, a manifold, pumps, controls and a heat source. If the addition is far from your existing mechanical room, or your existing equipment can't supply it, a new boiler or other heat source may be part of the job. Any gas-fired boiler is installed by a TSSA-certified gas technician.

Slab or joists. Radiant heat pairs especially well with slab-on-grade additions, because the concrete stores heat and evens out temperature swings. For additions built over a crawlspace or joists, tubing can be suspended or installed with heat transfer plates under the subfloor, which adds material and labour.

Insulation under the floor. A heated slab loses heat into the ground unless it is insulated underneath. Ask your designer what insulation and vapour barrier the drawings call for under the slab, and make sure it is in the contractor's quote. The addition's overall energy compliance falls under SB-12, which requires a compliance package or the addition table.

Sizing. A heat-loss calculation tells you how much heat the addition needs and whether radiant floors alone can carry it on the coldest days or need backup.

Electrical. Electric systems need a dedicated circuit, and a large installation may need panel capacity checked. That work needs an ESA notification and is done by an ESA-licensed electrical contractor.

Ask for itemized quotes that separate the heat source, distribution, controls and flooring so you can compare systems. You can browse addition contractors with radiant heating experience in the Ottawa Construction Network directory at justynrookcontracting.com.

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Looking for experienced contractors? The Ottawa Construction Network connects homeowners with qualified professionals:

• 613Bins
• JC Carpentry
• Vanguard Environmental
• Ottawa Caulking
• JMY Renovations