Installing radiant heat
These bright orange plastic pipes will soon have warm water flowing through them, producing luxurious comfort on winter days. Credit: Tim Carter
Floors, especially concrete ones, can be cold and uncomfortable in the winter.
With radiant heating, the entire floor - or different sections or zones of the floor - becomes vast heating pads, transmitting the heat from the boiler to you. The heat is even, and the concrete acts like a massive heat sink or storage vessel. The amount of heat is controlled by a standard thermostat.
Most homes that have radiant heat provide an added benefit.
A room or group of rooms is put into a zone controlled by a separate thermostat. This allows you to use energy wisely, as you can easily set parts of your home at different temperatures. When you're not in a room or rooms, automatic setback thermostats can lower the temperature to save money. The zoning feature allows you to send heat to the rooms only when you're in them. It's a clever system, and most radiant-heating contractors are good at setting up zones that make sense for your lifestyle.
You can have subfloor radiant heat in just about any home.
If you're building new with a standard wood-frame home, you can have a wood-floor radiant-heat system. The plastic tubing is affixed to the underside of the wood floor or set very close to the underside of the wood sheathing that covers the floor joists.
Recently, there's been growth in smaller systems that work well in remodeling situations, such as bathrooms and kitchens with tile floors. The thin electric mats create tile-floor radiant heat that feels just the same as that created by a whole-house boiler. Be sure to do the math before you think about using electric radiant heat in your entire home. It may be more costly to operate over time.
It's even possible to have a hardwood-floor radiant-heat system.
Hardwood-flooring manufacturers over the past few years have worked in conjunction with the radiant-heating industry to develop standards that allow gorgeous hardwood floors to be installed just above the subfloor radiant- heat piping. When done correctly, the hardwood floor does not develop unsightly cracks between each piece of flooring from extreme expansion and contraction.
With concrete floor radiant heat, it's important to insulate underneath.
Insulation beneath the floor blocks the heat from soaking into the earth beneath your home. Rigid foam insulation is typically placed on top of compacted granular fill material. After the foam is in place, it's covered with a high-performance vapor barrier that prevents soil moisture from invading your basement, making it damp and moldy.
Contractors often include welded-wire steel reinforcing mats as part of the installation.
These are a great idea. They not only strengthen the concrete and ensure that cracks don't grow and put stress on the plastic heating tubes, but also help hold the plastic tubing in place during the concrete pour. The plastic tubes are attached to the steel fabric, often in parallel strips one-foot apart.
