USA
Canada
A whole house radiant heating system heats every room through the floors, walls, or ceilings rather than through forced air ducts or perimeter baseboard units. The result is a home where every surface is part of the heating system, every floor is warm to walk on, and every room maintains an even, consistent temperature without drafts, cycling noise, or air movement.
WBI has designed and supplied whole-home hydronic radiant systems for four decades. Here is how a complete system is structured, how it is sized, and what makes it worth the investment for the right homeowner.
What Makes It a Whole House System
A whole house hydronic radiant system has three layers: the heat source, the distribution network, and the terminal zones. The heat source is a boiler or heat pump that produces hot water. The distribution network carries that water through insulated piping to a central manifold, which splits flow into individual zone circuits. Each circuit serves a floor area, a wall panel, or a ceiling panel in one zone of the home.
Every zone has its own thermostat. A bedroom can hold 65 degrees Fahrenheit while the main living area stays at 70. A guest room that is rarely occupied runs at a minimum setpoint and ramps up when needed. The boiler or heat pump runs only when one or more zones call for heat, and the manifold zone valves direct flow only to those zones. The rest of the system is idle, retaining whatever heat remains in the slab or panel mass.
Zoning Strategy for a Whole Home
Zone layout is one of the most consequential decisions in a whole-home radiant design. Group zones incorrectly and the system either runs zones that do not need heat or leaves zones that do need it undersupplied. WBI designs zone layouts based on three factors: floor plan, solar exposure, and occupancy schedule.
South-facing rooms with large windows receive significant solar heat gain on clear winter days and may not need active heating for hours at a time. They belong in their own zone rather than being lumped with north-facing rooms that need continuous heat. Bedrooms used only at night can set back to lower temperatures during the day without affecting the main living areas. Bathrooms, which are used briefly but benefit from warm floors, are often grouped with adjacent hallways in a single zone.
A typical 2,000 to 3,000 square foot home works well with 5 to 8 zones. Larger homes with complex floor plans or significant exposed glazing may use more. WBI calculates the zone count and layout as part of each system design.
Heat Source Selection for Whole House Radiant
The heat source for a whole-home radiant system is chosen based on available fuel, budget, local utility rates, and the supply water temperature the distribution system requires. Radiant floor systems are particularly well suited to low-temperature heat sources because floor panels deliver full comfort output at 85 to 110 degrees Fahrenheit, well within the optimal operating range of both condensing gas boilers and hydronic heat pumps.
A hydronic heat pump paired with a buffer tank is the most efficient whole-home heat source available today in most climates. Modern cold-climate heat pumps deliver water at 120 degrees Fahrenheit at outdoor temperatures as low as minus 13 degrees Fahrenheit. At the 95 to 100 degree supply temperatures a well-designed radiant floor requires, a heat pump achieves a coefficient of performance of 3.5 to 4.5, meaning 3.5 to 4.5 units of heat for every unit of electricity consumed. Over a heating season in a cold climate, this translates to 55 to 65 percent lower energy cost compared to electric resistance heating.
A high-efficiency condensing gas boiler is the right choice where natural gas is available and affordable and where an all-electric system is not the goal. At the low return water temperatures that radiant floors produce, a condensing boiler recovers latent heat reliably and operates at seasonal efficiency above 90 percent AFUE. WBI sizes the boiler to the calculated heating load of the building, not the square footage, because oversized boilers short-cycle and operate at reduced efficiency.
Tubing Layout Across the Whole House
Each zone in a whole-home radiant system has one or more tubing circuits connected to the central manifold. The manifold is typically located in a mechanical room, utility closet, or basement, with supply and return lines running through the floor or wall assembly to each zone. Flow balancing valves on each manifold port allow the installer to set equal flow rates across all circuits regardless of their length, which is essential for even heat distribution across the home.
Circuit lengths are kept within the recommended maximum for the tubing diameter used, typically 300 feet for half-inch PEX. Rooms larger than the single-circuit coverage area are split into multiple circuits, each on its own manifold port. WBI designs circuit layouts with all loops within 10 percent of each other in length, which keeps balancing straightforward and the system even throughout.
Controls: Making the Whole System Work Together
A whole-home radiant system benefits from controls that go beyond a thermostat in each zone. Outdoor reset control adjusts the supply water temperature based on outdoor air temperature, reducing it on mild days and increasing it during cold snaps. This keeps the distribution system operating at the lowest temperature that satisfies the load, which maximizes heat pump efficiency and condensing boiler efficiency simultaneously.
Multi-zone thermostats with scheduling allow each zone to follow the household’s actual occupancy pattern. A home where most rooms are unoccupied from 8am to 5pm saves meaningful energy by setting back those zones during the day, particularly in the bedrooms and office zones. WBI specifies controls that are appropriate for the complexity of each system, from simple single-zone thermostats to multi-zone smart controllers with outdoor reset and scheduling.
Frequently Asked Questions About Whole House Radiant Heating
Design Your Whole House Radiant System with WBI
WBI has designed and supplied whole-home hydronic radiant systems across North America for decades. Share your floor plan and construction details and we will put together a complete system design.
About The Author
