7.2 Thermal Zoning (T03), Radiant Thermal Comfort (T05) & Thermal Comfort Monitoring (T06)
Key Takeaways
- T03 Thermal Zoning requires thermostat or digital interface control in at least 90% of regularly occupied spaces, with each thermal zone no larger than 650 ft2 (60 m2) or 10 occupants, whichever is larger.
- T03 awards 1 point for one zone per 650 ft2 (60 m2) or per 10 occupants, and 2 points for one zone per 320 ft2 (30 m2) or per 5 occupants.
- T03 requires temperature sensors to sit at least 3.3 ft (1 m) from exterior walls, windows, doors, direct sunlight, air supply diffusers, fans, heaters or other significant heat or cold sources.
- T05 Radiant Thermal Comfort awards 1 point each for radiant heating and radiant cooling covering at least 50% of the regularly occupied project area.
- T06 Thermal Comfort Monitoring requires dry-bulb temperature and relative humidity sensors at one per 3,500 ft2 (325 m2), mounted 3.6 to 5.6 ft (1.1 to 1.7 m) above the floor, sampling at least every 15 minutes.
7.2 Thermal Zoning (T03), Radiant Thermal Comfort (T05) & Thermal Comfort Monitoring (T06)
Core Exam Takeaway: T03 Thermal Zoning (2 pt / Core 3 pt) uses the same granularity ladder as L09 lighting zones — 650 ft² (60 m²) or 10 occupants for the first tier, 320 ft² (30 m²) or 5 occupants for the second. T05 Radiant Thermal Comfort (2 pt / Core 4 pt) pays 1 point each for radiant heating and radiant cooling at 50% of regularly occupied area. T06 Thermal Comfort Monitoring (1 pt / Core 0.5 pt) is the sensing feature that T01 Option 2 and T07 Option 3 both require.
Feature T03: Thermal Zoning — Optimization (2 pt / WELL Core 3 pt)
Intent: enhance thermal comfort through thermal zoning, allowing control of either the conditions of a thermal zone or movement between thermal zones.
T03 Part 1 — Provide Thermostat Control
All requirements apply to at least 90% of regularly occupied spaces:
- (a) Control over temperature is available through either thermostats present within the thermal zone or a digital interface accessible to occupants on a computer or phone.
- (b) The maximum size of each thermal zone is 650 ft² (60 m²) or 10 occupants, whichever is larger.
- (c) Points by zone count:
| Number of zones | OR | Number of zones | Points (Core) |
|---|---|---|---|
| One per 650 ft² (60 m²) | OR | One per 10 occupants | 1 (2) |
| One per 320 ft² (30 m²) | OR | One per 5 occupants | 2 (3) |
- (d) Temperature sensors are positioned at least 3.3 ft (1 m) away from exterior walls, windows and doors, direct sunlight, air supply diffusers, mechanical fans, heaters or any other significant sources of heat or cold.
WELL Core guidance: whole building.
[!IMPORTANT] Requirement (b) is a ceiling, and (c) is a scoring ladder — two different mechanisms in one part. Even at the 1-point tier, no zone may exceed 650 ft² (60 m²) or 10 occupants, whichever is larger, so a project cannot average its way to compliance with one enormous zone offset by several tiny ones.
[!TIP] Sensor placement (d) is the most physically consequential requirement and the most testable. A thermostat mounted beside a west-facing window reads solar gain, not room temperature, and drives the whole zone into overcooling. The 3.3 ft (1 m) standoff from exterior walls, glazing, doors, direct sun, diffusers, fans and heaters recurs almost verbatim in T06 Part 1 Option 1(a) and in A06's CO₂ sensor rules — one distance, three features.
[!TIP] T03 and L09 share an architecture. Both use 650 ft² (60 m²) / 10 occupants then 320 ft² (30 m²) / 5 occupants, and both accept either an area test or a headcount test as alternatives. Learning the ladder once serves both concepts — and a project laying out lighting and HVAC zones on the same grid earns both features from one coordination exercise.
Feature T05: Radiant Thermal Comfort — Optimization (2 pt / WELL Core 4 pt)
Intent: maximize volume of the space, reduce dust transmission, improve ventilation control and increase thermal comfort by incorporating radiant heat and cooling systems.
T05 Part 1 — Implement Radiant Heating (1 pt / Core 2 pt)
At least 50% of the regularly occupied project area is heated with one or more of:
- (a) Radiant ceilings, walls or floors
- (b) Radiant panels which cover at least half of the wall or ceiling to which they are attached — does not include steam radiators
T05 Part 2 — Implement Radiant Cooling (1 pt / Core 2 pt)
At least 50% of the regularly occupied project area is cooled with one or more of:
- (a) Radiant ceilings, walls or floors
- (b) Radiant panels that cover at least half of the wall or ceiling to which they are attached
WELL Core guidance for both parts: whole building; up to 10% of the total tenant-occupied area may be excluded from feature scope.
[!IMPORTANT] Steam radiators are explicitly excluded from Part 1's panel option. A wall-mounted steam radiator is a convector — it heats by moving air, not by radiant exchange with occupants — so it delivers none of the feature's intended benefits.
Why radiant systems earn a feature of their own
Recall that mean radiant temperature is one of the six ASHRAE 55 variables, and that occupants exchange heat with surfaces regardless of air temperature. Radiant systems act directly on MRT, which yields four benefits WELL names in the intent:
- Comfort at a wider air-temperature range, because a warm floor compensates for cooler air.
- Reduced dust transmission, because there is no high-velocity air stream re-entraining settled particulate.
- Improved ventilation control, because ventilation air can be sized for air quality alone rather than for heating and cooling loads — which pairs directly with A06 Part 2's displacement ventilation and A13's 100% outdoor air option.
- Maximized space volume, because ductwork shrinks when air is no longer the heat-transfer medium.
[!WARNING] Radiant cooling requires careful dew-point control — chilled surfaces below the dew point condense. That is the engineering reason projects pursuing T05 Part 2 almost always also pursue T07 Humidity Control, and why a Dedicated Outdoor Air System handling latent load is the usual companion.
Feature T06: Thermal Comfort Monitoring — Optimization (1 pt / WELL Core 0.5 pt)
Intent: monitor and effectively address unacceptable thermal comfort conditions and inform building managers and users of thermal comfort parameters.
T06 Part 1 — Monitor Thermal Environment
Option 1: Thermal comfort monitors. The project monitors dry-bulb temperature and relative humidity, with:
- (a) Sensors located in occupiable areas; 3.6–5.6 ft (1.1–1.7 m) above the floor; and at least 3.3 ft (1 m) away from exterior walls, doors, direct sunlight, air supply/exhausts, mechanical fans, heaters or any other significant source of heat or cold.
- (b) A minimum of one sensor per 3,500 ft² (325 m²) of occupiable floor area.
- (c) Measurements taken at least once every 15 minutes.
- (d) Sensors comply with the Device Requirements in the WELL Performance Verification Guidebook.
Option 2: Reporting & maintenance.
- (a) Data are submitted annually through the WELL digital platform.
- (b) Sensors are recalibrated or replaced at least every three years, with certificates submitted every three years.
Option 3: Environmental measures display. Real-time display of dry-bulb temperature and relative humidity available to occupants through either:
- (a) Display screens, at least one per 3,500 ft² (325 m²) zone of regularly occupied space; or
- (b) A website or mobile application, with at least one sign per 3,500 ft² (325 m²) zone indicating where the data may be accessed.
WELL Core guidance: non-leased spaces; displays in tenant-accessible areas or otherwise available to tenants; an additional point for also meeting requirements in leased spaces.
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| T06 IS THE CONCEPT'S LOAD-BEARING FEATURE |
| |
| T01 Part 1 Option 2 (long-term thermal data) ---requires--> T06 |
| T01 Part 2 Option 2 (continuous monitoring) ---requires--> T06 |
| T07 Part 1 Option 3 (long-term humidity data) ---requires--> T06 |
| |
| T06 itself is worth only 1 point -- but it unlocks the easiest |
| compliance route for the PRECONDITION and for humidity control. |
| Buy the sensors first. |
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[!TIP] Note the calibration cadences differ across concepts: T06 requires recalibration or replacement at least every three years, whereas A08 Part 1 Option 2 requires air quality monitors to be recalibrated or replaced annually. Air sensors drift faster than temperature and humidity sensors, and WELL's cadences reflect that.
[!IMPORTANT] The 3,500 ft² (325 m²) module appears in T06 Options 1 and 3 exactly as it does in A01 Part 2 Option 2, A08 Parts 1 and 2, and L09's zone ladder neighbours. WELL reuses a small set of spatial modules deliberately — 3,500 ft² (325 m²) for sensing and display, 650 ft² (60 m²) and 320 ft² (30 m²) for control zones.
An open office of 6,400 ft² with 40 occupants wants the maximum 2 points from T03. What zoning satisfies the requirement?
Where must temperature sensors be located under T03 Part 1(d)?
A project heats 60% of its regularly occupied area with radiant floors and cools 40% with radiant ceiling panels covering two-thirds of each ceiling. How many points does T05 award?
Which sensor configuration satisfies T06 Part 1 Option 1?