BTU Meter

A BTU meter — sometimes called an energy meter or heat meter — measures the thermal energy transferred in a heating or cooling system by combining flow measurement with supply and return temperature measurement. The result is a real-time BTU/hr reading and a running total of energy consumed, in BTU, kWh, or ton-hours.

BTU meters are used in chilled water systems for cooling energy submetering, in hot water systems for heating energy allocation, and in steam systems for process heat accounting. They're the foundation of any serious building energy management program and are required for tenant submetering in many commercial buildings.

How BTU measurement works

A BTU meter consists of three components: a flow meter, a supply temperature sensor, and a return temperature sensor. The flow meter measures how much water is flowing. The temperature sensors measure the difference between supply and return temperature. The energy calculation is: BTU/hr = flow rate (GPM) × ΔT (°F) × 500 (for water).

Our clamp-on ultrasonic flow meter is ideal for BTU metering because it installs without cutting the pipe — sensors clamp onto the outside of existing pipe, making it practical for retrofit installations in occupied buildings where shutting down the chilled or hot water system isn't acceptable.

Common BTU meter applications

• Chilled water submetering — measure cooling energy delivered to individual tenants, floors, or zones in commercial buildings

• Hot water submetering — measure heating energy for tenant billing in multi-tenant buildings and campuses

• District energy metering — measure energy delivered from central plant to individual buildings on a campus

• Heat exchanger performance monitoring — measure energy transferred across heat exchangers to detect fouling and efficiency loss

• Data center cooling — measure cooling energy consumed by server rooms and data halls

• Process heat accounting — measure thermal energy delivered to industrial processes for cost allocation

• LEED and energy certification — document building energy consumption for green building certification

What to look for when selecting a BTU meter

Pipe size and material determine ultrasonic meter compatibility. Clamp-on ultrasonic meters work on most pipe materials including carbon steel, stainless steel, copper, and most plastics. They don't work on heavily corroded pipe or pipe with significant scale buildup that blocks the ultrasonic signal. Pipe sizes from 1" to 48" are covered.

Temperature sensor type and installation — PT100 or PT1000 RTD sensors in immersion wells are the most accurate. Clamp-on surface temperature sensors are less accurate but easier to install. For billing-grade BTU metering, immersion sensors are preferred.

Output and integration — the flow meter outputs 4-20 mA, pulse, and Modbus RTU. For BTU calculation, an external BTU calculator, building management system, or our Cloud Data Logger combines the flow and temperature inputs into energy readings.

Accuracy — clamp-on ultrasonic accuracy is ±1% of reading for flow. Combined with ±0.1°C temperature accuracy, total energy measurement accuracy is typically ±2-3%. For tenant billing applications, verify this meets your local metering code requirements.

Application	Recommended Meter	Why
Retrofit BTU metering, 1" to 48"	Clamp On Ultrasonic + temp sensors	No pipe cutting, installs in hours
New installation, high accuracy	Inline MAG or Ultrasonic + temp sensors	Higher flow accuracy for billing-critical applications
Steam energy metering	Multivariable Vortex Flow Meter	Built-in P&T compensation, direct BTU output for steam
Data logging, energy reporting	Any meter + Cloud Data Logger	Automated energy data collection and trend reporting

In stock and ready to ship

Clamp-on ultrasonic flow meters for BTU metering ship from Salinas, CA. Temperature sensors and mounting hardware are available. Contact us with your pipe size, pipe material, and flow range.

Call us at (831) 244-8080 to talk through your application, or go straight to the product page to configure and order.

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