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#thermal balance point

Tech Tips:

Thermal Balance Point vs. Economic Balance Point

The thermal balance point is the point at which a heat pump can move heat into the home at the same rate the home loses its heat. Above this point, the heat pump will not need any additional help to heat the home. But below it, the heat pump will need auxiliary heat with it […]

Thermal Balance Point

Thermal balance point is a concept that is going to start mattering a lot more in years to come as more and more homeowners become interested in electrification. In almost all cases, the heat load for a house is larger than the cooling load; this is true even where I live in Dallas, Texas. Why […]

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Real training for HVAC ( Heating, Ventilation, Air Conditioning and Refrigeration) Technicians. Including recorded tech training, interviews, diagnostics and general conversations about the trade.

In this short podcast episode, Bryan breaks down the differences between a thermostatic expansion valve (TXV) and an electronic expansion valve (EEV). He highlights their strengths and weaknesses.

In the basic refrigerant circuit, the metering device drops the pressure. TXVs and EEVs are both metering devices that cause the liquid refrigerant to drop in pressure and become a liquid-vapor mixture; they control evaporator feeding and maintain a constant superheat.

TXVs achieve this by mechanical means; the bulb responds to suction line temperature and evaporator pressure at the valve. They are self-contained and easy to diagnose with basic refrigeration measurements. However, they are prone to mechanical failures, including clogged orifices and screens, cracked capillary tubes, and powerhead leaks. Installation errors are also easy to make, and TXVs can hunt in low-load conditions. Overall, failures are often mechanical and refrigerant-related. They win in the simplicity department.

EEVs receive inputs from sensors and modulate in response to those digital signals. They have a wider modulation range and maintain stable control in low-superheat applications, and they do well in conditions with highly variable loads or where coordination across multiple coils is required. EEVs come in two types: stepper motor (small, discrete steps) and PWM (controlled solenoid valves). Stepper-style EEVs excel at fine positioning, and PWM-style EEVs are in applications that require a more robust valve (like CO2 refrigeration). EEV failures are often electromechanical or related to sensor control. They win in the controllability department.

There is no “best” metering device; they merely have different strengths that make them better suited to different applications. However, EEVs are the future due to the greater degree of controllability we will need in newer equipment. Commissioning and airflow are also crucial for getting the most out of both metering device types in terms of longevity and reliability.

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TXV vs. EEV – Short #278

02/10/2026

Bryan Orr

Electric Heat Talk w/ Bert

02/05/2026

Bryan Orr