What factors affect the price of a transformer oil tester?

Price depends on the test functions included, accuracy class, standards compliance, automation features, safety interlocks, data logging, calibration support, and ruggedness for field use. A simple BDV tester is usually cheaper than a combined kit measuring moisture, tan delta, resistivity, or portable DGA screening. Brand reputation, service network, warranty, and certification also influence cost, as does whether the unit is intended for lab or harsh substation environments.