Quick verdict
For most everyday walkthroughs, the Multi-Function Environmental Meter is the practical default: a set of commonly needed readings in one unit. For work that depends on a specialized measurement, the testo 400 Smart is the instrument to pick, provided you're okay with the tradeoffs. Use the comparison below to confirm which measurement lineup matches your routine.
Comparison at a glance
| | Multi-Function Environmental Meter | testo 400 Smart |
| Listed price | $85.99 | $1,400 |
| Price gap | about $1,314 | - |
| Condition | New | Used |
| Measurement lineup | Anemometer, sound, air flow, humidity & LUX | Smart multi-function with PMV |
| Notable details | Tripod mount, dual LCD, ABS plastic and rubber | Testo, MPN 400 |
Where each product wins
Where the Multi-Function Environmental Meter wins
It gives you a full suite of everyday readings in a single unit, so you don't need separate devices for light, sound, and air movement. The tripod mount and dual LCD make it easy to compare values side by side. It's a much lighter investment, so it's the sensible default if you don't need the specialized metric.
Where the testo 400 Smart wins
This meter is the one to pick when the job calls for PMV measurement. The Testo name and MPN 400 identify it clearly as a more capable instrument for that specific kind of work.
Product notes
Multi-Function Environmental Meter
The Multi-Function Environmental Meter is a practical pick because it pairs an anemometer, sound meter, air flow meter, humidity sensor and LUX sensor in one product. The built-in precision humidity and temperature sensor plus the photo diode light sensor cover the basic indoor checks most people care about. A tripod mount and large dual LCD let you see two values at once, and the low-friction vane wheel improves air velocity readings. The tradeoff is specialized comfort-index work: this meter doesn't include a thermal comfort index among its five listed measurements, so comfort studies would need another tool. If five everyday readings are enough, this is the option that keeps the entry cost low.
testo 400 Smart
The testo 400 Smart is the specialized instrument in this head-to-head. It's a used unit, and it comes from Testo with MPN 400. What you get is a smart multi-function environmental meter designed around a comfort-index reading. That makes it the right choice when your workflow requires a thermal comfort index rather than just general readings. The limitation is that it's used, so it carries more uncertainty than a new meter. It makes sense only when that specialized comfort capability is actually part of your work.
Final choice by use case
Choose the Multi-Function Environmental Meter for routine indoor checks where you want to measure air velocity, sound, air flow, humidity and light in one unit without a heavy investment. Choose the testo 400 Smart when your readings include the specialized measurement highlighted above and you can accept the tradeoffs. For most shoppers, the multi-function meter is the practical default; for specialists, the Testo 400 Smart is the targeted pick.
