Choosing the right version of an ESP32 board is an important step in developing smart home or smart city projects. Many IoT project developments stumble not because of poor coding or lack of vision, but because a board chosen early on doesn’t align with the realities of large-scale deployment. One smart parking pilot, for example, projected five years of battery life per sensor — but the ESP32 variant used wasn’t optimized for ultra-low-power duty cycles. In practice, batteries needed replacing every 18 months, turning a promising business case into an unsustainable one. Small mismatches like this can snowball into rising project costs and extended time-to-market.

That’s why understanding the ESP32 board family itself is so important. The Espressif ESP32 is a low cost, powerful SoC (System-on-Chip) that has become a popular choice for Internet of Things devices. An SoC integrates a processor, memory, wireless connectivity (Wi-Fi, Bluetooth and more), and various peripherals onto a single chip. This high level of integration simplifies the design of connected devices, significantly reducing their size, complexity, and cost. ESP32 initially launched as a single chip, the ESP32 family has expanded into a diverse series of variants, each tailored for different applications, from simple smart home gadgets to complex industrial systems.

What are ESP32 variants?

The ESP32 family is divided into several series, each targeting different projects needs based on performance, power consumption and cost. We can start with The S-Series (S2, S3): which is the high-performance line, built on the Tensilica Xtensa processor architecture. The ESP32 S-line offers great performance at a relatively low price (€2–3). Equipped with WiFi and BLE (S3) and one of the highest pin counts in the entire EPS32 family makes the ESP32 S-line the most common choice when designing a device, as it is simply the most versatile chip.

Next we have the ESP32-C3 which is optimized for low-power devices requiring wireless communication. Lower performance and fewer GPIO (General-Purpose Input/Output) pins are compensated for by one of the lowest prices (€1–2) compared to the rest of the ESP family. For future proof IoT solutions you should consider the ESP32-C6 as your design choice. It offers WiFi 6, Bluetooth 5 and most importantly: the 802.15.4 standard, which is the basis for Thread and Zigbee protocols. This is a big advantage considering the growing popularity of the Matter standard.

On the other hand the H series offers wireless connectivity specialized for building automation and industrial applications (802.15.4 Zigbee, Thread, and BLE), It has hardware security features (secure boot, encryption). The RISC-V core features low power consumption, allowing these microprocessors to be used in battery-powered devices.

And the last available ESP variant is ESP32-P series, a high-performance computing platform  with a focus on HMI (human-machine interface) and edge processing applications. Unlike the other ESP32 microcontrollers, it lacks wireless connectivity (Wi-Fi and Bluetooth) to instead focus on computational power and a rich set of peripherals. It supports high resolution cameras and displays including H.264 encoding support. With a dual-core RISC-V processor clocked at up to 400 MHz and 768 KB of built-in SRAM, this microcontroller is the most powerful in the esp32 family.

Which ESP32 board is best for a smart home project?

For smart home projects, the primary requirements are Wi-Fi connectivity, low cost, and ease of development. The ESP32-S3 stands out as the best all-around choice: its powerful dual-core processor and large number of GPIO pins make it versatile enough for a wide range of applications.

 

When working with tighter budgets, the ESP32-C3 is an excellent alternative. It is well-suited for single-purpose devices such as smart meters, plugs, or sensors, and comes at a lower price point.

 

Some projects, however, demand long battery life. In these cases, the choice of board can be even more critical than the SoC itself. Certain boards integrate LiPo charging and power management circuits, while standard development kits often drain batteries quickly due to less efficient components. To maximize battery life, manufacturers use optimized designs around low-power chips – and here again, the ESP32-C3 shines thanks to its strong energy efficiency.


Finally, if future-proofing is a priority, the ESP32-C6 is the board to consider. With support for both Zigbee and Thread, it is fully aligned with the emerging Matter smart home standard, ensuring long-term compatibility and keeping your devices relevant as smart home ecosystems evolve.

Which ESP32 board is best for a smart city project?

Smart city applications operate on a much larger scale and in harsher environments, making Wi-Fi unsuitable. These projects require long-range, low-power communication and hardware that can withstand suboptimal working conditions.

For Long-Range Communication we recommend using LoRaWAN or Cellular endpoints. The most effective approach is to use boards designed specifically for these technologies. For LoRaWAN, this typically involves an integrated development board that combines an ESP32 SoC, such as ESP32-S3 or C3 if it is an energy constrained device with LoRa transceiver on a single PCB. This approach simplifies development and is a common, reliable solution that uses ESP32 for processing. 

Why LoRaWAN?

LoRaWAN is a strategic choice when ultra-low operational costs (OPEX) are a priority. Devices can run on a single battery for 5–10 years, drastically cutting maintenance by avoiding frequent replacements across thousands of deployed sensors (e.g., parking meters, water meters, or waste bins). The ability to build a private network with just a few gateways eliminates monthly subscription fees, while even public carrier options remain far cheaper than cellular. With a single gateway covering several kilometers in urban areas, infrastructure requirements drop significantly – reducing costs and simplifying large-scale deployments.

While using cellular communication, the solution involves pairing a capable ESP32 board (for example, ESP32-S3) with a dedicated external cellular modem module, as this provides necessary LTE Cat-M1 or NB-IoT connectivity.

Why use LTE (Cat-M1/NB-IoT)?

Cellular technologies like LTE Cat-M1 and NB-IoT are ideal when the priority is fast time-to-market and guaranteed reliability. The manufacturer does not need to invest in building and maintaining its own network of gateways. Devices connect to the existing, professionally managed infrastructure of cellular operators. This significantly lowers the barrier to entry and initial investment costs. Using a cellular network provides a high quality of SLA (Service Level Agreement), security, and nationwide coverage “out of the box.” This makes it easy to scale the business from one city to an entire country without additional infrastructure investments. Also the operational costs (data subscription) can easily be included in a subscription model for the end customer. This is a perfect solution for mobile assets (e.g., e-scooters, city bikes) or where building a private network is impractical.

The other option for smart city projects is usage of mesh networks (Thread/Zigbee). In this type of use case we recommended using ESP32-C6. It is a great choice for a gateway device that bridges the mesh network to the internet via Wi-Fi. For individual nodes within the mesh, the ESP32-H2 is the optimized, low-power choice.

Why use a mesh network (Thread/Zigbee)?

Mesh networks are an excellent choice for projects with a high density of devices in a confined area, such as smart street lighting or building energy management systems. Like a private LoRaWAN network, they operate independently, eliminating data transmission costs and giving full control of the infrastructure to the solution owner.

They are also highly resilient: if one node (e.g., a streetlight) fails, data will automatically reroute through neighboring nodes to reach the gateway. From an investor’s perspective, this translates into greater system reliability and lower maintenance costs.

Finally, the cost of radio modules for individual nodes (such as the ESP32-H2) is very low, making it feasible to deploy networks with hundreds or even thousands of devices while keeping hardware budgets under control.

Use Cases for Smart Home Projects?

  • Unified Home Control Hub: A central touchscreen panel or voice assistant that manages lighting, thermostats, and smart blinds. This hub can analyze energy usage patterns to suggest savings. An ESP32-P4 is great for the main hub due to its processing power and rich peripheral support, while ESP32-C6 nodes can control individual devices over a Thread mesh network.
  • Automated Security & Access Control: A system integrating door/window sensors, smart locks, and indoor cameras. It can grant temporary access to guests via a mobile app and send real-time alerts with snapshots if an anomaly is detected. An ESP32-S3 with camera support is perfect for a video doorbell, while battery-powered ESP32-H2 sensors can run for years on a Thread network.
  • Intelligent Appliance Management: A network that connects your appliances, allowing you to pre-heat your oven from your phone, get a notification when the laundry is done, or automatically re-order dishwasher tablets. The reliable Wi-Fi 6 and Bluetooth 5 connectivity of the ESP32-C6 makes it a solid choice for individual appliance modules.

Use Cases for Smart City Projects?

  • Intelligent Waste Management: Sensors inside public trash bins monitor fill levels and automatically notify the sanitation department when they are ready for collection. This optimizes collection routes, saving fuel, time, and labor costs. This use case is ideal for an ESP32-C3 paired with a LoRaWAN module for long-range, low-power communication.
  • Intelligent Public Transit Management: Equip buses and trams with systems that perform real-time passenger counting. This data allows for dynamic route optimization based on actual demand and enables predictive maintenance, reducing breakdowns and improving service reliability. An ESP32-S3 is powerful enough for this task, using a cellular LTE-M modem to provide constant connectivity for the mobile assets.
  • Urban Noise Pollution Monitoring: A distributed network of low-cost sound level sensors provides a real-time map of noise levels across the city. This helps city officials enforce noise ordinances, assess the impact of construction projects, and plan quieter public spaces for improved citizen well-being. The low data-rate and wide area coverage needs are perfectly met by using an ESP32 with a LoRaWAN module, allowing for a cost-effective, large-scale sensor deployment.

Comparison Table

Feature ESP32 (Classic) ESP32-S2 ESP32-S3 ESP32-C3 ESP32-C6 ESP32-H2
CPU Core
Dual-Core
Single-Core
Dual-Core
Single-Core
Single-Core
Single-Core
Architecture
Xtensa LX6
Xtensa LX7
Xtensa LX7
RISC-V
RISC-V
RISC-V
Max Clock (MHz)
240
240
240
160
160
96
SRAM (KB)
520
320
512
400
512
320
ROM (KB)
448
128
384
384
320
128
Wi-Fi Protocol
Wi-Fi 4
Wi-Fi 4
Wi-Fi 4
Wi-Fi 4
Wi-Fi 6
no
Bluetooth
Classic & BLE 4.2
No
BLE 5.0
BLE 5.0
BLE 5.3
BLE 5.3
802.15.4
No
No
No
No
Yes
Yes
GPIOs (Max)
34
43
45
22
30
19
ADC Channels
18 (12-bit)
20 (13-bit)
20 (13-bit)
6 (12-bit)
7 (12-bit)
Supported

Conclusion

The ESP32 board ecosystem offers a powerful and flexible platform for IoT development, but there is no single “best” board. The optimal choice is entirely dependent on the specific requirements of the project. For smart home applications, where Wi-Fi is ubiquitous and cost is a key factor, variants like the ESP32-S3, C3, and C6 provide excellent solutions, with success often hinging on user-friendly software like ESPHome. In contrast, smart city applications must contend with challenges like long-range communication and energy autonomy. Here, specialized hardware and protocols such as LoRaWAN or Thread make integrated modules and chips like the ESP32-H2 and C6 essential.

That’s why making a strategic hardware decision early is critical to achieving both technical and business goals. If you’re unsure which ESP32 board best fits your project, our team has years of hands-on experience working with the entire family of modules – and we’re happy to help you choose the right solution.