Imagine coming home to lights that adjust to your mood, thermostats that learn your schedule, and doors that lock themselves—all without lifting a finger. For many, this seamless smart home experience feels like a distant dream reserved for high-end setups. The truth? Getting started doesn’t require a hefty investment or technical wizardry. Budget-friendly hubs under $100 in 2026 are your gateway to this world, transforming isolated gadgets into a coordinated ecosystem. The key is knowing what truly matters for a starter setup, avoiding the pitfalls of overspending on features you won’t use or buying into a system that locks you into dead ends.
Navigating the sea of affordable hubs can feel overwhelming, especially when faced with buzzwords like Zigbee, Matter, and Thread. Many beginners make the mistake of grabbing the cheapest option only to discover it lacks critical compatibility or becomes obsolete within a year. Others overspend on advanced features designed for complex whole-home systems, draining their budget before they even add a single smart bulb. This guide cuts through the noise. We’ll focus solely on the essential criteria that matter right now for someone building their first smart home foundation—prioritizing flexibility, reliability, and future-proofing without blowing your $100 budget. Forget chasing specific brands; let’s build your knowledge foundation first.
Top 10 Smart Home Hubs
Detailed Product Reviews
1. Aeotec Smart Home Hub, Works as a SmartThings Hub, Z-Wave, Zigbee, Matter Gateway, Compatible with Alexa, Google Assistant, WiFi
Overview: The Aeotec Smart Home Hub serves as a dedicated SmartThings Hub for North American users, acting as a central nervous system for diverse smart home ecosystems. It bridges Z-Wave (V3 model), Zigbee, Matter, Wi-Fi, Alexa, and Google Assistant devices into a single, unified SmartThings platform, enabling comprehensive home automation without relying on multiple hubs.
What Makes It Stand Out: Its standout feature is exceptional protocol agnosticism, supporting Z-Wave Plus, Zigbee, Matter, and Wi-Fi natively within the SmartThings app. This eliminates compatibility headaches, allowing seamless integration of thousands of devices from disparate brands. Local automation execution ensures reliability even during internet outages, a critical advantage over cloud-dependent hubs.
Value for Money: Priced competitively against standalone Z-Wave or Zigbee hubs, it offers superior value by consolidating multiple hub functions into one device. While the SmartThings app is free, avoiding subscription fees for core automations, the North America-only certification limits its global appeal, slightly reducing value for international buyers.
Strengths and Weaknesses: Strengths: Broad protocol support (Z-Wave, Zigbee, Matter, Wi-Fi); robust local processing; easy SmartThings app integration; dual Wi-Fi/Ethernet setup. Weaknesses: Geographically restricted to North America; lacks built-in voice assistant (requires separate speaker); initial SmartThings setup can be complex for beginners.
Bottom Line: An indispensable hub for serious SmartThings users seeking reliable, local control over a mixed-protocol smart home. Its broad compatibility and local execution justify the cost, making it a top choice for North American enthusiasts prioritizing stability and integration depth over voice control.
2. Amazon Echo Hub, 8” smart home control panel, Designed for Alexa+, Compatible with thousands of devices
Overview: The Echo Hub is a wall-mountable touchscreen control panel designed exclusively for managing Alexa-compatible smart home devices. It functions as a central command station, replacing physical switches and app navigation with intuitive touch controls for lights, cameras, locks, and routines, positioned as the physical interface for an Alexa-centric home.
What Makes It Stand Out: Its dedicated, clutter-free dashboard for smart home control sets it apart. Customizable widgets let users prioritize critical functions (e.g., security system arming, camera feeds) for instant access. The seamless integration with Alexa+ and support for Matter, Thread, and Sidewink protocols ensure compatibility with nearly all modern Alexa devices without needing a separate hub.
Value for Money: Positioned as a premium convenience accessory, its value lies in simplifying complex smart home management. While not essential (controls exist via app/voice), it justifies its price for users wanting a permanent, glanceable control point, especially compared to repurposing a tablet. However, wall-mounting accessories sold separately add hidden costs.
Strengths and Weaknesses: Strengths: Intuitive, focused smart home dashboard; deep Alexa+ integration; supports Matter/Thread/Sidewalk; easy wall mounting; no separate hub needed. Weaknesses: Limited to Alexa ecosystem; no voice interaction (Alexa responses are text-only); requires power-over-ethernet/cable management for clean install; lacks entertainment features.
Bottom Line: An excellent investment for Alexa power users seeking a dedicated, always-visible smart home command center. Its streamlined interface and protocol support make complex setups manageable, though it’s redundant for those satisfied with voice/app control or non-Alexa ecosystems.
3. Amazon Echo Show 15 (newest model), Full HD 15.6" kitchen hub for home organization, with built-in Fire TV, Designed for Alexa+
Overview: The Echo Show 15 is a large-format smart display purpose-built as a kitchen and family command center. Its 15.6" Full HD screen showcases customizable widgets for calendars, recipes, and smart home controls, while integrating Fire TV for entertainment and Alexa+ for voice assistance, aiming to centralize household management.
What Makes It Stand Out: The massive screen size is its defining feature, enabling true “at-a-glance” utility for family organization (calendars, shopping lists) and kitchen tasks (video recipes). Unlike smaller models, it uniquely combines robust home organization tools with full Fire TV functionality and Active Media for multi-room audio, all optimized for wall or countertop placement.
Value for Money: As a premium all-in-one hub, it offers strong value by replacing multiple devices: a tablet for recipes, a smart display for video calls, and a streaming stick. The inclusion of Fire TV and family organization tools justifies its cost versus smaller Echo Shows, though subscription services (Netflix, etc.) are required for full entertainment use.
Strengths and Weaknesses: Strengths: Large, versatile 15.6" display; excellent family organization features; integrated Fire TV; customizable widgets; photo slideshow capability; strong kitchen utility. Weaknesses: Requires wall/countertop space; Fire TV integration can feel secondary; no Z-Wave/Zigbee hub; privacy concerns with always-on display.
Bottom Line: The ultimate family hub for kitchens or common areas, excelling in organization and entertainment. Ideal for households wanting a central information and media station, though its size and focus make it less suited as a primary smart home controller than dedicated hubs.
4. Amazon Echo Spot (newest model), Great for nightstands, offices and kitchens, Smart alarm clock, Designed for Alexa+, Black
Overview: The Echo Spot is a compact smart alarm clock with a spherical display, designed for bedside, desk, or kitchen counter use. It combines essential clock functionality with Alexa voice control, vibrant sound, and smart home management, prioritizing simplicity and ambient utility in personal spaces.
What Makes It Stand Out: Its unique spherical screen and compact form factor make it ideal for tight spaces like nightstands. The focus on gentle wake-up routines (gradual light/music) and glanceable info (time, weather, reminders) differentiates it from larger displays. Rich audio quality for its size enables it to double as a capable smart speaker.
Value for Money: Positioned as a premium clock, it offers excellent value by merging multiple functions: high-quality alarm clock, smart speaker, ambient info display, and smart home controller. It’s more cost-effective than buying separate devices for these roles, though basic smart speakers are cheaper if a display isn’t needed.
Strengths and Weaknesses: Strengths: Compact, space-saving design; vibrant sound quality; customizable clock faces; ideal for gentle wake-ups; intuitive touch controls; strong nightstand utility. Weaknesses: Small screen limits readability for complex tasks; no video calling; limited smart home dashboard depth; requires charging cable.
Bottom Line: A near-perfect smart alarm clock for bedrooms or small spaces, delivering exceptional audio and essential smart features in a compact package. Highly recommended for those seeking an Alexa-enabled bedside companion, though less versatile than larger displays for media.
5. Amazon Echo Show 11 (newest model), Vibrant Full-HD 11" display with more viewing area and spatial audio, Designed for Alexa+, Graphite
Overview: The Echo Show 11 bridges the gap between compact smart displays and large tablets, offering an 11" Full HD screen with significantly more viewing area than its 8" predecessor. It targets users wanting immersive media, clear smart home management, and natural video calls in living rooms or bedrooms.
What Makes It Stand Out: The 60% larger screen versus the Echo Show 8 (2025) and spatial audio provide a notably enhanced media experience. Omnisense technology enables advanced presence detection for personalized routines (e.g., adjusting thermostat when you enter), while the centered auto-framing camera revolutionizes video calls with 3.3x zoom and noise reduction.
Value for Money: It delivers compelling value as a versatile all-rounder: the size upgrade justifies the price over smaller models for media/viewing, and built-in hub functionality eliminates the need for separate hubs. Spatial audio and Omnisense tech add premium touches, though the lack of built-in Z-Wave remains a limitation versus dedicated hubs.
Strengths and Weaknesses: Strengths: Large, vibrant 11" display; excellent spatial audio; advanced Omnisense presence detection; superb video calling; built-in smart home hub; ideal for recipes/calendars. Weaknesses: No Z-Wave/Zigbee support; larger footprint than Show 8; premium features require Alexa+ subscription; screen glare can be an issue.
Bottom Line: A top-tier smart display for immersive media, clear communication, and intuitive smart home control. Its size and audio advancements make it a standout for living spaces, highly recommended for Alexa users seeking a balanced, high-quality display experience.
6. Smart Home Starter Kit | Includes Echo Hub, Amazon Smart Plug and 4 Amazon Basics Smart Bulbs, Designed for Alexa+
Overview:
This all-in-one kit simplifies smart home entry, bundling Amazon’s Echo Hub, a Smart Plug, and four Basics Smart Bulbs. Designed exclusively for Alexa users, it targets beginners seeking effortless setup and core automation without technical complexity.
What Makes It Stand Out:
The guided, tap-to-start setup eliminates configuration headaches, while the Echo Hub unifies control of thousands of Alexa-compatible devices. The four bulbs enable “away mode” automation for security, and seamless integration with Ring cameras enhances home safety—all managed through a single, intuitive Alexa interface.
Value for Money:
Priced competitively against buying components separately, it delivers exceptional entry-level value. Though limited to Alexa ecosystems, the bundled hardware (worth $120+ standalone) justifies the cost for Amazon-centric households, avoiding piecemeal purchases.
Strengths and Weaknesses:
Strengths: Effortless installation; cohesive Alexa integration; practical security features via bulbs; strong compatibility with Amazon’s ecosystem.
Weaknesses: No support for Google/Apple ecosystems; bulbs lack color customization; Hub requires a separate Echo speaker for voice control.
Bottom Line:
Ideal for Alexa newcomers wanting a hassle-free start, this kit excels in simplicity and core functionality. While inflexible for multi-platform users, its seamless setup and bundled value make it a top-tier entry point for Amazon-focused smart homes.
7. Aqara Smart Home Hub M3 for Advanced Automation, Matter Controller, Thread Border Router, Features Zigbee, Bluetooth, Wi-Fi, PoE, IR, Supports Alexa, Apple HomeKit, SmartThings, Home Assistant, IFTTT
Overview:
Aqara’s M3 Hub is a powerhouse for advanced users, supporting Matter, Thread, Zigbee, and IR control. It bridges ecosystems like Home Assistant and Apple HomeKit while enabling local automation—prioritizing speed, privacy, and expansive device compatibility beyond basic hubs.
What Makes It Stand Out:
Its Edge computing shifts automations offline for reliability, even during internet outages. The smart IR blaster learns and confirms device states (e.g., AC status), while Matter bridging syncs Aqara-exclusive scenes. PoE, dual-band Wi-Fi, and encrypted local storage cement its pro-grade appeal.
Value for Money:
At a premium price, it’s justified for enthusiasts needing local processing and multi-protocol support. Cheaper hubs lack its Matter/Thread depth or IR feedback, making the M3 a cost-effective long-term investment for complex, privacy-focused setups.
Strengths and Weaknesses:
Strengths: Robust local automation; Matter/Thread leadership; IR blaster with status feedback; enterprise-grade security; versatile wired/wireless options.
Weaknesses: Steep learning curve; 127-device limits per protocol; requires router proximity; no microphone/camera reduces utility for voice-centric users.
Bottom Line:
A must for tech-savvy users building a future-proof, multi-ecosystem home. Despite its complexity, the M3’s local processing, Matter integration, and IR intelligence offer unmatched flexibility for serious smart home architects.
8. Tapo Smart IR & IoT Hub with Chime - Universal Remote for TVs, ACS, & 18+ Device Types, Matter-Certified, Supports 8,000+ Infrared Brands, Voice & App Control, Custom Schedules & Automations, H110
Overview:
TP-Link’s Tapo H110 Hub merges IR universal remote functionality with basic smart home control. It manages 8,000+ IR devices (ACs, TVs) and Matter-compatible smart gadgets via app or voice, positioning itself as an accessible bridge for legacy electronics.
What Makes It Stand Out:
Its universal IR database covers virtually all major brands, while Matter certification ensures cross-platform voice control (Alexa/Google/Siri). The built-in chime provides instant alerts, and CISA-backed cybersecurity pledges address privacy concerns rare in budget hubs.
Value for Money:
Priced below $50, it outperforms single-protocol hubs for IR-heavy households. While lacking advanced automation, consolidating control of legacy devices and new Matter gadgets at this price offers compelling value for casual users.
Strengths and Weaknesses:
Strengths: Exceptional IR compatibility; Matter-certified for broad voice assistant support; strong security focus; intuitive Tapo app; ideal for IR device integration.
Weaknesses: Limited to 15 automations; no Thread/Zigbee; weaker local processing than premium hubs; chime can’t replace dedicated security systems.
Bottom Line:
Perfect for simplifying control of existing IR appliances alongside new smart devices. Its security focus and Matter support make it a standout budget choice, though power users will need supplementary hubs for complex automations.
9. Amazon Echo Show 5 (newest model), Smart display, Designed for Alexa+, 2x the bass and clearer sound, Glacier White
Overview:
Amazon’s compact Echo Show 5 packs a 5.5” display, upgraded audio, and Alexa into a bedside or desk-friendly device. It focuses on visual interactions—video calls, media streaming, and smart home control—without the bulk of larger displays.
What Makes It Stand Out:
Doubled bass and clearer vocals elevate audio for music/podcasts, while the screen enables glanceable info (weather, calendars) and photo slideshows. Tight integration with Alexa lets users view doorbell feeds, control thermostats, and make drop-in calls effortlessly.
Value for Money:
At $60, it’s Amazon’s most affordable display. The audio upgrade justifies the slight price bump over older models, offering better sound than competitors like the Nest Hub Mini. However, it lacks the smarts of pricier hubs (e.g., no Zigbee).
Strengths and Weaknesses:
Strengths: Richer sound quality; compact size; seamless Alexa/video calling; unlimited Prime photo storage; ideal as a secondary room display.
Weaknesses: Screen resolution feels dated; camera quality is mediocre; requires other hubs for full smart home control; privacy concerns with always-on mic/camera.
Bottom Line:
A superb entry-level display for Alexa enthusiasts prioritizing sound and convenience. While not a standalone hub, its audio upgrades and compact design make it a worthwhile upgrade for casual users seeking hands-free smart home interactions.
Understanding the Core Role of a Smart Home Hub
Why a Dedicated Hub Beats Relying Solely on Your Phone
Relying only on your smartphone for smart home control creates fragility. If your phone dies, loses internet, or simply isn’t nearby, your entire system can become unresponsive. A dedicated hub operates independently on your home network, ensuring lights turn on, locks secure, and sensors trigger automations even when your phone is off or out of the house. It acts as the central nervous system, constantly communicating with devices using specialized low-power protocols your phone often can’t handle directly.
Bridging the Communication Gap Between Devices
Smart home gadgets speak many different “languages” (protocols like Wi-Fi, Bluetooth, Zigbee, Thread). A hub’s primary job is translation. It connects to your home Wi-Fi router and then uses built-in radios (like Zigbee or Thread) to talk directly to compatible devices. This creates a more reliable, responsive, and energy-efficient mesh network than if every device tried to connect directly to your distant Wi-Fi router, reducing network congestion and device battery drain.
Essential Features for Starter Budget Hubs
Non-Negotiable Protocol Support
For true value and longevity, prioritize hubs supporting at least two major low-power mesh protocols. Zigbee remains incredibly widespread for sensors, bulbs, and plugs, offering excellent range and device compatibility. Thread, especially when combined with the Matter standard, is rapidly growing for future-proofing and ultra-reliable, low-latency connections. Avoid hubs limited only to Bluetooth or proprietary systems, as they severely restrict your device choices and scalability.
Matter and Thread Readiness: Your Future-Proofing Lifeline
Matter is the game-changer, an open standard designed to ensure devices from different brands work together seamlessly over Thread or Wi-Fi. While full Matter-over-Thread adoption is still evolving in 2026, a hub with built-in Thread border router capability is crucial. It allows Matter devices to connect directly and form a resilient mesh, significantly improving reliability and simplifying setup. Ensure the hub explicitly states it functions as a Thread border router for Matter.
Voice Assistant Integration Choices
Decide early: which voice assistant aligns with your habits? Most budget hubs integrate tightly with either Amazon Alexa or Google Assistant (built-in microphones/speakers are rare at this price point; they usually connect to your existing Echo or Nest device). Verify the hub’s compatibility with your preferred assistant before purchase. Seamless voice control for routines and device management is a cornerstone of the smart home experience.
Evaluating Performance and Reliability
Local Processing vs. Cloud Dependence
This is critical for responsiveness and resilience. Hubs relying entirely on the cloud for automations (like “turn on lights when motion detected”) become useless during internet outages. Prioritize hubs advertising “local control” or “on-hub processing” for core automations. This means simple rules execute directly on the hub via your home network, keeping essential functions running even when the internet is down. Cloud reliance is generally acceptable for complex routines involving external triggers.
Network Stability and Range Considerations
The hub’s physical placement matters. It needs a central location, preferably elevated and away from large metal objects or thick walls, to maximize its radio range for Zigbee/Thread devices. Check user experiences (not just specs) regarding real-world range performance with low-power devices. A hub with a strong, stable radio ensures sensors and devices throughout your starter space (like a single floor or apartment) connect reliably without frequent dropouts.
Firmware Update Commitment
Smart home tech evolves rapidly. A hub manufacturer’s commitment to regular, long-term firmware updates is non-negotiable. These updates fix security flaws, improve performance, add new compatible devices, and sometimes introduce new features. Research how long the company typically supports older models and how seamless their update process is. A hub abandoned after 12 months becomes a security risk and loses functionality.
Setup, Usability, and the User Experience
App Simplicity and Intuitiveness
Your hub’s companion app is your control center. For beginners, a clean, logical interface is paramount. Look for apps known for straightforward device pairing, clear automation creation (often called “scenes” or “routines”), and easy navigation. Complicated, cluttered apps create frustration and abandonment. Check reviews specifically mentioning the app experience for new users—avoid hubs where setup requires technical jargon or complex network configuration.
Automation Engine Capabilities
The power of a hub lies in automations. Even budget hubs should allow basic “if this, then that” rules: “If motion detected after sunset, turn on hallway light for 5 minutes.” Evaluate the flexibility: Can you trigger actions based on multiple conditions (time, sensor state, presence)? Can you set delays or execute multiple actions? Avoid hubs with extremely limited or rigid automation options, as they hinder creating truly useful scenarios.
Onboarding Process for New Devices
Adding new smart devices should be painless. The best hubs support standard pairing methods like “touchlink” for Zigbee (pressing a button on the device) or QR code scanning for Matter. Avoid hubs requiring obscure manual entry of network keys or complex reset sequences for every new bulb or sensor. A smooth onboarding experience encourages expanding your setup.
Security: The Non-Negotiable Foundation
Built-in Security Protocols
Security isn’t optional. Ensure the hub implements robust encryption (like AES-128 or better) for communication between the hub, your devices, and the cloud. It should support secure boot to prevent tampering and have mechanisms to isolate compromised devices. Research if the manufacturer follows security best practices like regular penetration testing and has a clear vulnerability disclosure process.
Privacy Controls and Data Handling
Understand what data the hub collects and how it’s used. Does the companion app allow granular control over data sharing? Can you disable cloud features you don’t use? Reputable manufacturers provide clear privacy policies. Avoid hubs with vague policies or a history of questionable data practices. Your home network security starts with the hub.
Physical and Network Security Practices
Beyond the hub itself, secure your home Wi-Fi network (strong password, WPA3 encryption). Place the hub on a separate IoT network/VLAN if your router supports it, isolating smart devices from your main computers and phones. Regularly update the hub’s firmware the moment updates are available—this is often the easiest way attackers gain access.
Maximizing Your $100 Starter Investment
Defining Your “Starter Setup” Scope
Be realistic. A $100 hub budget means focusing on core functionality for a limited area (e.g., living room + entryway). Prioritize hubs that excel at connecting the foundational devices you plan to buy first: smart plugs, a few bulbs, a motion sensor, and maybe a door lock. Don’t pay for multi-room audio support or advanced security integrations you won’t use immediately.
Avoiding the “Cheap Trap”
The absolute cheapest hub often lacks critical features like Thread, local processing, or robust security. It might use outdated protocols with limited future device support. Spending $10-$20 more within your budget can secure essential capabilities that prevent needing a replacement hub within a year, saving money long-term. Value trumps the lowest possible price.
Planning for Gradual Expansion
Choose a hub whose ecosystem naturally supports the devices you might want later (like smart blinds or advanced sensors). Check compatibility lists for brands you’re interested in. A hub with strong community support and frequent new device certifications offers the smoothest path from starter setup to a more comprehensive home. Ensure it has enough protocol capacity for your projected growth (e.g., 20-30 devices).
Getting Started: Your First Steps
Assessing Your Home Network Health
A weak or congested Wi-Fi network cripples any smart home. Before buying a hub, test your router’s coverage in key areas (like where you’ll place the hub and planned devices). Consider a simple Wi-Fi extender if needed. Ensure your router supports the 2.4 GHz band (essential for most low-power devices) and has a strong, unique password. A solid network is the invisible foundation.
Starting Small with Core Automations
Don’t try to automate everything day one. Begin with one or two highly useful, reliable automations: “Good Morning” (lights on gradually, thermostat adjusts) or “Away Mode” (lights off, locks engage, thermostat sets back). This builds confidence in the system’s reliability. Focus on automations using local triggers (like a physical switch or motion sensor) first for maximum uptime.
Leveraging Community Knowledge
Active user communities (forums, subreddits) are invaluable resources for troubleshooting, discovering hidden features, and learning best practices specific to your hub model. Search for the hub’s name plus “community” or “forum” before purchasing. A hub with a large, helpful user base significantly extends its usability and lifespan, especially for beginners.
Frequently Asked Questions
Frequently Asked Questions
Can I really build a smart home under $100 including the hub? Yes, absolutely. Focus the $100 budget specifically on the hub itself. Starter devices (like a smart plug or bulb) can often be found for $10-$15 each, allowing you to build a small, functional setup affordably.
Is a hub necessary if I only have a few Wi-Fi devices? For a very small setup (1-2 devices), you might manage via smartphone apps. However, a hub adds significant value immediately: enabling automations between devices, providing remote access without complex port forwarding, improving reliability, and laying the groundwork for adding non-Wi-Fi devices (sensors, locks) later.
Do all smart home hubs require a subscription? No, the vast majority of core hub functionality (local control, basic automations, device management) operates without any ongoing subscription fee. Some offer optional paid services for advanced features like professional monitoring or extended cloud storage for cameras, but these are not required for fundamental smart home operation.
How important is Wi-Fi 6 support for a budget hub? Wi-Fi 6 support on the hub itself is generally not critical for starter setups in 2026. The hub primarily uses its dedicated radios (Zigbee/Thread) to talk to devices. As long as the hub connects reliably to your existing 2.4 GHz Wi-Fi network (which most homes still have), its internal Wi-Fi standard is less important than its low-power protocol capabilities.
Can a budget hub support voice control without an extra device? Typically, no. Budget hubs under $100 rarely include built-in microphones and speakers. They integrate with your existing voice assistant device (like an Amazon Echo Dot or Google Nest Mini), which you’d need to purchase separately for voice control. The hub enables the voice assistant to control your connected devices.
What’s the biggest mistake beginners make with their first hub? Buying based solely on the lowest price without checking protocol support (especially Zigbee/Thread) and local automation capabilities. This often leads to compatibility dead ends, poor reliability, and needing to replace the hub within a year as the system expands, costing more in the long run.
How do I know if a hub will work with my existing smart devices? Check the manufacturer’s official compatibility list before purchasing the hub. Look for the specific models of your devices (e.g., “Brand X Smart Bulb Model YZ-100”). Don’t rely solely on protocol names (e.g., “Zigbee”) as implementation can vary; official lists are the only guarantee.
Will my hub become obsolete quickly? Hubs supporting Matter over Thread have the longest expected lifespan due to the open standard. Prioritize these. Hubs relying solely on older, proprietary systems or lacking Thread are at higher risk of becoming obsolete as the industry shifts towards Matter. Firmware update commitment is also key to longevity.
Can I use multiple hubs in one home? Yes, but it’s usually unnecessary for starter setups and can complicate management. Most single hubs can handle 20-50+ devices. If you have a very large home, ensure any additional hubs are from the same ecosystem and support mesh networking for seamless coverage, or use hubs that explicitly work together (like multiple Thread border routers in a Matter system).
What happens to my smart home if the hub loses power? Devices connected via Wi-Fi (like some plugs or cameras) will likely remain controllable via the internet/app if your router is on a UPS. However, low-power devices (Zigbee/Thread sensors, bulbs) connected through the hub will become unresponsive until the hub regains power and reconnects. Core automations relying on the hub will pause. A UPS for the hub/router is ideal for critical functions.