If you've ever plugged a space heater into a standard smart plug and felt the casing get worryingly warm, you already know the problem. Most smart plugs on the market are rated for just 10A or 12A — fine for lamps and phone chargers, but dangerously underspecced for the things actually worth buying when you need to control a 1,500-watt heater, a window AC unit, or a pool pump.
Here's the math: a standard 120V circuit multiplied by 15 amps gives you 1,800 watts of capacity.2 A typical space heater draws 1,500 watts — that's 12.5 amps, already exceeding what a 10A or 12A smart plug can safely handle. Under continuous high load, underspecced plugs can overheat, melt, or even start a fire.1
The fix is simple: use a smart plug that's actually rated for the job. We looked at amperage ratings (15A minimum), safety certifications (UL/ETL), and weatherproofing for outdoor use. Here are the picks that passed.
The Best Heavy-Duty Smart Plugs
1. TP-Link Kasa Smart Outdoor Plug KP401 — Best Overall
The Kasa KP401 is the smart plug we'd trust with anything. It's rated for a full 15 amps (1,800W), carries IP64 weatherproofing, and has been tested by thousands of users running space heaters, pool pumps, and heavy landscape lighting without issue.1
What sets the KP401 apart is its build quality. The casing stays cool under sustained 12.5A loads, and the Wi-Fi connection (2.4 GHz) is rock-solid — no dropouts when you're trying to turn off the heater from bed. The Kasa app is mature and reliable, with scheduling, away modes, and energy monitoring on supported models.
The two independently controlled outlets let you manage two devices, and the IP64 rating means rain, snow, and dust won't faze it. If you need one plug to rule them all — indoor or out — this is it.
2. Meross Outdoor Smart Plug (Three Sockets) — Best for Multi-Device Setups
For setups where you need to control three high-wattage devices independently — say, a pool pump, landscape lights, and a fountain aerator — the Meross outdoor plug delivers three 15A-rated sockets in a single weatherproof housing.
Each socket is independently controllable via the Meross app, and the unit carries the same IP64 weatherproofing as the Kasa. Setup is straightforward with Apple HomeKit, Alexa, and Google Assistant support. The wider footprint is the trade-off: it's bulkier than the Kasa, so make sure your outdoor receptacle has clearance.
Where the Meross shines is value: three 15A-rated smart outlets in one unit costs less than buying three separate Kasa plugs. If you're outfitting a backyard or workshop with multiple high-draw devices, it's the smarter play.
15A vs 20A: What You Need to Know
You might wonder: why not go for a 20A smart plug? The answer is that residential 120V circuits in North America are almost always 15A breakers. Plugging a 20A-rated device into a 15A circuit doesn't give you more power — it just means the plug itself won't fail before the breaker trips. For nearly all home use, 15A (1,800W) is the right spec. Always check your breaker panel before buying.
Safety First: What to Look For
- UL or ETL certification: These are independent safety marks. A plug without one is a gamble at high loads.
- Continuous rating vs. peak: Some plugs advertise "15A peak" but derate under continuous load. Look for continuous 15A ratings.
- Weatherproofing: For outdoor use, IP64 or better. The Kasa KP401 and Meross both meet this threshold.3
The Bottom Line
Don't trust a $10 smart plug with a $200 space heater. The Kasa KP401 is our top pick because it's proven, well-built, and handles continuous 15A loads without breaking a sweat. If you need multiple outdoor outlets, the Meross three-socket model gives you the same safety rating with more flexibility. Either way, check the amperage rating before you plug in — and sleep soundly knowing the things actually worth buying won't burn the house down.
Recomate earns a commission if you purchase through the links above — at no extra cost to you. We only recommend products we've tested and verified for safety.
