AC Infinity SUNCORE H3 heat mat
The SUNCORE H3 keeps the 10-by-20.75-inch footprint and adds a digital temperature display with an adjustable setting.
Read our take
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Seedling Heat MatsOUR TAKE
AC Infinity SUNCORE S3 heat mat
A 10-by-20.75-inch seedling heat mat with variable heat control.
The S3 belongs under a planned propagation tray when adjustable heat output is useful in the seed-starting corner.
- Good for
- A suitable indoor germination setup needing a mat-sized warming surface.
- Look elsewhere if
- The setup needs measured setpoint thermostat control rather than a variable-output dial.
- The tradeoff
- Adjusting output is different from choosing a measured soil-temperature setpoint.
At a glance
- Mat size
- 10 x 20.75 inches
- Control
- Variable-output heat dial
- Power
- 20W; 100–125V AC
Why it earns a look
- 10 x 20.75 inches.
- Variable-output heat dial.
Where it asks for a compromise
- Adjusting output is different from choosing a measured soil-temperature setpoint.
Make a useful propagation corner
The S3 belongs under a planned propagation tray when adjustable heat output is useful in the seed-starting corner. Plan the tray, watering access, and the equipment around it as a complete arrangement before filling the shelf with seedlings.
Living with it in the garden
Use the settings and placement allowed by the instructions.
Keep the electrical connections appropriately arranged around watering.
Which one belongs in your shed?
AC Infinity 72-cell light-and-mat dome kit
The 72-cell dome kit includes a heating mat, LED bars and trays when you need a complete seed-starting arrangement rather than a separate mat.
Read our takeYour SUNCORE S3 questions
What is included in the basic arrangement?
10 x 20.75 inches with variable-output heat dial.
Does the setting replace plant-specific care?
Choose the setting and placement for the crop and stage of growth, following the equipment instructions.
Full specifications, manuals & sources
Model details
- Full model name
- AC Infinity SUNCORE S3, Seedling Mat 10" x 20.75" w/ Variable Heat Control
- Amazon ASIN
- B09TNGKDPJ
- Power source
- Corded electric
- Growing use
- Seed starting
- Brand
- AC Infinity
Manuals & product information
Photo sources
Product information checked 2026-10-29. Our assessment uses the linked specifications and manuals; it does not represent a hands-on test. Editorial standards & corrections.