Best Electric Heaters for Small Greenhouses

Maintaining the ideal temperature in a small greenhouse is essential for fostering healthy plant growth, especially during chilly seasons or unexpected cold snaps. While natural sunlight provides warmth during the day, nighttime and overcast days often require supplemental heating to protect sensitive plants from cold stress. Electric heaters are a popular choice for greenhouse heating due to their efficiency, ease of use, and safety features. This article explores the best electric heaters tailored specifically for small greenhouses, highlighting what to look for when choosing one and reviewing top models on the market.

Why Use Electric Heaters in Small Greenhouses?

Small greenhouses have limited space and typically serve hobbyists or small-scale gardeners. The unique environment inside a greenhouse requires a heating solution that is:

Compact: Space inside a small greenhouse is limited.
Efficient: The heater should provide consistent warmth without excessive energy consumption.
Safe: Given the presence of plants and sometimes moisture, heaters must have safety features to prevent accidents.
Affordable: Hobbyists often seek budget-friendly options without compromising performance.

Electric heaters excel in these areas because they are easy to install (usually just requiring an electrical outlet), offer adjustable heat settings, and come with safety certifications like overheat protection and tip-over switches.

Key Features to Consider When Choosing an Electric Heater for a Small Greenhouse

Before diving into specific models, it’s crucial to understand what features matter most for greenhouse heating purposes.

1. Heater Type

There are several types of electric heaters available, including:

Fan-forced heaters: These use a fan to blow warm air across fins or coils. They heat areas quickly but may cause uneven heat distribution if not positioned well. They can also cause air movement that might stress delicate plants.
Oil-filled radiators: These heaters warm oil inside sealed fins which then radiate heat evenly. They operate silently and provide steady warmth even after being turned off but take longer to heat up.
Ceramic heaters: Utilize ceramic plates that heat up quickly with fan assistance; they are efficient and compact.

For a small greenhouse, oil-filled radiators or ceramic heaters are often favored due to their gentle, consistent heat output that doesn’t overly dry out the air.

2. Size and Portability

Small greenhouses need compact heaters that can fit onto shelves or corners without taking up too much space. Portability allows you to move the heater as needed based on plant placement or season.

3. Power Output (Wattage)

Heater wattage determines how much heat it can produce. A general rule of thumb is that you need about 10 watts per square foot of space in a well-insulated greenhouse.

For example:

A 50 sq ft greenhouse needs approximately 500 watts.
A 100 sq ft greenhouse needs approximately 1000 watts.

Check your greenhouse size and select a heater with appropriate wattage to maintain desired temperatures efficiently.

4. Thermostat Control

A built-in thermostat helps maintain consistent temperature by automatically cycling the heater on or off based on ambient conditions. This prevents overheating and conserves electricity.

5. Safety Features

Given the humid environment in greenhouses and presence of water, safety is paramount:

Overheat protection: Shuts off heater if it gets too hot.
Tip-over switch: Turns off heater if knocked over.
Water resistance or splash-proof design: Important if your heater will be exposed to moisture.

6. Noise Level

Some electric heaters use fans which can create noise. Silent operation is preferable in greenhouses where peaceful conditions promote better plant health.

Top Electric Heaters for Small Greenhouses in 2024

Based on these considerations, here are some of the best electric heaters suitable for small greenhouses:

1. DeLonghi Oil-Filled Radiator Heater (EW7707CM)

The DeLonghi EW7707CM is an excellent oil-filled radiator heater ideal for small greenhouse spaces up to 150 sq ft.

Wattage: 1500W
Features:
Adjustable thermostat for precise temperature control.
Silent operation with no fan noise.
Overheat protection and anti-freeze setting.
Compact design with caster wheels for portability.

Why it’s great: The slow-release radiant heat mimics natural warmth, preventing rapid temperature swings that might shock plants. Its silent operation ensures no disturbance within your gardening environment.

2. Lasko Ceramic Portable Space Heater (Model 755320)

This ceramic heater offers quick heating suitable for very small greenhouses or propagation boxes.

Wattage: 1500W (high), 900W (low)
Features:
Adjustable thermostat with two power settings.
Overheat protection and cool-touch housing.
Compact size easy to place on shelves or benches.

Why it’s great: The rapid heating capability helps during sudden cold drops, while its safety features make it reliable around sensitive plants.

3. Vornado VH202 Personal Space Heater

Vornado’s compact heater uses vortex air circulation technology providing even heat distribution in tight spaces.

Wattage: Variable up to 1000W
Features:
Thermostatic control.
Tip-over protection and automatic safety shutoff.
Cool-touch exterior.

Why it’s great: Efficiently warms small areas with minimal noise and energy consumption—perfect if your greenhouse space is under 100 sq ft.

4. Dr Infrared Heater Portable Space Heater (Model DR968)

Known for durability and effectiveness in various environments, this infrared heater is suited for maintaining steady temperatures in greenhouses.

Wattage: Up to 1500W
Features:
Dual heating system combining infrared and convection heat.
Digital thermostat with timer function.
Overheat protection and tip-over switch.

Why it’s great: Infrared heat warms objects directly rather than just air, which can be beneficial in greenhouses where soil and plants retain warmth longer than air alone.

5. Honeywell HCE200W UberHeat Ceramic Heater

This ultra-portable ceramic heater is compact enough for mini-greenhouses or propagation stations inside larger structures.

Wattage: Up to 1500W
Features:
Adjustable thermostat with multiple heat settings.
Safety features include tip-over switch and overheat protection.
Cool-touch housing ideal around delicate plants.

Why it’s great: Its size makes it extremely versatile, offering supplemental warmth exactly where needed without taking up much space.

Tips for Using Electric Heaters Safely in Your Greenhouse

To maximize benefits while keeping your plants safe, keep the following tips in mind:

Positioning: Place heaters away from direct contact with plants but close enough to warm ambient air effectively. Avoid placing them near water sources or irrigation systems.
Ventilation: Ensure some airflow so heat circulates evenly but avoid drafts that cause rapid temperature fluctuations.
Temperature Monitoring: Use an external thermometer/hygrometer combo to monitor humidity along with temperature since heaters can dry out air which may harm certain plants.
Timer Usage: Consider using timers or smart plugs so heaters don’t run continuously but cycle as needed during cold periods or overnight only.

Conclusion

Selecting the right electric heater for your small greenhouse can significantly influence plant health during colder months by providing consistent, safe warmth without taking up precious space. Whether you choose an oil-filled radiator for gentle steady heat, a ceramic fan heater for quick warming, or an infrared model for direct plant warming, prioritize features like accurate thermostats, safety mechanisms, appropriate wattage, and portability.

Among top recommendations are the DeLonghi EW7707CM oil-filled radiator for quiet all-night use, the Lasko Ceramic Heater for quick bursts of warmth, and Vornado’s compact model for efficient circulation in tight spaces. By investing thoughtfully in your heating setup—and practicing safe usage—you can extend your growing season year-round and enjoy thriving plants regardless of outdoor chill.