The best heater for a greenhouse will vary unit-to-unit as to climate, cost, and how well the greenhouse is built.
In my opinion, a gas or electric heater is the best to use, but for another, a wood burner may be a better option.
I live in the desert with no ready supply of wood, plus I don’t like the idea of waking up at 1:00 AM to add more wood to a stove.
One thing I would very much recommend is having a fan in combination with a heater to move the heat about.
What works for one person may not work for another so lets look at some popular options for heating greenhouses.
There are many units available with our favorite picks below.
As always be sure to read reviews on Amazon, here, or elsewhere to be sure a unit is the right pick for you.
*This post contains affiliate links.
Our Picks for Best Heaters for a Greenhouse
- Flat Panel Heater
- Oil Filled Radiator Heater
- Dr. Heater DR218-1500W
- Mr. Heater Buddy
- Propane Tank Top Heater Propane Heater
Cozy Products CL Safe Chicken Coop Heater 200 Watts Safer Than Brooder Lamps, One Size, Black
Flat-panel heaters are some very good units when set up correctly.
They can be hung on a wall up out of the way or set on small rollers.
The units don’t put out a large amount of heat but radiate a steady warmth that is ideal for plants.
Flat-panel heaters are nice to use in a greenhouse with a nice flow of heat.
Space heater, Aikoper 1500W Oil Filled Radiator Heater with 3 Heat Settings, Adjustable Thermostat, Quiet Portable Heater with Tip-over & Overheating Functions for Home, Office, Black
Oil-filled radiator heaters are another good option for heating a greenhouse.
They dont put out large amounts of heat but a steady flow that helps maintain a temperature.
They also cost less to use and are often used in combination with other heat sources.
They are very good units that can be set with a thermostat and help regulate the temperature in a greenhouse nicely.
Dr. Heater DR218-1500W Greenhouse Garage Workshop Infrared Heater, 1500-watt
The Dr. Heater DR218 is an electric unit with a fan and thermostat control to keep plants in a climate controlled environment.
It comes in two sizes, the standard 120 Volts unit, and the larger 220 Volt unit.
It has a waterproof rating of IPX4 which is rated to withstand splashes.
Mr. Heater F232017 MH9BXRV Buddy Grey Indoor-Safe Portable RV Radiant Heater (4,000-9,000-BTU)
Mr Buddy is a very popular gas heater that works very well keeping a space warm.
It has a lot of nice features such as tip-over protection which shuts the unit off in an emergency.
The gas bottles are not large like other gas units but its popularity makes it a top pick.
COSTWAY 15,000 BTU Propane Tank Top Heater, Portable Infrared Heater with Safety Shut-off Valve and Tip-over Switch, CSA Certification for Outdoor, Camping, Deluxe (Propane Cylinder not Included)
Propane gas heaters are also popular since they are cheap to run and can put out a lot of heat.
The problem with any gas unit is there must be some ventilation as they put out a lot of CO2 which can be dangerous to people.
For example, they are often used in garages with the door open for heat.
Be sure to read the warnings and instructions before using such a unit.
Since heating a greenhouse in the winter can be the biggest expense often using a combination of heating units is the best option.
Having a thermostat is a must for leaving a unit operating overnight along with other features such as tip-over-shut-off protection.
Having fans that circulate the air is also important.
A wood-burning stove is a good option if you have a ready source of wood to burn. Keep in mind how much work will be involved though in cutting, splittings, stacking and so on.
Electric units are also very good but be sure to have a dedicated outlet to run them. Using an extension cord is not a good idea and should never be done with an electric heater.
Gas-powered units can out put a lot of heat and when set up correctly works very well. Since they put out so much heat it is best to keep them pointed away from any plants.
How well a greenhouse is built and how high the roof is can also have an impact. Since heat rises a high roof will hold the heat higher up.
Whichever unit is chosen be sure to be safe and follow the instructions that come with your heating unit.