A greenhouse heater makes it possible to create suitable plant and vegetable growing temperatures year-round. Greenhouses are used by hobby gardeners for several reasons: to optimize growing conditions, extend a plant’s growing season, or create a microclimate for year-round cultivation. But when the mercury drops, a greenhouse might need a little extra help to maintain a suitable temperature. A good greenhouse heater does just that, warming up the air in the greenhouse and maintaining the temperature safely, reliably, and sustainably. Read on for the best greenhouse heater options to keep greenhouse plants happy and thriving.
- BEST OVERALL: Bio Green Palma Greenhouse Fan Heater
- BEST BANG FOR THE BUCK: Dr. Infrared Heater DR-218 Greenhouse Workshop Heater
- BEST GAS HEATER: Mr. Heater Little Buddy Heater
- BEST SOLAR KIT: Renogy 200 Watt 12 Volt Solar Starter Kit
- BEST CEILING-MOUNTED: Comfort Zone 5000-Watt Fan-Forced Industrial Heater
- BEST FOR SMALL GREENHOUSES: Vornado TAVH10 Whole Room Heater with Auto Climate
- BEST FOR LARGE GREENHOUSES: Dr. Infrared Heater DR-975 7500-Watt Electric Heater
Types of Greenhouse Heaters
In some areas, the sun alone can adequately heat a greenhouse, but colder areas may call for additional artificial heat to support plant growth. Greenhouse heaters do so using a few different methods depending on the type of device. Broadly speaking, most greenhouse heaters can be categorized into the following types: electric, gas, solar, and paraffin.
Electric heaters are efficient, easy to set up, and simple to maintain. Getting started with many electric heaters is as straightforward as plugging them into an outlet and switching them on. Since these heaters are also affordable, safe, and portable, they’re amongst the most popular options for many hobby gardeners. They can also come with additional features like built-in thermostats and timers. Electric heaters don’t emit any harmful fumes, so they can be used in greenhouses with minimal venting
One downside of electric heaters is that they require plugging into an outlet, which means the electrical system needs to reach the greenhouse. Water and humidity can also negatively affect electric heaters, so make sure the heater is suitable for using in greenhouse conditions. Many electric greenhouse heaters are splash-resistant to prevent water damage and electrocution.
Like gas patio heaters and other outdoor heaters, gas greenhouse heaters use natural gas or propane to create warmth, with propane being far more popular. While natural gas is less expensive than propane, fewer homes have the necessary natural gas pipeline running to the greenhouse, which is the main reason propane is more commonly used.
Propane gas heaters are hooked up to a propane tank, making them a great choice for greenhouses that lack an electricity source or a natural gas line. However, gardeners must replace the propane tanks frequently to maintain heat.
Regardless of the gas type, it’s crucial to ensure adequate venting so that the gas burns properly and doesn’t build up inside the greenhouse, which can be dangerous.
Those desiring a sustainable heating method that’s even easier to maintain than gas- or electric-powered units can consider installing a solar heating system. By pairing a solar panel kit with a heater, users can create a self-sufficient solar heater for greenhouse use that draws energy from the sun (much like the greenhouse itself). Solar systems don’t require connection to the electric system, natural gas line, or a gas source.
While there aren’t stand-alone solar greenhouse heaters on the market yet, this exciting new technology is worth considering for sustainability focused gardeners. Installing a solar system takes more work than just plugging in an electric heater, but a starter solar kit can provide the panels and wiring to get started. Just make sure to add a battery so the charge can be stored, allowing the system to operate when the sun isn’t out—the times when heating is most needed.
Paraffin greenhouse heaters are an old-school option for maintaining warmth. These basic heaters have a wick that, once lit, draws a liquid fuel from the holding tank beneath. Used by gardeners for many decades, these devices provide a low-cost and stable heat source that doesn’t require electricity or a gas line or tank.
However, since they must have a lit flame, they present a fire risk. Many of these heaters have a safety feature that extinguishes the flame if they are tipped over, but as is the case with any flame, they can still pose a hazard. Like gas heaters, paraffin heaters also release air pollutants, so they need adequate ventilation to be used safely. They’ll also need frequent monitoring to ensure the fuel source doesn’t run out. While paraffin heaters are still used by some gardeners, we have not included any in our lineup since safer and more user-friendly options are widely available.
What to Consider When Choosing the Best Greenhouse Heaters
In many climates, a greenhouse heater is necessary for cultivating plants year-round. The best heater for greenhouse settings helps to create a controlled environment for plant and vegetable growth. Besides the greenhouse heater type, there are a few important factors to look for when choosing the best greenhouse heater for your garden, including the heater’s heating capacity, temperature controls, and safety features.
When choosing a greenhouse heater, it’s very important to consider the ideal greenhouse temperature. The plant types inside will determine the best temperature; winter crops will thrive in a different climate compared to tropical plants, for example. Before choosing how powerful of a heater is needed, consider a few factors: the goal temperature, the local climate, and the size and construction of the greenhouse.
One common specification seen on greenhouse heaters is a BTU (British thermal unit) rating. One BTU refers to how much heat is needed to raise the temperature of a pound of water by one degree Fahrenheit. BTU is essentially a measure of energy output, so the BTU rating indicates how powerful the heater is.
When it comes to heating appliances, the BTU rating is measured in BTUs per hour. The higher the BTU rating, the more powerful the device. BTU calculators can be used to determine more accurately how many BTUs are needed to heat up a greenhouse (and good ones will consider the climate, intended temperature, and greenhouse materials). Some greenhouse heater manufacturers advertise the recommended coverage area of their heaters to give gardeners a more general sense of coverage.
The simplest of greenhouse heaters are turned on and off manually, which means users must frequently check the greenhouse temperature to prevent under- or overheating. More advanced heaters have built-in temperature controls with a thermostat that monitors the temperature and switches the heater on and off as needed.
Choosing a heater with or without temperature controls depends on personal preference. Some gardeners choose to go without if they can check the greenhouse frequently, if the heater is only used rarely, or if they are confident they can choose the right heater power for their greenhouse. However, a heater with built-in temperature controls is very convenient and offers great peace of mind, not to mention that a thermostat can also help conserve energy since it will only switch on the heater when necessary.
When heat isn’t properly circulated, this lowers heating efficiency and can even damage plants if certain areas get too warm. Greenhouse heaters with fans can help circulate the air around the room and prevent hot pockets of air.
Many greenhouse heaters include safety features to help prevent any mishaps. One feature to consider is an auto shutoff, which will turn off the heater if it gets too hot or accidentally tips over. This feature helps keep heaters from becoming a fire hazard.
Electric greenhouse heaters should ideally be water-resistant to lower the chance of damage or electrocution.
Automatic timers are a convenient feature, but they can also add to safety by giving gardeners the option to switch off the heater before risking the greenhouse overheating.
Some gas heaters include an oxygen depletion sensor that shuts off the heater when it senses the oxygen in the room is low. This possibly lifesaving safety feature ensures the heater shuts off before the oxygen is depleted in the room.
Our Top Picks
The best greenhouse heaters described ahead are user-friendly and reliable to help keep tasty fruits and vegetables and prized blooms alive in cold weather.
Designed specifically for greenhouses, the Bio Green Palma Greenhouse Fan Heater is the best greenhouse heater for a host of hobby gardeners. Stand-out features of this 1500-watt electric heater include its digital thermostat, sturdy stainless steel build, and compact floor-standing design. This heater is intended for spaces up to 120 square feet, making it suitable for most home greenhouses.
This convenient heater has an attached digital thermostat that can be mounted at eye level for easier use. The thermometer displays ambient temperature and has a control range of 0 to 90 degrees Fahrenheit to cover the needs of most gardeners. To use, simply set the desired room temperature and the heater will switch on when needed to warm the greenhouse. This model also features a ventilation fan to ensure against undesirable cold or hot air pockets.
A lightweight design and carry handle make the heater easily portable. For safety in a greenhouse setting, this model is IPX4 splash-proof and has an auto-shutoff feature in case of overheating.
- Type: Electric
- BTUs: 5,120 BTUs
- Coverage area: 120 square feet
- Easy to set up and use
- Robust digital thermostat
- Excellent air circulation
- Relatively short 6-foot power cord
Get the Bio Green greenhouse heater at Amazon, The Home Depot, Target, Wayfair, or Bio Green.
Gardeners on a budget will appreciate the Dr. Infrared Heater DR-218 Greenhouse Workshop Heater, which offers heating for up to 150 square feet for an affordable price. This 1500-watt electric heater is simple to use, with just enough settings to help keep tender plants warm.
Users can choose a heat or fan-only mode and turn the temperature dial to set the heat. The heating mode uses fan-forced air technology to encourage air circulation. While the thermostat dial doesn’t display the greenhouse’s ambient temperature, it can be set to maintain a set point temperature.
Although cost-friendly, this unit doesn’t skimp on its safety features. It’s designed to stay cool to the touch, has an IPX4 splash-proof build, and features an automatic shutoff if the unit overheats, making it extra safe for greenhouse use.
- Type: Electric
- BTUs: 5,200 BTUs
- Coverage area: 150 square feet
- Simple to use
- Good safety features
- Does not display ambient temperature
Get the Dr. Infrared Heater DR-218 greenhouse heater at Amazon, The Home Depot, Wayfair, or Dr. Infrared Heater.
For gardeners without an electric line to the greenhouse, a gas heater is a convenient solution. The Mr. Heater Little Buddy Heater is an indoor-safe propane model ideal for small greenhouses up to 95 square feet.
This compact portable heater is powerful for its size. All it needs is a 1-pound propane cylinder and a click-and-hold touch of the one-button ignition to start heating. A 5.6-hour runtime suits this heater best for light-duty use. Its upright design gives it a small footprint, perfect for placing in the corner of a small greenhouse. Lightweight and boasting a built-in handle, it’s easy to move around.
An Oxygen Depletion Sensor and automatic shutoff make this heater safe for indoor use. The heater constantly monitors the oxygen level in the room, shutting off if it gets too low. In case the unit is accidentally tipped over, it will automatically switch off.
- Type: Gas (propane)
- BTUs: 3,800 BTUs
- Coverage area: 95 square feet
- Easy to use
- Oxygen depletion and accidental tip-over safety shutoff
- Only suitable for small greenhouses
- Narrow base makes it easier to tip over
Get the Mr. Heater greenhouse heater at Amazon, The Home Depot, Tractor Supply Co., or Mr. Heater.
Solar power offers an eco-friendly alternative to electric and gas heaters. For gardeners keen on sustainability, setting up solar panels is the first step to creating a solar greenhouse heating system. The Renogy 200 Watt 12 Volt Solar Starter Kit is a straightforward and reliable solar kit for home gardeners.
This solar start kit includes two 100-watt solar panels, a charge control, a solar adapter kit, a tray cable, a pair of branch connectors, and a set of mounting Z-brackets. This set can provide up to 800 watt hours of daily output and is designed for outdoor use with its durable, waterproof build.
This solar starter kit essentially provides everything gardeners will need to start collecting solar power; however, it will need to be paired with a suitable battery and heater to store energy and heat the greenhouse.
- Type: Solar panel
- BTUs: N/A
- Coverage area: N/A
- All-in-one starter kit
- Durable construction
- Designed for off-grid applications
- Solar panel kit only; does not include battery or heater
Get the Renogy greenhouse heater kit at Amazon, The Home Depot, or Renogy.
For permanent greenhouse structures, a ceiling-mounted heater is an attractive choice. Mounted heaters keep the heater out of the way—clear of the plant-watering splash zone and eliminating any tripping hazard. Its heavy-duty build and space-saving design make the Comfort Zone 5000-Watt Fan-Forced Industrial Heater an appealing pick.
This commercial-grade heater is hardwired in, so it requires some installation, but this design means it doesn’t need to be plugged into an outlet. It’s intended for use in poorly insulated areas, offering powerful operation ideal for larger greenhouses. Although Comfort Zone does not list its coverage area, the heater has a high 17,065 BTU rating.
A fan-forced design, variable mounting angle, and adjustable louvers help to push heat to all corners of a room. To adjust the temperature, use the simple manual knob-controlled thermostat on the front of the unit.
- Type: Electric
- BTUs: 17,065 BTUs
- Coverage area: N/A
- Ceiling-mounted design
- Powerful heating
- Rugged construction
- Fan-forced heating
- Lacks remote-controlled thermostat
- Requires installation (hardwiring and mounting)
Get the Comfort Zone greenhouse heater at Amazon, The Home Depot, Lowe’s, or Comfort Zone.
Made for small to medium-size rooms up to 200 square feet, the Vornado TAVH10 Whole Room Heater with Auto Climate is a solid choice for many home greenhouse buildings. Thanks to vortex air circulation and gentle heat, this light-duty small heater ensures that warm air is properly spread throughout the room to keep a balanced temperature without cold or hot pockets.
Users can choose between a fan-only, low (750-watt), and high (1500-watt) setting, as well as set a timer or operate the heater via a remote control. The digital display allows users to set the temperature as well as view the ambient room temperature. Like many other indoor heaters, this heater stays cool to the touch and has a safety shutoff in case of excess heat or being knocked over.
One downside, however, is that this heater isn’t specifically designed for greenhouses, so it isn’t splash-proof. Gardeners should take steps to ensure this heater isn’t exposed to water or excess humidity.
- Type: Electric
- BTUs: 5,118 BTUs
- Coverage area: 200 square feet
- Even heating
- Robust safety features
- Timer feature
- Excellent temperature controls
Get the Vornado greenhouse heater at Amazon, The Home Depot, Lowe’s, or Vornado.
Large greenhouses have higher heating needs, and the Dr. Infrared Heater DR-975 7500-Watt Electric Heater is up to the task. While the brand doesn’t share the exact coverage area for this unit, its impressive 25,597 BTU rating proves it’s a powerful choice. Like many heavy-duty industrial heaters, this model can be wall or ceiling mounted. To ensure proper coverage, it features a dynamic fan and five adjustable louvers to maximize airflow for large spaces.
For easier controls, this 7,500-watt heater features a remote-controlled thermostat. Intended for garages, factors, warehouses, and greenhouses, it has a temperature range from 50 to 90 degrees Fahrenheit. A low, high, and timer mode add even more flexibility, allowing gardeners to choose the heat intensity and select an automatic shutoff time.
- Type: Electric
- BTUs: 25,597 BTUs
- Coverage area: N/A
- Wall or ceiling mount
- Powerful operation
- Remote controlled
- Requires installation (hardwiring and mounting)
Get the Dr. Infrared Heater DR-975 greenhouse heater at Amazon, The Home Depot, Appliances Connection, or Dr. Infrared Heater.
The Bio Green Palma greenhouse heater is designed with greenhouses in mind and is packed with a range of convenient usage and safety features for hobby gardeners, including a digital thermostat, fan-forced heating, and splash-proof design. Those who want a simpler and more budget-friendly alternative can consider the Dr. Infrared Heater DR-218 greenhouse heater instead, which comes with basic temperature controls and great safety features.
How We Chose the Best Greenhouse Heaters
When considering the best heater for greenhouse use, we chose greenhouse heaters suitable for compact greenhouses—the types typically owned by home gardeners. Very large greenhouses and commercial greenhouses may have different needs. To suit different gardeners, we chose a few different heater types, from propane greenhouse heaters for small greenhouses to larger ceiling-mounted units.
The heaters in this lineup are suitable for different-size backyard greenhouses and were selected with hobbyists in mind. They are easy to set up and use, energy efficient, and low maintenance.
Robust safety features earned several heaters a spot in our roundup. We prioritized heaters that gardeners will feel safe to leave in the greenhouse while they’re not on the premises.
Tips for Keeping a Greenhouse Warm
Using a greenhouse heater isn’t the only way to keep a greenhouse warm. Thoughtful gardeners can conserve heat naturally with the practices described below, and even in cold climates where a heater is necessary, these tips can lower the amount of additional heat needed.
Insulation can do a great deal in helping a greenhouse trap heat. Some air circulation is necessary in a greenhouse, but make sure to seal unnecessary air leaks. One popular and inexpensive way to add extra insulation to a greenhouse is with Bubble Wrap. Installed across greenhouse walls and ceilings, its small air bubbles help keep heat in the building.
A heat-retaining thermal mass can also help the greenhouse maintain a higher temperature. Large barrels filled with water are a commonly used, cost-effective option. The sun heats the water throughout the day and some of that warmth is retained after the sun goes down. Heat sinks made of cinder blocks, stone, bricks, and cement are other options. A well-tended compost pile can also generate a good amount of heat, so consider moving the compost pile into the greenhouse through winter.
If these methods cannot create and maintain the desired temperature, a greenhouse heater is a reliable option for gardeners.
- Insulate the greenhouse by sealing air leaks and using Bubble Wrap to line the walls and ceiling.
- Add a thermal mass to retain heat from the sun.
- Utilize a greenhouse heater as needed.
The right greenhouse heater can help create the most suitable environment for prized plants. However, with several types of heaters on the market, it can be hard to find the best one for your needs. Still wondering whether a greenhouse heater is right for your garden? We’ve compiled a list of frequently asked questions and provided solid, common-sense answers ahead.
Q. What type of heating systems are suitable for greenhouses?
Greenhouses can be heated using central heating systems or portable heaters. For greenhouses attached to the home or within reach from home natural gas lines, connecting to the central heating system can be a suitable choice. For separate greenhouses, choose a portable electric, gas, solar, or paraffin heater.
Q. How hot is too hot for a greenhouse?
Generally speaking, above 90 degrees Fahrenheit is too hot for a greenhouse.
Q. What is the best way to heat a greenhouse in winter?
A greenhouse heater is the best way to add heat to a cold greenhouse in winter. Take steps to insulate the greenhouse to maintain the heat.
Q. What is the most efficient greenhouse heater?
A greenhouse heater connected to a solar power system is the most efficient choice.
Q. Can I use a ceramic heater in a greenhouse?
A ceramic heater can be used in a greenhouse, although it may not have sufficient heating power to maintain the temperature in a large greenhouse.