Best Greenhouse Heaters UK 2026: 5 Frost Protection Picks
8 min read · Updated August 26, 2026 · By Sam Baker
- Best for large greenhouses: Trendi Large 4.5L Paraffin Heater - high heat output for spaces up to 12 square metres
- Best budget option: Fireside Paraffin Anti-Frost Heater - reliable frost protection at a low price
- Best for cold frames: Parasene Large Cold-Frame Heater - compact design for small growing spaces
- Best electric option: Hylite Slimline Ecoheater Tube Heater - energy-efficient with built-in thermostat
- Best for small greenhouses: Equip247uk Paraffin Greenhouse Heater - compact single-burner for tight spaces
Suggested Reading: Preparing Your Greenhouse for Autumn · Greenhouse vs Polytunnel
Quick Picks
🏆 Best Overall
Trendi Large 4.5L Paraffin Heater💰 Best Budget
Fireside Paraffin Anti-Frost Heater⚡ Best Electric
Hylite Slimline Ecoheater🌱 Best for Cold Frames
Parasene Large Cold-Frame HeaterQuick Comparison
| Product | Type | Coverage | Key Feature | Best For |
|---|---|---|---|---|
| Trendi 4.5L Paraffin | Paraffin | Up to 12m² | 4500W heat output | Large greenhouses |
| Fireside Anti-Frost | Paraffin | Up to 6m² | Budget-friendly | Small-medium greenhouses |
| Parasene Cold-Frame | Paraffin | Up to 4m² | Compact design | Cold frames, cloches |
| Hylite Ecoheater | Electric | Up to 8m² | Built-in thermostat | Any greenhouse with power |
| Equip247uk Paraffin | Paraffin | Up to 4m² | Single burner, compact | Small greenhouses |
In-Depth Reviews
1. Trendi Large 4.5L Paraffin Super Warm Heater
Paraffin · 4.5L tank · Up to 12m² coverage · 4500W heat output
The Trendi Large is the most powerful paraffin heater on this list, designed for greenhouses up to 12 square metres. Its 4.5-litre tank means fewer refills during cold snaps, and the single-burner design produces enough heat to keep frost off tender plants through a British winter night.
Reviewers on Amazon note the heater is straightforward to set up and lights easily. The sturdy steel construction feels durable, and the wide base gives it stability on greenhouse staging. One Amazon reviewer noted: "Lit it at 6pm and it was still going strong at 7am - kept the greenhouse above freezing even on a -3C night."
Pros
- Large 4.5L tank for extended burn time
- High heat output for bigger greenhouses
- Simple to light and maintain
Cons
- Produces some fumes during initial lighting
- Needs ventilation in sealed greenhouses
- Paraffin not included
2. Fireside Paraffin Anti-Frost Heater
Paraffin · Single burner · Up to 6m² coverage · Budget-friendly
The Fireside Anti-Frost is a no-frills paraffin heater that does exactly what it promises: keeps frost off your plants. At a lower price point than most competitors, it is the go-to choice for gardeners who need basic frost protection without spending much. The single-burner design suits small to medium greenhouses up to about 6 square metres.
Amazon purchasers praise its reliability and ease of use. The simple ignition system means you can have it running in minutes. Several reviewers mention using it successfully in unheated greenhouses through winter, with one noting it maintained temperatures "a few degrees above freezing" even on the coldest nights.
Pros
- Low purchase price
- Simple, reliable design
- Good for small-medium greenhouses
Cons
- Lower heat output than premium models
- Smaller fuel tank needs more frequent refills
- Basic construction
3. Parasene Large Cold-Frame Heater
Paraffin · Single burner · Up to 4m² coverage · Compact form factor
The Parasene is purpose-built for cold frames, cloches, and small growing spaces where a full-size greenhouse heater would be overkill. Its compact dimensions fit inside standard cold frames, and the single burner produces enough heat to protect seedlings and cuttings from overnight frost.
Amazon reviewers highlight its compact size as the main advantage. One purchaser noted: "Fits perfectly inside my cold frame and keeps the temperature just above freezing. Much better than wrapping everything in fleece." The build quality is solid for the price, with a stable base that resists tipping.
Pros
- Fits inside standard cold frames
- Compact and lightweight
- Good for seedlings and cuttings
Cons
- Too small for full-size greenhouses
- Limited heat output
- Needs frequent refilling in very cold weather
4. Hylite Slimline Ecoheater Tube Heater
Electric · 55W · Built-in thermostat · Wall-mountable · Up to 8m²
The Hylite Slimline is the standout electric option for greenhouse heating. At just 55W, it costs roughly 2p per hour to run, making it the cheapest heater to operate on this list. The built-in thermostat means you set it and forget it - it switches on when the temperature drops and off when it rises, saving energy while keeping plants protected.
The wall-mountable design keeps it off the floor and out of the way. Amazon reviewers praise its quiet operation and low running costs. One reviewer noted: "Mounted it on the greenhouse frame in October and haven't touched it since. The thermostat does all the work and our electric bill barely noticed it." The slim profile means it does not take up valuable staging space.
Pros
- Very low running cost (55W)
- Built-in thermostat for automatic control
- Wall-mountable, saves floor space
Cons
- Requires mains electricity supply
- Lower heat output than paraffin heaters
- Higher upfront cost
5. Equip247uk Paraffin Greenhouse Heater
Paraffin · Single burner · Up to 4m² coverage · 41cm height
The Equip247uk is a straightforward single-burner paraffin heater designed for small greenhouses and cold frames. At 41cm tall and 30cm wide, it fits easily into compact spaces. The simple construction means there is little to go wrong, and replacement parts are widely available.
Amazon purchasers describe it as "basic but effective" for frost protection in small growing spaces. It is not going to heat a large greenhouse, but for a 6x4 foot lean-to or a cold frame with tender seedlings, it does the job without fuss. The low price makes it a sensible choice for gardeners who want a simple backup heater.
Pros
- Very affordable
- Compact dimensions for tight spaces
- Simple, reliable design
Cons
- Limited to small spaces only
- Basic construction quality
- No thermostat or temperature control
How to Choose a Greenhouse Heater
Picking the right greenhouse heater comes down to three things: your greenhouse size, whether you have mains electricity, and how cold your winters get. Here is what to consider before you buy.
Paraffin vs Electric
Paraffin heaters are the traditional choice for UK greenhouses. They work without electricity, produce gentle warmth, and cost little to run. The trade-off is that they need manual lighting and refuelling, produce some fumes, and do not offer precise temperature control. Electric heaters, particularly tube heaters with built-in thermostats, give you automatic temperature regulation and zero emissions inside the greenhouse. They cost more to buy but offer peace of mind for overnight protection.
Greenhouse Size
Match the heater to your greenhouse floor area. A rough rule of thumb is 100 watts per square metre for frost protection. A 6x8 foot greenhouse (about 4.5 square metres) needs roughly 450W of heat output. Paraffin heaters do not have a watt rating, so compare their stated coverage area to your greenhouse dimensions. When in doubt, size up - an oversized heater with a thermostat wastes less energy than an undersized one running flat out.
Safety and Ventilation
Paraffin heaters need ventilation. Never use one in a completely sealed greenhouse - cracked vents or a slightly open door is enough. Electric heaters produce no fumes and are safer for enclosed spaces, but make sure the electrical connection is weatherproofed and the heater is mounted away from water sources.
Running Costs
Paraffin costs roughly 15-25p per hour depending on the heater and fuel price. A 55W electric tube heater costs about 2p per hour at current UK electricity rates. For occasional overnight frost protection, paraffin is cheaper. For continuous winter heating, electric with a thermostat is more economical because it only runs when needed.
Frequently Asked Questions
Final Verdict
For most UK gardeners, the Trendi Large 4.5L Paraffin Heater offers the best balance of heat output, tank capacity, and price. It handles medium to large greenhouses without fuss and keeps running through the night on a single fill.
If you have mains electricity in your greenhouse, the Hylite Slimline Ecoheater is the smarter long-term investment. Its thermostat means you never waste fuel, and at 55W it costs almost nothing to run through a full winter.
For gardeners on a tight budget or those protecting a small cold frame, the Fireside Anti-Frost Heater does the job at the lowest price. It is not fancy, but it keeps frost off your plants, which is all you need.
Products mentioned in this guide
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Sam Baker
Garden Tools Writer at MyLushGarden
Sam writes about garden tools and equipment for MyLushGarden, comparing products for real UK conditions. He has used and broken enough strimmers and secateurs to know which specs matter and which are marketing.
As an Amazon Associate, MyLushGarden earns from qualifying purchases. Product prices and availability are accurate as of the date shown and may change. We compared these products using Amazon purchaser reviews, manufacturer specifications and independent feedback.