How Much Does It Cost to Heat a Greenhouse? UK Running Costs 2026
Heating a greenhouse in the UK costs £8-60 per month. A 6x8 kept frost-free with a tube heater runs £8-12 per month. The same greenhouse kept at 7°C for tender plants costs £30-45 per month. Electricity sits at 25p per kWh under the 2026 Ofgem price cap. Bubble wrap insulation cuts these figures by 30-40%.
Key Takeaways
- Most UK greenhouse owners do not need heating — an unheated greenhouse stays several degrees warmer than outside
- Frost protection is cheap — a tube heater with thermostat costs £8-12 per month for a 6x8
- Always insulate before you heat — bubble wrap cuts your bill by a third
- Electric tube heaters are the best value — low wattage, built-in thermostat, runs for pennies
Installer's Note
The number one mistake I see is customers buying a heater before insulating. A greenhouse without bubble wrap leaks heat through every pane. Fit £20 worth of insulation first. Then buy the smallest heater that keeps your greenhouse frost-free. Most people spend far less on heating than they expect.
Do you actually need a greenhouse heater?
Most UK greenhouse gardeners do not need one. An unheated greenhouse stays 2-5°C warmer than outside overnight. On sunny winter days, it can hit 15°C inside when it is near freezing outside. With bubble wrap, the overnight buffer improves further.
You only need a heater if you want to:
- Keep frost out (above 2°C) — for overwintering pelargoniums, fuchsias, and dahlia tubers
- Keep it warm (above 7°C) — for citrus trees, tender fuchsias, and early seed starting
If you only grow hardy crops from spring to autumn, save your money. Our winter greenhouse growing guide shows what you can produce without any heating.
Monthly heating costs by greenhouse size
These figures use the 2026 Ofgem electricity price cap of 25p per kWh. They assume a thermostat-controlled heater running overnight through the coldest months (December to February). Real costs vary with your local climate and how cold the winter gets.
Frost protection (keeping above 2°C)
| Greenhouse size | Without insulation | With bubble wrap |
|---|---|---|
| 6x4 (small) | £20-30/month | £12-18/month |
| 6x8 (standard) | £35-50/month | £20-30/month |
| 8x10 (large) | £50-70/month | £30-45/month |
Warm growing (keeping above 7°C)
| Greenhouse size | Without insulation | With bubble wrap |
|---|---|---|
| 6x4 (small) | £45-60/month | £28-38/month |
| 6x8 (standard) | £80-110/month | £50-70/month |
| 8x10 (large) | £120-165/month | £75-105/month |
The difference between frost protection and warm growing is significant. Keeping a 6x8 frost-free costs roughly £25 per month with insulation. Keeping it at 7°C costs around £60. That is why we always recommend starting with frost protection and adding heat only if your plants genuinely need it.
Matt's Tip: Use a tube heater, not a fan heater
Fan heaters blast hot air and cycle on and off constantly. Tube heaters provide gentle, steady warmth at much lower wattage. For frost protection in a 6x8, a tube heater draws around 120W. A fan heater draws 2,000W. The tube heater costs pennies per night. The fan heater costs pounds. I always recommend tube heaters for overnight frost protection.
Which heater type costs the least to run?
Electric tube heaters are the cheapest option for frost protection. For larger greenhouses or off-grid setups, propane gas heaters make more sense. Paraffin is the most expensive fuel per kWh.
| Heater type | Cost per kWh | Best for | Downsides |
|---|---|---|---|
| Electric tube | 25p | Frost protection, small greenhouses | Needs mains electric |
| Electric fan | 25p | Quick heat, larger greenhouses | High wattage, noisy |
| Propane gas | 19p | Off-grid, larger greenhouses | Cylinder refills, condensation |
| Paraffin | 33p | Off-grid, small greenhouses | Expensive fuel, fumes, condensation |
Propane is cheaper per kWh than electricity (19p vs 25p). But gas heaters produce moisture as they burn. This means more condensation, more fungal problems, and you need a vent open for safety. Electric heaters keep the air dry and run silently. For most greenhouse owners, electric is the better choice.
How bubble wrap cuts your heating bill
Horticultural bubble wrap with 20mm bubbles reduces heat loss by 30-40%. It lets in around 90% of light and lasts 3-5 seasons. A roll for a 6x8 greenhouse costs £15-25.
For a 6x8 greenhouse on frost protection, bubble wrap saves roughly £15-20 per month on heating. Over a 5-month winter, that is £75-100 saved from a £20 investment. Nothing else in greenhouse growing gives you that return. Our greenhouse insulation guide explains how to fit it properly.
What our heaters cost to run
Here are the actual running costs for the greenhouse heaters we sell. These are based on 25p per kWh electricity and current propane prices.
| Heater | Output | Cost per hour | Cost per 10hr night | Price |
|---|---|---|---|---|
| Elite Tube Heater (thermostat) | 2,000W max | 50p at full power | £1-2 (thermostat cycles) | £75 |
| Palram 2400W Electric | 2,400W | 60p at full power | £2-4 (thermostat cycles) | £199 |
| Eden 2KW Gas | 2,000W | 38p (propane) | £1.50-3 (thermostat) | £140 |
| Elite Paraffin | ~1,000W | 33p | £3.30 (no thermostat) | £110 |
| Elite Gas Blue Flame | 1,900W | 36p (propane) | £1.50-3 (thermostat) | £249 |
The thermostat makes all the difference. A heater running continuously at full power costs far more than one that cycles on and off. The Elite Tube Heater and Palram 2400W both have built-in thermostats. Set them to 2°C for frost protection and they only fire up when needed.
Want more heating options? See our guide on how to heat a greenhouse. For off-grid setups, read heating without electricity.
How to keep costs as low as possible
- Insulate first. Fit bubble wrap before you buy a heater. It saves 30-40% on running costs.
- Seal gaps. Check the door seal and any cracked panes. Cold draughts waste heat fast.
- Use a thermostat. Set it to the minimum temperature your plants need. Every extra degree costs money.
- Heat only what you need. If you have just a few tender plants, use a heated propagator instead of heating the whole greenhouse.
- Partition the greenhouse. Hang a curtain of bubble wrap to create a smaller heated zone.
Our winter greenhouse care guide covers all the seasonal preparation steps.
|
Matt's Pick for cheapest greenhouse heatingBest For: Frost protection in greenhouses up to 8x10 Why I Recommend It: Built-in thermostat, IP44 rated for damp conditions, and costs pennies per night on frost protection. I fit these for customers who want to overwinter tender plants without the electricity bill shock. Set it to 2°C and forget it. Price: £75 |
Frequently asked questions
How much does it cost to heat a greenhouse in winter UK?
Between £8 and £60 per month for a standard 6x8 greenhouse. Frost protection with a tube heater and bubble wrap costs £20-30 per month. Keeping temperatures above 7°C for tender plants costs £50-70 per month. Costs are based on 25p per kWh electricity under the 2026 Ofgem price cap.
What is the cheapest way to heat a greenhouse?
An electric tube heater with a thermostat is the cheapest to run. It draws low wattage and only fires up when the temperature drops below your setting. Combined with bubble wrap insulation, frost protection costs around £8-12 per month for a small greenhouse.
Is it worth heating a greenhouse in winter?
Only if you grow plants that need it. Hardy salad crops, garlic, and broad beans grow fine in an unheated greenhouse. A heater is worth it for overwintering pelargoniums, fuchsias, citrus, or starting seeds early in February. Most UK growers do not need one.
Does bubble wrap insulation really work in a greenhouse?
Yes. It reduces heat loss by 30-40%. Horticultural bubble wrap with 20mm bubbles lets in around 90% of light. A £20 roll for a 6x8 greenhouse saves £75-100 over a single winter. It pays for itself within weeks of the first cold snap.
Is electric or gas cheaper for heating a greenhouse?
Propane gas is cheaper per kWh (19p vs 25p for electricity). But gas heaters produce moisture and need ventilation. Electric heaters are cleaner, safer, and more convenient. For most hobby greenhouses, the convenience of electric outweighs the small cost saving from gas.
