How Much Does a Greenhouse Cost? (Kit, Build and Running Costs)

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Greenhouse cost is two numbers: what you pay to get the structure standing, and what you pay to run it. Most price lists stop at the kit. This guide covers greenhouse prices by type and size, the cost per square foot, the extras that sellers leave out, and the actual math on heating bills, using kit prices we checked on 2 October 2026, extension-service cost data and the latest US electricity price from the EIA.

Prices in this guide render from our product data and show the range we found across retailers. They change often, so check the retailer before you buy. How we research.

How much does a greenhouse cost by type?

Kit by kit: our cheap greenhouse kits roundup covers the bottom tiers, polycarbonate greenhouse kits the middle, and glass greenhouse kits and wooden greenhouse kits the top.

Greenhouse cost per square foot

Comparing per square foot of floor shows what you are really paying for. These are our calculations from the lowest price we found for each kit on 2 October 2026, divided by its nominal floor area.

Two patterns stand out. First, small greenhouses cost more per square foot, which Purdue Extension also notes; doors, vents and ridge pieces cost the same whatever the length. Second, extension services' numbers for farm-scale structures are far lower: Kentucky State University puts high tunnels at $1.50-$5.00 per sq ft excluding labor, Purdue at $2-$7 for high tunnels and $7-$30 for climate-controlled greenhouses, and New Mexico State's DIY PVC tunnel at about $2.50. If you need space more than looks, a hoop house is the cheapest square foot you can buy; see hoop house kits.

How much does a greenhouse cost by size?

Size-specific guides: 6x8 greenhouses, 8x10 greenhouses and 10x12 greenhouses.

Hidden greenhouse costs: what the kit price leaves out

The base is the extra most owners underestimate. A kit's included steel base frame is not a foundation; it still needs to sit level and be fixed to timber, concrete or anchors. Our greenhouse foundation guide compares every option with step-by-step builds.

Example: total cost of a 6x8 starter greenhouse

A typical first-greenhouse budget, using the Palram Mythos 6x8 ($689–$889, steel base included): a treated-timber frame and gravel pad (local prices), a 4-pack of ground anchors, one automatic vent opener, a wire shelf rack and a WiFi thermometer. Those extras come to a few hundred dollars on top of the kit, before any heater.

Greenhouse running costs: heating, power and upkeep

How much does it cost to heat a greenhouse?

Heating is the biggest running cost, and the one you can estimate. University of Alaska Fairbanks Extension gives the formula: heat loss (Btu/h) = glazing surface area (sq ft) × U-value × temperature difference (°F). The surface area is walls plus roof, not the floor.

Worked example (our arithmetic): an 8x10 greenhouse with 5 ft sidewalls and a 7.5 ft peak has about 294 sq ft of glazing. With twin-wall polycarbonate (U = 0.6):

1. Peak heater size. Keeping it at 40°F (frost-free) on a 10°F night is a 30°F gap: 294 × 0.6 × 30 = 5,292 Btu/h. A 1,500 W heater gives about 5,118 Btu/h (1 kWh = 3,412 Btu), so it would be just short at that low; UAF says to size slightly over, not under.
2. A typical night. Say the average gap over a 12-hour night is 20°F: 294 × 0.6 × 20 = 3,528 Btu/h × 12 h = 42,336 Btu, or about 12.4 kWh.
3. The bill. At the US average residential price of 18.31¢/kWh (EIA, July 2026), that's about $2.27 a night, or about $68 for 30 such nights.
4. Single glazing doubles it. With single-wall polycarbonate, glass or film (U = 1.2), the same night costs about $4.55, or about $136 a month.
5. Warmer targets cost much more. Holding 60°F instead of 40°F adds 20°F to every hour's gap; in this example that roughly doubles the bill.

Your bill moves with local power prices (EIA lists Hawaii at 48.00¢ and Washington at 14.71¢ in July 2026), with daytime sun, which our example ignores, and with how well the house is sealed. A thermostat cycles the heater, so real run time depends on the weather.

Propane is the off-grid alternative. Mr. Heater rates its Portable Buddy at 0.044 gal/h on its 4,000 Btu setting and 0.099 gal/h at 9,000 Btu, so the night above would use roughly half a gallon on low, before the heat lost through the vent that unvented propane heaters require. Multiply by your local propane price. For heater choices see greenhouse heaters, and for insulation and thermal mass, the winter greenhouse guide.

Other running costs

• Fans: small exhaust and circulation fans draw little power compared with a heater.
• Heat mats: a single-flat mat such as the Jump Start MT10006 is rated at just 17 W; a 48 in mat at 107 W.
• Film replacement: hoop-house film is typically rated for 4 years.
• Wood care: wood kits such as the Yardistry need a yearly coat of water-based sealant.
• Maintenance: Kentucky State puts high-tunnel maintenance at $100-$1,000 a year at farm scale; a backyard kit is far less.

How to save money on a greenhouse

• Buy the width you need, add length later. Several lines (Palram Balance, Snap & Grow, Riverstone MONT) extend in sections.
• Choose twin-wall if you'll heat. It costs more up front but roughly halves heating cost against single glazing.
• Go hoop house for in-ground growing. It is the lowest cost per square foot by a wide margin.
• Build the base yourself. A treated-timber frame on gravel is usually the cheapest solid foundation.
• Watch seasonal sales. Costco ran the Yardistry 8x7 at $200 off in September-October 2026; Wayfair had the Palram Hybrid 6x8 well below its list price.
• Use a lean-to. A house wall saves a side and gives back heat; see lean-to greenhouse kits.
• Consider DIY carefully. Our DIY greenhouse guide shows where building beats buying and where it doesn't.