# Cold Extreme & Polar > Part of: [Climate Zones](/climate-zones.md) · Provider: [DutchGreenhouses](/) A cold extreme or polar climate zone is a high-latitude greenhouse region — the Nordics, Iceland, northern Canada, Alaska. Daylight, not temperature, is the binding limit: supplemental lighting becomes the primary production system, envelope insulation is taken further than elsewhere, and a roof snowmelt circuit is a structural requirement. ## Facts | Property | Value | |---|---| | Representative regions | Norway, Sweden, Finland, Iceland, northern Russia, Canada, Alaska categorical | | Dominant constraint | Daylight hours categorical | | Role of supplemental lighting | Primary production system rather than a seasonal top-up categorical | | Dominant operating cost | Electricity categorical | | Required winter system | Roof snowmelt circuit with heat and power redundancy categorical | Climate zones # Cold extreme & polar. Heat you can buy. Daylight in December you cannot. ## Where lighting stops being supplemental Where: Norway, Sweden, Finland, Iceland, northern Russia, most of Canada, Alaska. ## Everywhere else, lamps top up the daylight Here, for part of the year, there is barely any daylight to top up. That inverts the design. Lighting stops being a supplement sized from a seasonal gap and becomes the primary production system, with the greenhouse structure and the daylight it admits acting as the supplement for the months that have any. Which means the economics shift with it. The dominant operating cost is electricity, not gas, and the project stands or falls on what power costs at that location — which is exactly why Iceland, with cheap geothermal power and heat, grows vegetables at a latitude that otherwise makes no sense at all. ## Insulation is worth more than anywhere on this map A long, hard heating season means every improvement to the envelope compounds across more hours than it would anywhere else. Double screens are a minimum rather than an upgrade. Insulated cladding on facades and gables makes sense here even though it costs light, because in midwinter there is little light to lose and a great deal of heat. That trade runs the opposite way to the Dutch one, in a climate that superficially resembles it. ## And the roof has to survive the winter Snow load is a governing structural case, and a snowmelt circuit in the roof is not optional equipment. Melting snow before its weight approaches the design load is standard practice, and it has to keep working during exactly the weather that would knock the power out. Redundancy in heat and power is a design requirement here, not a luxury item. A failure in January is not a bad week — it is the loss of the crop. ## What we specify differently A lighting plan that leads the design instead of following it. Envelope insulation taken further than a temperate project would justify. Structure to the local snow case, with snowmelt. And a serious answer to what happens when the power fails. DutchGreenhouses® has built at these latitudes. Get in touch with your location and your electricity price — in this climate, those two numbers decide the project. From the knowledge base ## Reads you might find interesting ### Grow Like a Pro: Starting Smart, Growing Strong How Grow Like a Pro combines smart farming, CEA technology and local partnerships for eco-friendly, profitable, pesticide-free greenhouse pr Read article ### The Case for a College Greenhouse Why a college greenhouse belongs in the curriculum: teaching science, craftsmanship, business logic and sustainability, and preparing studen Read article ### The Case for a High School Greenhouse Why every high school greenhouse matters: how it makes STEM tangible, builds responsibility and teamwork, and helps students discover their Read article ### Greenhouses in Education: The Case for Schools Greenhouses in education reconnect students to reality — the full case for why every school, high school, college and trade program should h Read article ### The Origins of Greenhouse Horticulture: My Backyard A tour through greenhouse horticulture history: from 19th-century Westland fruit walls to the “City of Glass” and today’s international high Read article ### DutchGreenhouses Rebranded: A New Corporate Identity Announcing our new corporate identity — a visual style reflecting our dedication to advanced, high-quality greenhouse projects and The Futur Read article ## FAQ **Why does lighting lead the design at high latitude?** Everywhere else lamps top up available daylight. Here there is barely any daylight to top up for part of the year, so the lighting plan is sized first and the structure and its daylight admission become the supplement for the months that have any. **What makes or breaks a polar greenhouse project?** The local electricity price. Lighting is the dominant load, so the cost of power decides the business case. Iceland grows vegetables at a latitude that otherwise makes no sense because geothermal power and heat are cheap there. **Why is insulation worth more here than in a temperate climate?** A long, hard heating season means each improvement to the envelope compounds across far more hours. Double screens are a minimum rather than an upgrade, and insulated facades and gables are justified even though they cost light, because in midwinter there is little light to lose. **What happens if the power fails in January?** It is not a bad week, it is the loss of the crop — and the snowmelt circuit stops at the same time. Redundancy in heat and power is a design requirement in this zone rather than an optional upgrade. ## Related [Climate Zones](/climate-zones.md) · [Continental](/climate-zones/continental.md) · [Temperate Maritime](/climate-zones/temperate-maritime.md) · [Growlights](/growlights.md) · [Heating](/climate/heating.md) · [Energy Screens](/screening/energy-screens.md)