Greenhouse Winter Heating Calculator

Estimates only. These are calculated engineering estimates, not measured performance data and not a manufacturer specification. Canada Greenhouse Kits makes no representation, warranty or guarantee that any greenhouse will reach or hold a given temperature, or that your energy use or cost will match these figures.

Your actual consumption will often be higher. The lower figure assumes a sheltered, well-sealed greenhouse. It excludes wind and site exposure, air leakage beyond 1.5 air changes per hour, gaps or an unsealed base, doors and vents being opened, heat lost to the ground, aged or damaged glazing, and thermostat placement and cycling losses. The upper figure adds 40 percent to allow for these. An exposed, windy or draughty site can exceed even the upper figure.

The calculation. Glazed surface area × the glazing’s published heat-loss rate, plus air leakage, divided by 1500 W and capped at 24 hours a day. Dimensions come from published Palram-Canopia specifications; Bella’s eave height is estimated. Hexagonal models are modelled as a regular hexagon with a pyramid roof; the Lean-To as a mono-pitch against a heated house wall that loses no heat; the T-shaped Victory and Triomphe as plain rectangles, which understates their glazed area. No solar gain or thermal mass is credited.

Weather is a 30-year average, not a forecast. Temperatures are Environment Canada climate normals. Any individual winter, cold snap or local microclimate will differ, sometimes greatly.

Electricity prices change. Rates are the published marginal energy charge at the time this page was built and exclude taxes, fixed monthly service charges, delivery variations, tier changes and differences between rate plans. Check your own bill and utility for current pricing.

Use at your own risk. This is not professional engineering, electrical or horticultural advice. Have a licensed electrician confirm your supply before installing any heater. To the fullest extent permitted by law, Canada Greenhouse Kits accepts no liability for any loss or damage, including higher-than-expected energy costs, plant or crop loss, or equipment damage, arising from reliance on this calculator.