Heating / Cooling |
Heating / Cooling
What you can grow in your greenhouse is only limited by warmth in your greenhouse. First, select an energy source. Electric heaters are generally less expensive to purchase and work well when you have electricity to your site. (Extension cords are not a good idea in a greenhouse setting and could prove unsafe.) Another option is gas heaters, either natural gas or propane, as they are inexpensive to operate and require no electricity.
If your goal is over-wintering plants, you will only need to keep your greenhouse above freezing. If you plan to get an early start with seedlings, you will need a more consistent and constant heat supply.
Heaters are rated by the amount of BTU (British Thermal Units) they produce. To determine the correct size of heater, you'll need to determine the size of your greenhouse, the expected minimum outside temperature for your area, and the minimum temperature you want to maintain in the greenhouse.
Do This |
Formula |
Example |
| Find the total SF of exposed surface area of your greenhouse. | 288 |
(Using 4' x 8' Solexx™ panels) 9 panels would be 9 x 32 = 288 s.f. |
| Determine the maximum inside temperature you want to keep your grenhouse. | 60 |
Your growing seedlings, so you want the inside temperature to stay at 60° F |
| Determine the minimum outside temperature you expect for your area. | 20 |
You live in northern California and you expect temperatures to be down to 26° F this winter |
| Determine the heat loss factor for the greenhouse covering material. | .8 |
Corrugated plactic has a heat loss value of .8. |
| Multiply the S.F. by the difference in temperatures, then by the heat loss factor. | 288x40x.8= 9216 |
The total s.f. of the covering surface area is 288. The temperature difference is 40° F. The heat loss factor is .8. |
| 9216 is the minimum BTU rating to keep your greenhouse at the desired temperature during the coldest time of the year. The HH-10 electric heater provides 5120 BTU's to heat your greenhouse. It would take 2 of those during the coldest periods. | ||
Heating |
Model # |
Description |
Retail |
||
 |
HH-10 | Portable Electric Heater - Durable, thermostatically-controlled heater will keep greenhouse warm and plants safe from frost. Anti-freeze setting, tip-over switch, overload circuit and caution light provide extra safety. Low to high knob lets you adjust the heater to your desired temperature so it operates only when needed to conserve electricity. Heavy-duty fan distributes heat throughout your greenhouse. Maximum 5120 BTUs with a 1500 watt, 1300 watt, or fan only setting. Requires 120v three-prong outlet. Measures 10" x 16" x 9.5", 6' cord. | $69.95 |
||
 |
HH-60 | Portable Propane Heater - No Power? Go Propane! Receive instant warmth in your greenhouse with this easy-to-move propane heater. Complete with oxygen sensor and accidental tip-over shut off for your safety. Generates 4500 to 8000 BTUs/hour. Requires one propane cylinder or attach a hose to a larger tank (not included.) These units are also great to have in your shop. 15" x 15" x 7.5". | $139.95 |
||
| HH-70 | LP adaptor hose - 3 ft. | $21.95 |
|||
 |
HH-50N | SB Vented GH Heater 25,000 BTU Natural Gas | $599.00 |
||
| HH-50P | SB Vented GH Heater 25,000 BTU Propane | $599.00 |
|||
 |
|
|
$269.00 |
||
Cooling |
Model # |
Description |
Retail |
||
| Cooling will be best accomplished with shade cloth, ventilation, and location for many climates. A small window air conditioner or evaporative cooler can also be utilized in certain situations. There are also some freestanding portable units available. At present we do not have any available to provide, but we're looking. | |||||
 |
Black Polypropylene shade cloth filters out excess sunlight to reduce heat on hot summer days. Lower inside temperatures help protect your special plants and help prolong the life of your greenhouse panels. Reinforced, hemmed edges with grommets on the standard shade cloth make attachment and removal easy. Special order sizes are available. | ||||
| HV-90 | Black Shade Cloth (polypropylene) 4' X 8' | $35.00 |
|||
| HV-91 | Black Shade Cloth (polypropylene) 8' X 10' | $55.00 |
|||
| HV-92 | Black Shade Cloth (polypropylene) 8' X 12' | $65.00 |
|||
| HV-93 | Black Shade Cloth (polypropylene) 8' X 16' | $85.00 |
|||
| HV-94 | Black Shade Cloth (polypropylene) 12' X 12' | $95.00 |
|||
| HV-95 | Black Shade Cloth (polypropylene) 12' X 16' | $125.00 |
|||
| HV-100 | Silver Aluminet Shade Cloth 14' wide (per linear foot) | $6.50 |
|||