Estimate how well a tent, tarp, emergency shelter, cabin, vehicle, or survival shelter may hold warmth. This calculator factors in outdoor temperature, wind, shelter type, insulation, shelter size, people inside, ground insulation, ventilation, moisture, and a safe heat source.
Shelter size:
Larger shelters have more air volume to warm, so the same number of people or the same heat source may produce less temperature gain.
Insulation and drafts:
Wall insulation, ground insulation, wind, ventilation, and moisture are used to estimate how much warmth the shelter can retain.
Heat sources:
People add body heat. Safe added heat sources can increase the estimate, but ventilation and fire safety are always more important than warmth.
A shelter heat retention calculator helps compare tents, tarps, emergency shelters, cabins, vehicles, and survival shelters before cold-weather camping or emergency planning.
Actual warmth depends on sleeping bag rating, clothing layers, pad R-value, wind exposure, humidity, shelter pitch, ground temperature, fatigue, calories, and personal cold tolerance.
This calculator uses a practical shelter-planning estimate:
Estimated Inside Temperature = outdoor temperature + retained heat gain - condition losses
A tent may be only a few degrees warmer than outside, but wind protection, body heat, ground insulation, shelter size, and ventilation can change the difference.
Ground insulation, wind protection, dry insulation, smaller air volume, reduced drafts, and safe heat sources can all help a shelter retain warmth.
Not usually. A larger shelter has more air volume to warm, so it often feels colder unless there are more people, better insulation, or a safe heat source.
Only use heaters specifically designed for that use and follow all manufacturer ventilation and carbon monoxide safety instructions. Many heaters are unsafe inside enclosed shelters.