Plan patio lounges with realistic comfort targets always. Pick heaters, windbreaks, and seating layouts smartly. Save results as files and share with your team.
| Scenario | Ambient | Wind | Enclosure | Target | Suggested Output | Expected Zone |
|---|---|---|---|---|---|---|
| Hedge-screened patio, four seats | 12°C | 10 km/h | Partial | 20°C | 6–9 kW | Comfortable |
| Open deck, breezy evening | 8°C | 20 km/h | Open | 20°C | 12–18 kW | Mild → Comfortable |
| Covered nook, low wind | 14°C | 5 km/h | Enclosed | 21°C | 3–5 kW | Warm |
| Fire pit circle, short distance | 10°C | 8 km/h | Partial | 19°C | 8–14 kW (delivered varies) | Mild |
Outdoor seating warmth depends on air temperature, humidity, and wind at seat height. The calculator converts units, estimates a feels-like temperature, then adds small comfort bonuses for clothing level, blankets, and nearby people. Enter readings taken close to your seating area, because patios can be several degrees cooler than sheltered doors or walls.
Heater demand scales with footprint. Use length and width for rectangular lounges, or total area for curved benches and mixed seating. A larger footprint spreads radiant heat, so the same heater can feel “balanced” in a nook but “undersized” across an open dining set. Keep the target comfort constant when comparing layouts.
Wind strips heat quickly by increasing convective loss. Selecting partial or full windbreak reduces effective wind, while enclosure level reduces heat loss further. In practice, a covered corner with partial walls often needs far less output than a fully open deck at the same ambient temperature. Use these settings to test whether adding screens can replace buying a bigger heater.
The sizing model estimates heat load with Q = Area × Ueff × ΔT, where Ueff rises with wind and drops with enclosure and overhead cover. The recommended output applies a safety factor for gusts and uneven distribution, then divides by heater efficiency. Electric radiant usually delivers more usable warmth near seats, while fire pits lose more energy to open air. For quick checks, 1 kW equals about 3,412 BTU/hr. Many patio heaters range from 4 to 14 kW equivalent, but comfort depends on distance, shielding, and airflow patterns.
Warmth zones translate predicted comfort into actions. “Very Cold” suggests stronger shielding, higher output, or closer placement. “Mild” and “Comfortable” suit longer gatherings, especially with blankets. “Warm” and “Hot” indicate you should increase distance, lower output, or improve ventilation. Export CSV to compare scenarios, and use the PDF for simple sharing and approvals for repeatable planning decisions consistently.
It is a practical label based on predicted comfort temperature: Very Cold, Cool, Mild, Comfortable, Warm, or Hot. Use it to decide whether to add shielding, change heater placement, or adjust output.
If you already own a heater, enter its output to see an estimated coverage label and comfort lift. If you are shopping, leave it blank and use the recommended output to shortlist options.
Radiant heat weakens quickly as seats move away from the source. Enter the typical seat-to-heater distance so the calculator can reduce delivered warmth and avoid overestimating comfort.
Windbreak reduces wind speed, while enclosure reduces overall heat loss by limiting airflow around the seating area. Using both often produces a larger comfort gain than increasing heater size.
Use 1.10–1.25 for sheltered patios, 1.30–1.50 for open or gusty sites, and up to 1.75 for very exposed layouts. Higher factors add margin but can oversize heaters once shielding improves.
Exports use your latest calculation stored for the current browser session. Click Calculate, then use the CSV or PDF buttons. Recalculate after changing any input to refresh the downloadable results.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.