How many BTU by floor area?
Updated October 24, 2026
The heating load for each floor area from 150 to 3,000 sq ft, using the CSA F280 method. Pick your floor area to see the details by city and house age.
| Floor area | 1990–2010 | Before 1970 | Recommended system (1990–2010) | DIY price |
|---|---|---|---|---|
| 150 sq ft | 2,300 | 3,300 | ZERO 9,000 wall unit | $2,199 |
| 200 sq ft | 3,000 | 4,000 | ZERO 9,000 wall unit | $2,199 |
| 250 sq ft | 3,800 | 4,900 | ZERO 9,000 wall unit | $2,199 |
| 300 sq ft | 4,500 | 5,500 | ZERO 9,000 wall unit | $2,199 |
| 400 sq ft | 6,000 | 7,000 | ZERO 9,000 wall unit | $2,199 |
| 500 sq ft | 7,500 | 8,000 | ZERO 9,000 wall unit | $2,199 |
| 600 sq ft | 9,000 | 9,400 | ZERO 9,000 wall unit | $2,199 |
| 700 sq ft | 10,500 | 10,700 | ZERO 12,000 wall unit | $2,349 |
| 800 sq ft | 15,300 | 29,200 | ZERO 18,000 wall unit | $2,895 |
| 900 sq ft | 16,600 | 31,900 | ZERO 18,000 wall unit | $2,895 |
| 1,000 sq ft | 18,000 | 34,400 | ZERO 18,000 wall unit | $2,895 |
| 1,100 sq ft | 19,300 | 37,000 | ZERO 24,000 wall unit | $3,399 |
| 1,200 sq ft | 20,500 | 39,400 | Z-PRO 27,000 · 2 zones | $4,725 |
| 1,300 sq ft | 21,500 | 41,500 | Z-PRO 27,000 · 2 zones | $4,725 |
| 1,400 sq ft | 22,700 | 43,900 | Z-PRO 27,000 · 2 zones | $4,725 |
| 1,500 sq ft | 24,000 | 46,300 | Z-PRO 27,000 · 2 zones | $4,725 |
| 1,600 sq ft | 25,200 | 48,600 | Z-PRO 27,000 · 2 zones | $4,725 |
| 1,800 sq ft | 27,000 | 51,500 | Z-PRO 27,000 · 2 zones | $4,775 |
| 2,000 sq ft | 30,000 | 55,600 | Z-PRO 36,000 · 2 zones | $5,325 |
| 2,200 sq ft | 33,000 | 59,800 | Z-PRO 36,000 · 3 zones | $5,575 |
| 2,400 sq ft | 36,000 | 63,400 | Z-PRO 36,000 · 3 zones | $5,575 |
| 2,600 sq ft | 39,000 | 67,400 | Z-PRO 36,000 · 2 zones + ZERO 12,000 wall unit | $7,674 |
| 2,800 sq ft | 42,000 | 71,000 | Z-PRO 36,000 · 2 zones + ZERO 12,000 wall unit | $7,674 |
| 3,000 sq ft | 45,000 | 74,900 | Z-PRO 36,000 · 2 zones + ZERO 12,000 wall unit | $7,674 |