Planning a furnace upgrade in the GTA? This quick 2025 guide explains realistic installed prices, the 10 factors that move your quote, and what a code-compliant install should include. Book a visit in Markham, Toronto, or anywhere in the GTA for a precise, line-item estimate. The quick take (installed pricing in the GTA) Most Greater Toronto homeowners invest about $4,000–$6,750+ installed for a high-efficiency gas furnace, depending on size, staging (single/two-stage/modula
