Part of The Complete Guide to HVAC Maintenance
System size (tonnage)
Bigger homes generally need higher-capacity systems, but size should be based on a proper load calculation, not just square footage. An oversized system costs more upfront and cycles inefficiently; an undersized one runs constantly and still can't keep up.
Efficiency rating
Higher SEER (cooling) and AFUE (heating) ratings cost more upfront but lower monthly operating costs. The right tradeoff depends on your climate and how long you plan to stay in the home.
Ductwork condition
If your existing ducts are leaky, undersized, or poorly laid out, replacing or modifying them adds meaningfully to the project — and skipping that step often means the new system never performs the way it's rated to.
Single-stage vs. variable-speed equipment
Basic single-stage systems are the least expensive. Two-stage and variable-speed systems cost more but run quieter, more efficiently, and manage humidity better.
Labor and local permitting
Installation complexity (attic vs. closet vs. basement units), local permit requirements, and regional labor rates all affect the final number more than most homeowners expect.
The honest answer on price
Because these factors vary so much by home and region, any specific number quoted online should be treated as a rough starting point, not an estimate for your house. Getting two or three quotes from licensed contractors for your specific home is the only way to get a number you can actually plan around.
Know your system's real age first
Hive Health tracks equipment age so you know whether you're planning a replacement or a repair.