Replacing a home thermostat costs $140 to $350 including the unit and professional installation, according to HomeGuide, which puts labor alone at $80 to $200.[2] Angi reports a $185 national average for professional thermostat installation – most homeowners pay $114 to $265 – tied to 2,397 verified projects from Angi Pros in 2026.[1] The unit itself runs $15 to $250 depending on type, brand and features.[2]
Safety first: kill the power before touching thermostat wires. Most home thermostats use low-voltage wiring rather than standard household current, but Honeywell Home’s replacement guidance is to switch off power to the HVAC system at the breaker before handling any wires, and to follow the instructions for the exact model being installed. If the existing wiring does not match the new thermostat’s guide, or the system lacks the C-wire a smart model needs, bring in a licensed HVAC technician or electrician.[3]
Thermostat replacement cost by source
| Source | Average (per job) | Typical range (per job) | Scope as published |
|---|---|---|---|
| HomeGuide | $229 | $142 – $346 | Cost to install a thermostat, national average; page also lists an $80 minimum and $450 maximum per job |
| Angi | $185 | $114 – $265 | Professional thermostat installation; tied to 2,397 verified Angi Pros projects |
Angi and HomeGuide are separately owned publishers, and their pages state no shared sourcing. Angi’s own page frames a single-thermostat replacement as typically $120 to $350 in its by-count table, a different scope from the $114 to $265 installation range in its summary; both are reported as published. HomeGuide separately describes a like-for-like replacement as $140 to $350 including the unit and labor.
Cost by thermostat type
| Thermostat type | Unit + labor (HomeGuide, per job) |
|---|---|
| Smart | $200 – $450 |
| Wi-Fi | $170 – $400 |
| Digital programmable | $160 – $340 |
| Electronic non-programmable | $100 – $200 |
| Manual / mechanical | $80 – $190 |
Thermostat replacement cost by type, unit and labor included. Source: HomeGuide. HomeGuide’s own page disagrees with itself in places: its prices table lists smart units at $150 to $320 (versus $100 to $250 in the first table) and its prose puts a smart-thermostat install at $225 to $400 (versus $200 to $450 in the table). All versions are reported as published.
Angi publishes unit-level ranges by category as well: manual thermostats at $20 to $80, programmable models at $50 to $150, and smart or learning models at $100 to $400, and it notes that line-voltage and low-voltage systems need matching thermostat types – a compatibility check the manufacturer guidance below also stresses.[1]
Cost by number of thermostats
| Number of thermostats | Installation cost (Angi, per job) |
|---|---|
| 1 | $120 – $350 |
| 2 to 3 | $250 – $600 |
| 4 or more | $500 – $1,200 |
Thermostat installation cost by number of thermostats. Source: Angi, which notes contractors often discount per-unit labor when several thermostats are replaced in one visit.
Smart thermostat cost by brand
| Smart thermostat brand | Unit (HomeGuide, per unit) | Unit + install (HomeGuide, per job) |
|---|---|---|
| Ecobee | $170 – $240 | $270 – $440 |
| Google Nest | $150 – $249 | $250 – $450 |
| Honeywell | $99 – $229 | $200 – $430 |
| Emerson Sensi | $95 – $128 | $200 – $330 |
| Lux / Kono | $103 – $149 | $200 – $350 |
| Hive | $120 | $220 – $320 |
Smart thermostat installation cost by brand. Source: HomeGuide. Brand availability and pricing change; treat these as the published figures, not current retail quotes.
Extra costs to budget for
| Extra | Cost (HomeGuide) |
|---|---|
| Run a new C-wire | $90 – $135 per job |
| Move a thermostat | $135 – $450 per job |
| Thermostat wiring repair | $6 – $10 per linear foot (the same page’s moving section says $7 to $10 – both reported as published) |
| Drywall repair | $75 – $150 per job (factors table); the moving section prices patching the old hole and cutting a new one at $300 to $1,500+ per job |
| Smart home hub | $70 – $230 per unit |
Additional thermostat installation costs. Source: HomeGuide, with each figure kept under the scope its page published. Angi adds that permits, when a municipality requires one for larger electrical work, run $25 to $100.[1]
Do smart thermostats save money?
ENERGY STAR, the federal energy-efficiency program, reports that heating and cooling account for almost half of the average American household’s annual energy bill – more than $900 a year – and says certified smart thermostats are designed to help save energy through features like scheduling, geofencing and learning temperature preferences.[5] HomeGuide repeats a claim that certified smart thermostats save up to 15% or $180 per year, but that figure does not appear on ENERGY STAR’s current page, so it is not repeated here as fact.[2][5]
Disposing of an old mercury thermostat
Some older mechanical thermostats contain a small mercury vial.[2] The EPA says mercury thermostats are unlikely to break or leak in use but must be properly disposed of when replaced: take the old unit to a state or local household hazardous waste collection center for recycling rather than putting it in the trash.[4]
DIY or hire a pro?
Honeywell Home’s guidance: a like-for-like swap on a low-voltage system can be a DIY job if you shut off power at the breaker first, photograph the existing wiring before disconnecting anything, and follow the instructions for the exact model. It recommends professional installation when the wiring does not match the guide, when the system lacks a C-wire, or when the equipment is older or complex.[3] Both cost publishers echo the caution: HomeGuide warns an improper installation can blow out the thermostat, the HVAC unit or a breaker, and Angi notes some manufacturers require professional installation for warranty coverage.[1][2] If your swap fits the manufacturer’s DIY conditions, compare models in The Home Depot’s Thermostats category.
Related cost guides
See our guides to HVAC repair cost, AC tune-up cost, furnace repair cost, baseboard heater repair cost and heat pump repair cost.
Sources
- Angi – How Much Does Thermostat Installation Cost? (updated Sep 16, 2026)
- HomeGuide – Thermostat Replacement Cost (August 29, 2025)
- Honeywell Home – Can I Replace My Home Thermostat Myself? (manufacturer replacement guidance)
- U.S. Environmental Protection Agency – Mercury in Consumer Products (thermostat disposal guidance)
- ENERGY STAR – Smart Thermostats (federal energy-efficiency program)