Picking a thermostat that fits the equipment
The thermostat has to match what's in the basement before it matters which app you like. We look at four things first: how many heating and cooling stages the equipment has, whether there's a heat pump, whether a humidifier or ventilator should be wired to it, and whether the system is a communicating one.
Ecobee, Google Nest and Honeywell Home all make good thermostats, and all three handle a standard gas furnace with central air. They differ in how they handle remote room sensors, humidifier control and heat pump settings. Several models can run a whole-home humidifier and lower its target as it gets colder outside, which keeps frost off your windows in January. Our roundup of smart thermostats for northern climates compares them.
Communicating systems are the exception. Carrier Infinity, Bryant Evolution, Lennox's iComfort line and Trane's communicating controls send data between the thermostat, furnace and outdoor unit to run fine staging and report faults. Put a third-party thermostat on that equipment and it usually drops to basic 24-volt operation. Sometimes that's an acceptable trade. Often it isn't.
C-wires and power problems
A smart thermostat needs steady 24-volt power, and that comes from the C, or common, wire. Plenty of homes built before smart thermostats have a thin two- or four-wire cable with no C. Some thermostats try to borrow power through the heating circuit when there's no C, and on some furnaces that causes the screen to go blank, the Wi-Fi to drop, or the furnace to click on and off by itself.
The fix is either a new cable from the furnace to the thermostat or an adapter kit mounted at the furnace control board. In older Minneapolis houses with plaster walls, fishing a new cable can be the harder job, and the adapter is often the better answer. Our C-wire guide explains what the wires do.
Heat pumps and dual fuel in a Minnesota winter
This is where a wrong setting costs real money. A heat pump thermostat controls the reversing valve (the O/B wire), the compressor, and backup heat, which is either electric strips or a gas furnace on a dual-fuel system.
With electric strips, a deep overnight setback is a trap. At 6am the thermostat sees a big gap, decides the heat pump can't close it fast enough, and brings on the strips. We set smaller setbacks and an outdoor temperature lockout so the strips run only when it's truly cold.
On a dual-fuel system, the thermostat or control hands the heating over from the heat pump to the gas furnace below a chosen outdoor temperature. Where to set that point depends on your heat pump's cold-weather capacity and your gas and electric rates. An outdoor sensor makes the handoff accurate. See our heat pump page for how we size the equipment itself.
Placement: where the thermostat reads the house
A thermostat can only control the air it sits in. On an outside wall in January, it reads cold and overheats the rest of the house. Near a supply register, in the sun, or next to the kitchen, it reads warm and shuts off early. At the bottom of an open stairwell in a split-level, it catches every draft coming down.
A good spot is an interior wall at about eye level in a room you use, away from vents, windows and doors. Smart thermostats with remote room sensors can average several rooms, which helps in houses where the thermostat can't be moved easily.
Zoning with dampers
Many Minnesota houses have one furnace trying to heat floors that behave differently. A 1.5-story with a finished upstairs bakes in July and chills in January. A rambler with a finished basement has a lower level that stays cool all year. A two-story open to the entry has heat collecting at the top.
Zoning splits the ductwork with motorized dampers, gives each area its own thermostat, and uses a zone panel to open and close dampers as each zone calls. It works best with a two-stage or variable-speed furnace and blower, so the system can slow down when one small zone is calling alone. On a single-speed system, we have to plan for where the extra air goes, or the ducts get noisy and the furnace runs hot.
Boilers zone more simply, with a zone valve or circulator per loop. Before recommending zoning, we check for the simpler causes of uneven heat covered in our post on zoning systems: missing returns, closed dampers and leaky ducts.
How much does thermostat installation cost?
A thermostat or zoning service call is a $79 trip charge, waived when you approve the repair, and pricing is the same in every town we serve. New thermostats, C-wire runs, relocations and zoning systems are quoted in writing at a flat rate before we start, and completed repairs carry a 1-year parts-and-labor warranty. For a sense of scale, national cost guides such as HomeGuide put a typical installed smart thermostat at $225–$400, plus $90–$135 when a C-wire has to be run, and a two- or three-zone retrofit zoning system at $1,700–$3,500.
Utilities sometimes help with the thermostat itself. CenterPoint Energy offers a thermostat rebate, and Xcel Energy's AC Rewards program pays an annual reward for enrolling a smart thermostat in its summer demand response. Check each utility's page for current terms. If you're replacing a furnace or adding a heat pump, sort out the thermostat wiring at the same time. Call 612-429-3465 to book.
What's included with smart thermostats & zoning?
- Wiring check at the thermostat and at the furnace, boiler or air handler
- A new cable or an adapter when the existing wire is short a conductor
- Heat pump, backup heat and dual-fuel settings configured
- Placement check, with relocation when the current spot reads wrong
- Zoning layout with dampers, a zone panel and a thermostat per zone
- Schedules and app setup walked through before we leave
- Written, flat-rate price before any work starts
Smart Thermostats & Zoning questions
What is a C-wire and do I need one?
The C, or common, wire completes the 24-volt circuit so a thermostat has steady power. Most smart thermostats need one. Many older homes have only two or four wires and no C, and the thermostat tries to borrow power through the heating circuit, which can cause blank screens or a furnace that cycles oddly. We run a new cable or install an adapter kit at the furnace.
Can I use a smart thermostat with a heat pump in Minnesota?
Yes, if it's set up for heat pumps. The thermostat has to control the reversing valve, the backup heat, and on dual-fuel systems the handoff to the gas furnace below a chosen outdoor temperature. Deep overnight setbacks can make a heat pump call for strip heat in the morning, so we usually recommend smaller setbacks plus an outdoor temperature lockout.
Should I swap my Carrier or Lennox communicating thermostat for an Ecobee?
Think twice. Communicating systems such as Carrier Infinity, Bryant Evolution and Lennox's iComfort controls talk to the furnace and outdoor unit over a data connection and use it for fine staging and diagnostics. A third-party thermostat usually has to run that equipment in basic 24-volt mode, which gives up part of what you paid for. See whether the manufacturer's own app covers what you want first.
Where should a thermostat go?
On an interior wall at about eye level, in a room you use, away from supply registers, sunny windows, the kitchen, exterior doors and stairwells that pull cold air. A thermostat on a cold outside wall or near a drafty entry makes the furnace overheat the rest of the house. If yours sits in a bad spot, moving it is often cheaper than living with it.
Can zoning fix a hot upstairs?
Often it helps. A zoning system splits the ductwork with motorized dampers so each floor gets its own thermostat, and a control panel opens and closes the dampers as each zone calls. It works best with a two-stage or variable-speed system that can slow down when one small zone is calling. Sometimes the real cause is a missing return upstairs, and zoning won't fix that.
Will a smart thermostat work with my boiler?
Most will on a hot-water boiler, but many boiler controls don't provide a C-wire, so plan on an adapter or a new cable. A zoned boiler needs one thermostat for each zone valve or circulator. Radiant floors respond slowly, so an aggressive setback schedule does more harm than good there. A steady setpoint, or a thermostat with a radiant setting, works better.
Sources
- HomeGuide cost guides (2026 editions) homeguide.com