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The only thermostat that says what Circulate costs: the fan runs 35 per cent of the time

Honeywell Home RTH9585WF1004

A seven-day programmable Wi-Fi color thermostat with monthly energy reports and a Circulate fan mode running about 35 per cent of the time.

Honeywell Home RTH9585WF Wi-Fi smart color thermostat in grey

Honeywell Home RTH9585WF1004

A seven-day programmable Wi-Fi color thermostat with monthly energy reports and a Circulate fan mode running about 35 per cent of the time.

Type
Wall thermostat, wired to the HVAC system — not an outlet thermostat
Programming
7 day, flexible, including for utility peak-rate pricing
Display
Color touchscreen, personalisable
Fan modes
On; Automatic; Circulate — running randomly about 35% of the time
Reports
Monthly energy reports with personalized tips
C-wire
Required
Compatible with
Forced air (gas, oil or electric), hot water and steam, heat pumps with electric backup
Not compatible with
Electric baseboard heat at 120–240 V
Control
App, Amazon Alexa and Google Home
Certification
Energy Star
Amazon reference
B075BF6V58
EAN
0085267911313
  • The only thermostat on this shelf that quantifies its Circulate fan mode — about 35 per cent of the time — rather than naming it and stopping
  • Monthly energy reports with tips, which only this thermostat and its dearer stablemate publish
  • C-wire required, where three thermostats on this shelf work without one on most systems

Best for: A forced-air or hydronic house on a time-of-use tariff, with a C-wire already in the wall

≈ $110
Check price on Amazon

Specifications

Type
Wall thermostat, wired to the HVAC system — not an outlet thermostat
Programming
7 day, flexible, including for utility peak-rate pricing
Display
Color touchscreen, personalisable
Fan modes
On; Automatic; Circulate — running randomly about 35% of the time
Reports
Monthly energy reports with personalized tips
C-wire
Required
Compatible with
Forced air (gas, oil or electric), hot water and steam, heat pumps with electric backup
Not compatible with
Electric baseboard heat at 120–240 V
Control
App, Amazon Alexa and Google Home
Certification
Energy Star
Amazon reference
B075BF6V58
EAN
0085267911313

What the maker puts in writing

  • 7-day programmable, color touchscreen, Energy Star
  • Fan: On, Automatic, or Circulate at about 35% of the time
  • Monthly energy reports with personalized tips
  • C-wire required
  • Forced air, hot water, steam, heat pumps with electric backup — not electric baseboard

Thirty-five per cent

Circulate is on almost every smart thermostat and almost no listing says what it does. This one does: the fan runs about 35 per cent of the time, randomly.

That matters because the fan costs electricity. A third of the time is a real running cost, and knowing it is the difference between choosing the mode and discovering it on a bill.

The utility angle

Peak-rate programming and demand-response enrolment both appear in this listing and nowhere else on this shelf.

On a time-of-use tariff, that is where a smart thermostat actually earns its price — not from being clever, but from heating the house before the expensive hours start.

Availability

Read on the day this page was built: $110 at the American Amazon shop.

Read from Keepa on the day this page was last revised; stock and price both move without notice.

Prices quoted in this text were read on 2026-10-04. The live price is at the top of the page.

The questions that keep coming up

What is Circulate mode?

The fan runs intermittently even when the system is not heating or cooling, to even out temperatures between rooms. This listing says it runs randomly about 35 per cent of the time, which is the only duty figure published on this shelf — everywhere else Circulate is a word.

Do I need a C-wire?

Yes. The listing states it plainly and adds that some houses need a C-wire power adapter. If your wall has no common wire, the Sensi, Suuwer and riseem S3001 on this shelf all work without one on most systems.

What is a demand-response program?

An arrangement where the utility may nudge your heating or cooling setting during peak demand in exchange for a credit. This is the only thermostat on this shelf that mentions one, and it is a real source of savings on a time-of-use tariff.

More outlet thermostats

  • riseem WiFi smart thermostat with blue backlit LCD on a wall

    riseem STN701W-Blue

    A Wi-Fi single-stage wall thermostat with seven-day programming, requiring a C-wire and a 2.4 GHz network.

    Type
    Wall thermostat, wired to the HVAC system — not an outlet thermostat
    Systems
    Conventional single stage, 1 heat / 1 cool, gas oil or electric, plus air conditioning
    C-wire
    Required; cannot run on batteries
    Terminals
    RH, RC, W, Y, G, C. Does not support W2, Y2, O/B, E, L, AUX, ACC+, ACC−, S, X, X2
    Not compatible with
    2H/1C, 2H/2C, 3H/2C, 4H/2C multi-stage, heat pumps, heat-only, cool-only, 120–240 V line voltage, PTACs, mini splits, RV air conditioners
    Wi-Fi
    2.4 GHz only — stated twice
    Programming
    7 day, or none
    Accuracy
    Within 2 °F
    Size
    0.98 in D × 4.72 in W × 3.86 in H
    Amazon reference
    B0HK7QP8KC
    EAN
    0607607717210
    • Lists its supported and unsupported terminals by name, which no other thermostat on this shelf does
    • Publishes an accuracy figure and its own dimensions, both of which most of this shelf omits
    • C-wire required and no battery fallback at all — the most restrictive power requirement on this shelf

    Best for: A single-stage forced-air system with a common wire, where seven-day programming matters more than a degree of accuracy

    ≈ $50
    Check price on Amazon
  • riseem non-programmable thermostat in white with backlit LCD display

    riseem S3001-White

    A non-programmable single-stage wall thermostat accurate to ±1 °F, running on 24 V or two AA cells with no C-wire on most systems.

    Type
    Wall thermostat, wired to the HVAC system — not an outlet thermostat
    Systems
    Single-stage heating and cooling; gas, oil or electric furnace; boiler radiant; forced air; gas fireplace at 24 V; cooling only
    Not compatible with
    Multi-stage, 3-wire hydronic, heat pumps with or without auxiliary heat, dual fuel, mini splits, RV, convectors, radiant ceiling, electric baseboard at 120–240 V
    Power
    24 V AC or 2 AA batteries; C-wire needed only on heat-only and cool-only systems
    Accuracy
    ±1 °F
    Display range
    41 °F to 95 °F
    Control range
    44 °F to 90 °F
    Swing
    Separate heating and cooling cycle rate
    Installation
    Large terminal blocks, universal sub-base, within 30 minutes; 2 to 5 wires
    Warranty
    2 years, with 30-day free return
    Amazon reference
    B0DNDS8PKF
    EAN
    0607605200691
    • The only thermostat on this shelf that publishes both its compatible and its incompatible system lists
    • Publishes ±1 °F accuracy and both temperature ranges, at the joint-lowest price on this shelf for a wall thermostat
    • Non-programmable: no schedule, no app, no voice control

    Best for: A single-stage furnace or boiler where the thermostat should just hold a temperature, in a wall with no common wire

    ≈ $27
    Check price on Amazon
  • Sensi Smart Thermostat ST55 on a wall with button controls

    Sensi ST55

    A Wi-Fi smart wall thermostat that needs no C-wire in most homes, with a built-in level and a privacy pledge.

    Type
    Wall thermostat, wired to the HVAC system — not an outlet thermostat
    C-wire
    Not required in most applications
    Savings claim
    About 23% on HVAC energy
    Installation
    Built-in level and step-by-step app instructions
    Form
    Buttons, not a touchscreen; fits the footprint of a traditional thermostat
    Privacy
    The maker states it will not sell your personal information to third parties
    Maintenance
    Usage reports, equipment alerts, filter replacement reminders
    Certification
    Energy Star
    Accuracy
    Not stated by the maker
    Amazon reference
    B01NB1OB0I
    EAN
    0786710554827
    • No C-wire in most applications, which removes the single biggest installation obstacle on this shelf
    • The only thermostat here with a privacy commitment in writing, and the only one with a built-in level
    • The 23 per cent saving has no stated baseline, where the ecobee on this shelf names one

    Best for: A retrofit where the wall has no common wire and the old thermostat’s outline must not show

    ≈ $100
    Check price on Amazon

Elsewhere in the spares drawer

  • Mrrihand heavy duty waterproof air conditioner cover on an outdoor unit

    Mrrihand UPC

    A 420-denier waterproof cover for units up to 24 by 24 by 30 inches, with an air vent and side Velcro openings.

    Type
    Waterproof, sealed fabric — with an air vent
    Fits
    Units up to 24 × 24 × 30 in
    Material
    420D polyester oxford, heavy duty waterproof
    Ventilation
    Air vent, to prevent moisture and condensate build-up inside the unit
    Fixing
    Elastic hem cords; side Velcro openings that seal around a duct
    Handling
    Padded handle for fitting and removal
    Protects against
    Rain, snow, dust, sun, debris, hail
    Sizing advice
    Choose a cover 2 inches larger than the unit, as the maker recommends
    Cleaning
    Water or mild soap; not machine washable
    Included
    Storage bag
    Amazon reference
    B09DP76Z54
    EAN
    0720168356350
    • The only listing on this shelf that publishes a fabric weight: 420 denier polyester oxford
    • The only waterproof cover here with an air vent, named as preventing moisture and condensate inside the unit
    • A sealed cover traps moisture, and the air vent is an admission of the problem rather than a solution to it

    Best for: A condenser shut down for a hard winter of snow and hail, uncovered again in spring

    ≈ $27
    Check price on Amazon
  • RUNZEG waterproof air conditioner cover fitted over an outdoor unit

    RUNZEG Not stated by the maker

    A waterproof polyester oxford cover 26 by 26 by 32 inches, with a drawstring and a carrying bag.

    Type
    Waterproof, sealed fabric
    Size
    26 in wide × 26 in deep × 32 in high
    Fits
    Outdoor AC units up to 26 × 26 in; also swamp coolers, pool heaters, condensers, heat pumps and compressors of similar size
    Material
    Polyester oxford with a professional waterproof undercoating
    Fixing
    Adjustable drawstring cord
    Keeps out
    Snow, rain, wind, sunlight, dust, resin, leaves, debris, bird droppings
    Cleaning
    Damp cloth or rinse; dries in the sun
    Included
    Carrying bag
    Breathability
    Claimed as more breathable than PVC covers; no figure
    Amazon reference
    B0DG47G9F1
    EAN
    0784668670798
    • Full height at 32 inches and fully waterproof, at the lowest price on this shelf for a sealed cover
    • Names five other appliances it fits — swamp coolers, pool heaters, condensers, heat pumps, compressors — which is the widest application list here
    • It is a sealed cover: moisture that gets in cannot easily get out, and unlike the other waterproof cover here it has no air vent

    Best for: A condenser, pool heater or swamp cooler shut down for the winter in a wet climate

    ≈ $10
    Check price on Amazon
  • XINNIKESI insulated aluminum foil air conditioning pipe cover with zip

    XINNIKESI XINNIKESI

    A zipped double-layer foil and oxford sleeve for refrigerant lines from a quarter inch to one and an eighth.

    Type
    Refrigerant line cover — not a unit cover
    Fits pipe
    1/4 in to 1 1/8 in diameter
    Construction
    Double-layer aluminum foil with reinforced oxford cloth
    Closure
    Zip, universal, no tools
    Protects against
    UV damage, extreme temperatures, heavy rainfall
    Function
    Reflective foil reduces heat transfer; oxford cloth resists tearing
    Use
    Indoor or outdoor; balconies, rooftops, exterior walls
    Systems
    Window-mounted or split systems
    Length
    Not stated by the maker
    Amazon reference
    B0FVR9379C
    EAN
    7698310251965
    • The only product on this shelf for the refrigerant lines, which lose efficiency when their insulation perishes in sunlight
    • Covers a real range of pipe sizes — 1/4 to 1 1/8 inch — with a zip, so it goes on without cutting the line
    • Does not publish its length, which is the dimension you need to know how much pipe it covers

    Best for: A split system whose line insulation has gone grey and crumbly in the sun

    ≈ $17
    Check price on Amazon

All outlet thermostats