most efficient space heater

BLACK+DECKER™ 1,500-Watt-Max Personal Desktop Heater with Fan Setting in White

BLACK+DECKER Ceramic Oscillating Tower Heater with Remote Control, Digital LED Display, Adjustable Thermostat, 3 Heat Settings, 1500W, BHTC209, Black

ZAFRO 8,000 BTU Window Air Conditioner Cools up to 350 Sq. ft, Ultra Quiet Window AC Unit with Remote Control

Handy Heater Copper Core Tower

Cascade Portable Heater with Handle Dark Gray

EconoHome Electric Foot Warmer for Under Desk, Office or Bedroom, Energy Efficient Feet Heater with Overheat Protection, 70 Watts

Keystone 12000 BTU Window AC 115V Inverter Heat Cool

LP500APHTR LivePure 2 in 1 Clean Heat Air Purifier & Heater

R.W.FLAME 17" Electric Fireplace with Remote, Cathedral Design, Adjustable Flames, Brightness, Heat, and Overheat Protection

Karl Home 6000 BTU Wi-Fi Enabled Portable All-in-One Window Air Conditioner

Heat Storm A-1500-PHX-WIFI Infrared Heater Wi-Fi Wall Mounted White

Vie Air 1500W Portable 2 Settings Black Ceramic Heater with Adjustable Thermostat

Frigidaire Portable Neck Heater Black

ZAFRO Electric Fireplace Log Set Heater, 21" Vintage Design Portable Freestanding Fireplace Log Heater,Realistic Flames,Realistic Ember Bed for Home

Optimus 14 Inch Oscillating Dish Heater in Black

Cascade Portable Heater with Handle Goldenrod

Lasko - Electric - Ceramic - Tower Heater - 150 sq ft.

HEATDAZ Smart Air Purifier - Perfect Christmas Gift, WiFi with PM2.5 Sensor & Sleep Mode, HEPA Filter for 2050 SqFt Home

Optimus Fan Forced Tower Quartz Heater with Thermostat

BLACK+DECKER Window Air Conditioner, White

Dan’s Originals for Lasko 2033624 Space Heater Remote Control - 2033624