most efficient space heater

VOLTORB 3-Sided Flame View Infrared Quartz Heater Stove, Free Standing Electric Fireplace for Indoor Use w/Remote Control & Programmable Timer, Black

White-Rodgers 70 Series, 7-Day PTAC Programmable Thermostat, 1F75P-21PR

Cascade Portable Heater with Handle Dark Gray

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

White-Rodgers 70 Series, 7-Day Programmable Thermostat, Heat Pump (2H/1C), 1F75H-21PR

ROVSUN 1500W Wall Heater with Remote, Freestanding & Wall-Mounted Electric Space Heater with Handle, Timer for Indoor, Bedroom

Garage/ Shop Ceiling Mount Utility Heater

ZAFRO Electric Fireplace Heater 17" , Different Flame Effects, Adjustable Brightness and Heating Mode, Overheating Safe Design

EZ Heat Portable Fireplace Fan Heater, 1200W Compact Design with Realistic Flame Effect

Cascade Portable Heater with Handle Black

Dehumidifier for Home - Perfect Christmas Gift, 1800 Sqft Dehumidifier for Bedroom/Basement, 3 Modes & 24H Timer, White Holiday Gift

White Rodgers Heating and Cooling Push Buttons Single Pole Thermostat

Optimus Portable Oscillating Ceramic w/Thermostat Heater Grey

Pelonis 22'' Digital Convertible Ceramic Tower Heater

Bestier Electric Fireplace Heater 24.25" with Remote, Adjustable Brightness and Heating Mode, Flame Effects & Log Colors

Costway 60'' Electric Fireplace Recessed Ultra Thin Wall Mounted Heater Multicolor Flame

Portable Oscillating Fan Heater with Thermostat

HEATDAZ 2-Pack Air Purifier with Essential Oil Diffuser - Perfect Christmas Gift, 108 Sqft Bedroom Air Purifier & Aromatherapy, Holiday Gift Set

Comfort Glow Electric Indoor & Outdoor All Seasons Fan and Heater With 2 heat settings

LG Electronics 12000 BTU Window Air Conditioner Heater

Portable Oscillating Ceramic Heater with Thermostat

Optimus Portable Oscillation Ceramic Heater w/ Thermostat & LED