Warranty

How To Select The Right Size Heater

Conﬁrm Your Voltage

Before selecting an electric heater, determine if the power supply is 120 volt or 240 volt.

How to check your voltage:

• The most accurate way to check your voltage supply is with a voltmeter.

WARNING: This test needs to be performed with the circuit breaker ‘On’. If you are uncomfortable working with live electrical circuits,

please consult an electrician.

• If you're replacing an old heater, identify voltage on the old heater label.

• Check your circuit breaker to identify either Single Pole 120 volt or Double Pole 240 volt.

Size Your Heater – Room Wattage Requirements

Simply follow the chart below to determine the wattage requirements for a particular room.

Step 1: Measure your room

Select the square footage closest to the room size you want to heat.

• Rooms with greater than average window space, increase wattage by 50%

• If wattage recommendation falls between two heaters, select the heater with higher wattage

Step 2: Age of Home

• Refer to the column with the age of your home.

General Requirements:

King Electric recommends approximately 6 watts per square foot for newer homes and 10 watts per square foot for older homes. It is

recommended to add 2 watts per square foot for homes located in higher than average elevations or extreme cold climates.

(BTU = WATTS X 3.412)

*Newer home - Mostly 1980’s to present, R19 walls, R30 ﬂoors and ceilings, standard windows thermal pane, 8 ft ceilings

**Older home - Prior to 1980, R11 walls, R19 ceilings, single pane windows, 9 ft ceilings

Wattage Selection Guide

Square Footage of Room Newer Home Watts* (6W/SqFt) Older Home Watts**(10W/SqFt)

50 300 500

75 450 750

100 600 1000

125 750 1250

150 900 1500

175 1050 1750

200 1200 2000

225 1350 2250

250 1500 2500

275 1650 2750

300 1800 3000

325 1950 3250

350 2100 3500

375 2250 3750

400 2400 4000