Picture of a typical installation of an electric baseboard heater in bathroom.

Installing Baseboard Heaters Tips, Help, Instructions

Installing baseboard heaters can be a fun project.  Why? Because it’s not too advanced (and therefore, not too disheartening). Then after it’s done, you get a much warmer room for your winter time naps.

The theory of operation is easy to understand, and even the complexities of digital thermostats has been hidden from the end user for the most part.  So, if you have some motivation, enjoy working with electricity, and own / rent a place with a room that’s always cold, then a project like this is just what the doctor ordered.  That room will be cold no more.

We’ve installed baseboard heating in two bedrooms over the years, and lived in a few apartments that featured it.  Our own experiences installing it are described in this piece.  The thought processes and procedures we employed occurred roughly as follows, and while each installation is different, we hope the tips and hints below will help you to zero in on the most useful techniques for your particular situation.  This is how WE did it, but not necessarily how YOU should do it.

First, it’s helpful to spend a few hours just thinking about the project, to get a feel for it, and to develop a sense of how your installation will play out.  To get your creative inspirations going, the tips in the next section can focus you on the right issues and concerns.

Picture of a bedroom installation of electric baseboard heating. Installing baseboard heaters.
Baseboard heater in bedroom. Installing baseboard heaters.

Installing Baseboard Heaters Warnings and Disclaimers

We offer this article for informational and entertainment purposes only.  It does not, nor should it, take the place of advice and assistance from a qualified electrician.  Always seek professional help if you’re unsure of how to proceed, or if you doubt the veracity of the information herein.  We cannot assume responsibility for incorrectly wired baseboard heaters that result in property damage, personal injury, or death.

Warning

When installing baseboard heaters,  you work with high voltages (220 volts).  If you’re at all uncomfortable with this, then you should not do this alone. Get an electrician or other qualified person(s) to he;[.  Touching live wires can kill you.  So be cautious, careful, and constantly vigilant.  Check, double check, and triple check your work; especially when adding a new circuit inside your circuit breaker box.

Also, check and recheck that a circuit you’re working on is still turned off; especially if you live with others, who could turn the breaker on without your knowing.  Finally, anytime you leave the wiring task for hours or days, and then return to it, check again that the circuit is still OFF.  After all, you’ll want to be alive to enjoy your new baseboard heater installation.  Take extreme care, and be familiar with federal, state, and local wiring codes.

We suggest 220-volt electric heaters.  For a given amount of heat, these require less current (about half as much as their 110-volt counterparts).  So, they cause less severe voltage fluctuations throughout the rest of the house when they kick on.  Further, 110-volt heaters generally only create about 1500 watts of heat, max. This however, is insufficient for heating larger rooms with more than one exterior wall (like rooms in the corner of a house).

Installing Baseboard Heaters Project Planning

While laying out your project, ask yourself the following questions, and discuss with knowledgeable friends if you do not know some of the answers.

Is you Electrical Service Large Enough for Baseboard Heat?

We recommend a minimum 200-amp service drop; not necessarily because a 100-amp would not provide enough “juice,” but rather, because of the light dimming effects when you add high-current devices to lesser capacity services.  The larger your incoming wiring from the utility pole is, the less will be this effect.  For 60 or 100 amp sized power panels, a 10 or 15 amp electric heater system turning on can cause noticeable dimming of lights due to drops in line voltage, that result.  This can be irritating, as well as hard on your electronic devices.  So, upgrade your electrical service if needed.  You’ll likely need a qualified electrician to perform this work for you.

Enough Circuit Spaces in Service Panel?

This will likely be a non issue if you’re upgrading your service panel / fuse box, as the new panel will likely have plenty of free slots for adding both 110 volt and 220 volt circuits. But if you’re not upgrading, you’ll need at least two free spaces in your power panel, since 220 volt circuits need two circuit breakers (one for each hot side of the line).

Plan the Thermostat Placement

Thermostat location affects overall comfort level in the heated room.  For the most comfort, plan to install the thermostat on an inside wall that does not get any direct updrafts from the baseboard heater you’re installing.  We put our t-stat on the opposite wall from the heater it controls.

Plan Baseboard Heater Placement

For the best results installing baseboard heaters, place the heater on the coldest wall in the room; an outside wall with windows on it works best.  Keep it low too.  Since heat rises, and since you want temperatures at floor level to be high enough that your feet stay warm, you’ll want the baseboard unit as low to the floor as you can get it, although in our case, we positioned the heater several inches above the carpeted floor, to simplify vacuuming and minimize damage to the heater from repeated vacuum cleaner collisions, by people rushing through their housecleaning chores.

Enough Insulation?

Electric heat can be quite expensive to operate, as it consumes much energy.  So you’ll probably want to make sure that you have plenty of insulation inside the walls, and particularly, above the ceiling in the target room, to make electric baseboard heat reasonably economical.  We used R-12 Styrofoam board insulation behind the walls and above the ceilings in the above pictured room.

Picture of the Honeywell RLV430A Programmable 5-2 line voltage thermostat, stock photo. Installing baseboard heaters.
Honeywell RLV430A programmable 5-2 line voltage thermostat, stock photo. Installing baseboard heaters.

Suggested Tools for Installing Baseboard Heaters

So, if you consider yourself handy, and have decided that you’re up for this task, then it’s time to assemble your tool kit.  You’ll probably need all of the following items:

Screwdrivers

Several sizes of straight and Philips head drivers, with medium length to long shafts will be used frequently here.

Rulers

A 100-foot ruler tape is best.  It’s flexible, and long enough for measuring whatever wire run lengths may be needed.

Multimeter

Helps when verifying correct voltage in your wiring.  It can also measure continuity as well as the actual resistance of the elements in the heaters.

Wire Stripper and Cutter

A hefty sized pair of diagonal pliers works well to cut through 12/2 electrical cable.  Also, they make strippers for this wire, that removes the outer jacket, which surrounds the whole bundle of three wires inside, but does not knick the internal insulation around each wire.

Circuit Tester

These are the little neon or LED lamps with two pigtail leads, that you insert into outlets, to determine if electricity is present.  You’ll want to use one of these often during any wiring project, to verify that the circuit under construction has no power.

Heavy Duty Electric Drill and Bits

You may need to drill holes in studs or walls, to route the wiring properly, and to mount the heater.

Fish Tape

If you need to route the wire behind walls, a twenty-five or fifty foot roll of highly flexible fish tape really helps.

Recommended Supplies for Installing Baseboard Heaters

The Electric Baseboard Heater Itself

Again, pick the largest heater that your electrical system, as well as your wallet, can support.  The hydronic baseboard heaters, we feel are best, as they’re the quietest, and have fewer hotspots that could burn someone if touched.

The Thermostat

We prefer models that switches off BOTH SIDES of the 220 volt line when turning off the heater.  These are safer, because when OFF, there’s absolutely NO voltage present in the heater.  However, with a single pole thermostat, the unswitched side of the line will still be connected to the heater, and thus, there will be 110 volts to ground present when the circuit is powered on.

Copper Electrical Cable

You’ll need standard 12/2 or 10/2 cable.  We advise against using anything smaller than #12, or anything larger than #10.  Further, if you must use #10 (such as necessary in longer runs, or on multiple heater circuits), get the stranded type.  Easier to bend, strip, and work with in general.

Circuit Breaker

Choose a breaker that’s the correct amperage.  General rule: If you’re wiring your circuit with #12 / 2 wire, then select a 20-amp model; if #10 / 2, choose a 30-amp size.   Consult the National Electrical Code handbook for the right size wires and breakers for your particular circumstances.

Wire Nuts and Electrical Tape

Needed to splice two sections of cable together inside junction boxes.  Never make connections outside an approved junction box.

Picture of the Honeywell 5-2 Thermostat RLV310A, Mounted and Operating.
Honeywell 5-2 thermostat RLV310A for electric baseboard heating, mounted and operating. Installing baseboard heaters.

Baseboard Heater Sizing Recommendations

Here in Pennsylvania, the winters can get pretty blustery and frigid.  In the space pictured above, a 1500-watt space heater worked reasonably well as long as the outside temperature did not fall below around 30 degrees.  However, when it did, and it does so quite often, that little space heater just could not keep up.  Even running at full speed and at highest heat settings, room temperature would fall, and bone-chilling coldness would ensue.

However, once we upgraded to a 2500 watt electric baseboard unit, the room never again got cold; even during week-long, below-zero spells.  On even the most frigid days, the duty cycle on the new heater was typically only fifty to sixty percent.  It’s best to choose a heater that has to run little more than half of the time, in order to maintain set point temperature. You don’t want to do all this work, only to find out that you undersized the heaters.

To avoid under-sizing, pick the largest baseboard heater that is practical for you in terms of purchase price as well as electrical capacity.  You should be able to afford it, and your mains electrical system should be able to supply enough current to the chosen heater(s).  Go as big as you can, is our advice.

Suggested Procedure for Baseboard Heater Installation

1. Figure Out the Heating Needs of the Target Room

Generally, pick the biggest baseboard heater that’s practical; especially if your house is only modestly insulated, or you live in very cold climates.  The price difference between the eight-foot 2500 watt models and the two footers really isn’t that great. So go for the gusto, and buy big.

2. Measure Wiring Length

Use the 100-foot ruler tape to simulate the actual planned run as closely as possible.  Measure in sections if a long run is anticipated.  Then, add five percent more to that total length, just to make sure you buy enough cable for the job, and to accommodate any unexpected additional lengths needed (such as routing around previously unseen beams, around pipes, or over attic crawlspaces).

3. Buy Baseboard Heater(s) and Supplies

Purchase the baseboard heater(s), thermostat, wire, and any tools you may need.  As you progress in this project, expect to make at least a few trips back to the home improvement center as you discover items needed that had not occurred to you before.

4. Run the Wiring

This is likely the most challenging step, because you may need to fish the wires behind walls and above ceilings.  If you have an unfinished basement and are installing the heaters on the first floor, wire routing should be fairly straight forward.  Or, if you’re installing on the second floor with an unfinished attic above it, again, fairly easy.  But if your basement or attic is finished, where you have no easy access to the interior of the walls above or below the target room, you may have to make holes in the walls at various places, to project the wiring where you need it.

5. Test the Wiring

Prior to tying this new run into your main circuit box, verify that there are no short circuits in any of the wires.  Shorts can occur if you hammered the wire fasteners too hard or over tightened the securing screws on the junction box wire holder clamps.

6. Install the Thermostat

Line voltage thermostats generally fit into a standard sized wall switch box.  The

7. Mount the Baseboard Heater on Wall

The best approach here is to drive several #10 or #12 wood screws through the heater body and into the studs behind the wall.  This is how we fastened ours.  Most baseboard heaters have many holes for this.  Make sure that the electrical wire pigtails line up with the heater’s built-in junction box; usually at one of the heater or the other; never in the middle though.

8. Make All Electrical Connections

Connect the now-mounted heater to electricity, following the heater’s included instructions.  If the heater sports a metal case or any exposed metal parts, then proper grounding is imperative, especially if installing in a bathroom or anywhere near sinks, water, or other grounded metal objects.

9. Test for Short or Open Circuits One Last Time

Now that the heating element is connected, you’ll get very low resistance readings when measuring across the 220 volt power line, between the heater and thermostat.  However, on the leg of wiring between the thermostat and the power source, you should read open-circuit values (no continuity or infinity resistance).

10. Set Baseboard Heater Thermostat to Lowest Temperature

Presumably, you’ll have to leave the room in which you just installed the new baseboard heater when you turn on the juice in the next step since, your breaker box .  But you’ll want to be there, when power is applied to the actual heater, to observe any problems.  So, to prevent the heater from coming on when you flip on its breaker, set the thermostat to the OFF position before applying power.

11. Turn On the Power

Next, head over / down to your house power panel, and energize the new heater circuit.  Keep your ears open when you throw the switch.  Listen for buzzing, spurts, sparks, or unusual humming, which may indicate a short circuit.  If this occurs, immediately turn off power and troubleshoot.  But if all is well (if you hear no troubling sounds, smell no smoke, or see no sparks), then proceed to the next step.

12. Test the New Baseboard Heating System

Return to the target area, and raise the new thermostat temperature to maximum.  This guarantees that power will be applied to the heater.  Again, listen, look, and smell for unusual activity.  Note that the heater may emit odors of burning dust and heating paint initially.  However, this will disappear after several hours of operation.  Check the heater.  It should begin producing heat within a minute or two at most.  If no heat, turn off power at the breaker and troubleshoot your wiring.  However, if proper heating is observed, then move on to setting up the thermostat.

13. Program the Thermostat

If you selected a programmable digital thermostat, set this up now, following its supplied instructions.  Otherwise, just set the temperature to that desired.

14. Clean Up After your Work

Put all your tools away, vacuum and dust the room with the new heater, as installation may have created dust.

15. Done!

Enjoy your new baseboard heater.

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References

  1. Revision History
  • 2019-05-25: Added key word targeting for ‘Installing Baseboard Heaters’, removed ad code scripts, and added more tags.
  • 2017-02-23: Originally published.