Two of the guest bedrooms in my house are under the same circuit breaker trip switch. I just found out that I can't have a 1500W room heater plugged inside each of those bedrooms at the same time, as the circuit breaker trips when I do that. This is inconvenient as we use room heaters at night in the bedrooms we use to save on electric bill. Is there a way I can easily & safely "adjust" the circuit breaker so raise the "trip threshold" just enough so that it does not trip with the 2 heaters on? Or is this a job that will require rewiring the 2 rooms?

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    If your breaker says 15, you have a 1440W budget. If it says 20, you have a 1920W budget. For instance twoheaters at their lower 700W setting will do fine. Commented Jan 21, 2018 at 0:24
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    Put shrink plastic on the windows. And avoid portable electric heaters like the plague -- they're expensive and a big fire hazard.
    – Hot Licks
    Commented Jan 21, 2018 at 2:03
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    @Harper are we sure about OP's mains voltage? there is no location tag or mention of country (and btw. what does the home-theater tag mean here)?
    – dlatikay
    Commented Jan 21, 2018 at 13:11
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    Do not change the breaker without changing the wire. You need 12 or 10 gauge wire, otherwise the wires will probably start on fire. You need 1 new circuit just for the heater then you only need to re wire 1 room.
    – cybernard
    Commented Jan 21, 2018 at 18:20
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    @dlatikay a rest-of-the-world 13A or 16A circuit could carry two 1500W heaters. Commented Jan 21, 2018 at 19:06

5 Answers 5


Conventional residential circuit breakers are safety devices that are not subject to adjustment. They are sized based on what the wires to the outlets can safely handle.

As you surmised, if you want to draw more power to that area, you need more wiring.

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    As a side note, there are circuit breakers that can be adjusted. They're significantly larger than those typically used residentially, though, and cost more than everything in your panel put together. Commented Jan 21, 2018 at 6:49
  • @SomeoneSomewhere Noted. I made and edit . That's the problem with making an absolute statement.
    – bib
    Commented Jan 21, 2018 at 16:18
  • Very good simple answer, although I would edit to clarify: "They are sized based on what the wires and all interconnects can safely handle", as often trouble starts with arcing at the outlets or within rated plugs themselves. I would also add a health warning commensurate with the apparent lack of common sense of the original question such as "always check the allowed power rating of electrical equipment you plug in, as this is how house fires can start" or somesuch. As breakers are thermal devices, it's often possible to draw more power on a continuous basis than they are rated for.
    – hazymat
    Commented Jan 21, 2018 at 19:22

This is inconvenient as we use room heaters at night in the bedrooms we use to save on electric bill.

Electric resistive heat is the most expensive way to heat a home. If your central heating method is electric resistive heat then using unit heaters will not save you anything. KWh's are the same whether they come from the central heat or the unit heaters. If your central heat is natural gas, propane, or heating oil, then you are wasting your money with electric heaters since the other methods are much cheaper.

As bib points out, standard home breakers are not adjustable and the only way to increase capacity to that area of the home is to add at least one more circuit.

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    What we're doing is using electric heaters in the 2 bedrooms we sleep in, instead of heating the entire house. I believe natural gas (+ fan) for the entire house is more expensive than electric heaters for a small part of the house. Commented Jan 21, 2018 at 0:50
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    True, that just depends on the size of the house and how warm you like to keep it in you bedrooms. Most people sleep better in cooler temperatures. Natural gas is dirt cheap right now.
    – ArchonOSX
    Commented Jan 21, 2018 at 1:04
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    @FijoyVadakkumpadan - Any decent forced air heat installation has adjustable registers. Close most of the registers other than in the bedrooms and whatever room is closest to the thermostat.
    – Hot Licks
    Commented Jan 21, 2018 at 2:05
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    @FijoyVadakkumpadan - A better thermostat system would probably be the best option in the long run.
    – Fake Name
    Commented Jan 21, 2018 at 7:36
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    @stannius - You shouldn't completely close all the registers, but closing 1/2 or even 2/3rds of them should cause no problem (other than uneven temps, which the OP already has). The fan will not "wear out" due to this.
    – Hot Licks
    Commented Jan 21, 2018 at 19:35

If you can't increase the wattage available in the rooms (which requires running more circuits as others explain), apply the heat more tactically. Heated blankets or mattress pads can provide more comfort for less wattage than room heaters.


You could always run an extension cord to another room that is on another group/breaker. But that does not solve your real problem either: that you can't heat your house the way you want to.

You did not mention what type your regular heating is. If it affects your electricity bill then it is presumably a heat pump, which has a far greater efficiency (COP) than a resistive heater. The only problem is that it heats up the rest of the house too. Some of that is desired, you don't want to have breakfast in an iglo. But, does it work with air or circulating water ? Because if it is water then there is a nicer solution.

I have a Honeywell Evohome system where the temperature in each room is regulated individually, even if it is the only room in the house that requests heat. This is an extreme form of zoning. There exist also heating systems with only 2 zones, where you can control 2 floors separately, with 2 thermostats. I have (almost) as many thermostats as there are rooms. If any room requests heat then the central controller turns on the gas furnace but keeps the radiator valves for the other rooms closed. I'm not saying that I am saving any gas, but the comfort has increased tremendously, especially in the bathroom. It is warm long before the room where we have our breakfast.

And yes, I installed it myself (this is DIY). Not recommended by Honeywell, but I used to be handy. It isn't too hard if you have hydraulic and computer skills. It's much more expensive than installing an extra breaker, though.

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    1500 watts is at or above the limit for most extension cords, particularly for a continuous load such as an electric heater.
    – Mark
    Commented Jan 21, 2018 at 7:59
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    true, but if you want to go this route you can find suitable extension cords. Look for 15 amp / 12Ga cords. You want one of just the length you need, don't get a super long one. The usual rules for extension cords apply, don't run under carpet, etc.
    – agentp
    Commented Jan 21, 2018 at 16:36

The wiring could be sufficient to allow for higher current. it is technically possible, and allowed, to fit a circuit with a breaker with a lower treshold current than that the wiring can take.

But before you think of replacing the breaker with one >15A, you would have to look at the wiring - depending on your location and legislation, have a certified professional do that.
Under no circumstances increase a fusing current beyond the current the circuit protected by it can take.

If the two rooms do have separate circuits that happen to be wired to the same breaker inside the panel, separation and a second breaker could solve the problem as long as the overall current capacity of the panel (one of its phases) is not exceeded.

  • quite possibly more work to make that determination than to just run a new circuit..
    – agentp
    Commented Jan 21, 2018 at 16:39
  • Checking for #12 wire is about a 5 minute task. It would be quite unusual for someone to protect #12 wire with a 15 amp breaker since you are losing capacity. However, it is possible and worth a look.
    – ArchonOSX
    Commented Jan 21, 2018 at 20:24

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