Live wires coming out of the wall
October 16, 2022 7:42 PM Subscribe
How do I know the right size of baseboard heater to buy?
When I bought this place I knew that there was a spot in my office that there was a baseboard heater that had failed and the previous owner had removed. There are wires still left, coming out of the wall. I was very surprised recently to discover that these wires are still live, when I tested them with an electricity checker. This was not a meter, it was just one of those pen-like things that beeps when electricity is present.
I would like to put in a new baseboard heater there. How do I figure out the amount of electricity coming through those wires so I can put in the right size?
There is no thermostat wired for this room, so I would need a heater with the thermostat built in.
When I bought this place I knew that there was a spot in my office that there was a baseboard heater that had failed and the previous owner had removed. There are wires still left, coming out of the wall. I was very surprised recently to discover that these wires are still live, when I tested them with an electricity checker. This was not a meter, it was just one of those pen-like things that beeps when electricity is present.
I would like to put in a new baseboard heater there. How do I figure out the amount of electricity coming through those wires so I can put in the right size?
There is no thermostat wired for this room, so I would need a heater with the thermostat built in.
Response by poster: i should have added: I'm in a remote rural area. There's no easy way to bring an electrician in.
posted by miles1972 at 8:24 PM on October 16, 2022
posted by miles1972 at 8:24 PM on October 16, 2022
How do I figure out the amount of electricity coming through those wires so I can put in the right size?
You’re going to have to figure out whether this circuit is 110V or 220V. (My electric baseboards are all on 220.) This will tell you what heaters will work given this supply. Some heaters work with both, but at 220 will run with half the current. When you locate the breaker, you should be able to tell which you’re getting, if you know what you’re looking for. You should be able to use Google images to tell the difference.
The amperage on the breaker will tell you the capacity for the whole circuit, so in theory you’d need to know what else is on the circuit. Outlets? (If 110V.) Other heaters? A clothes dryer? In reality, you’re probably ok replacing the heater with something that works for the room, probably similar to what was there before.
posted by supercres at 11:13 PM on October 16, 2022
You’re going to have to figure out whether this circuit is 110V or 220V. (My electric baseboards are all on 220.) This will tell you what heaters will work given this supply. Some heaters work with both, but at 220 will run with half the current. When you locate the breaker, you should be able to tell which you’re getting, if you know what you’re looking for. You should be able to use Google images to tell the difference.
The amperage on the breaker will tell you the capacity for the whole circuit, so in theory you’d need to know what else is on the circuit. Outlets? (If 110V.) Other heaters? A clothes dryer? In reality, you’re probably ok replacing the heater with something that works for the room, probably similar to what was there before.
posted by supercres at 11:13 PM on October 16, 2022
While, in theory, you'll want to check the circuit breaker, the size of the wire itself and for any other heaters or anything else on the same circuit, if you can see the size of the previous heater from the baseboards or the paint on the wall, it's fine to just replace the heater with one of the same size. The amount of electricity used per foot of baseboard heater is pretty standard.
posted by ssg at 11:16 PM on October 16, 2022 [1 favorite]
posted by ssg at 11:16 PM on October 16, 2022 [1 favorite]
You’re going to have to figure out whether this circuit is 110V or 220V.
A quick check to test if the circuit is 110 or 220 if all you have is that pen-type probe is to check if both wires show live, or just one does. With a standard socket you should see one pin live, the other (neutral) not.
This is not foolproof, just a quick check. Any doubt, get hold of a proper meter.
posted by Stoneshop at 2:31 AM on October 17, 2022
A quick check to test if the circuit is 110 or 220 if all you have is that pen-type probe is to check if both wires show live, or just one does. With a standard socket you should see one pin live, the other (neutral) not.
This is not foolproof, just a quick check. Any doubt, get hold of a proper meter.
posted by Stoneshop at 2:31 AM on October 17, 2022
If you can post a picture of the breaker feeding your baseboard circuit I can tell you if it's 240V or 120V.
Can you make out how long the previous baseboard was? Baseboards mostly are all the same wattage per foot so length directly translates to output.
Is your house all baseboard heat or is this baseboard supplemental for this area?
If the circuit is 240V and if you have other baseboards then best practice is would be to determine how much wattage is on the circuit feeding your office location. To do this turn all your baseboards off (use a piece of tape to indicate where they are currently set). Wait until they are cool. Switch the breaker to your office baseboard off. Turn all your baseboards on to maximum. Wait a couple minutes and then note which of the baseboards are not warm. Those are either on the off circuit or defective. You can now add up all the wattages on the name plates of those heaters. Take that number and divide by 240v to get amp draw. Compare to the number written on the handle of your breaker to determine how much amperage you can add.
If your baseboard feeder is 110V then it's a bit more complicated because they can be tapped off practically any of your regular circuits or may have a dedicated breaker.
If this is supplemental heat and the circuit is 240V it would be safe to just install a 500W baseboard; people rarely put heaters smaller than that on a 240V circuit.
All baseboards accept thermostats though with retail packaging it is easier to buy one with it built in.
posted by Mitheral at 5:17 AM on October 17, 2022
Can you make out how long the previous baseboard was? Baseboards mostly are all the same wattage per foot so length directly translates to output.
Is your house all baseboard heat or is this baseboard supplemental for this area?
If the circuit is 240V and if you have other baseboards then best practice is would be to determine how much wattage is on the circuit feeding your office location. To do this turn all your baseboards off (use a piece of tape to indicate where they are currently set). Wait until they are cool. Switch the breaker to your office baseboard off. Turn all your baseboards on to maximum. Wait a couple minutes and then note which of the baseboards are not warm. Those are either on the off circuit or defective. You can now add up all the wattages on the name plates of those heaters. Take that number and divide by 240v to get amp draw. Compare to the number written on the handle of your breaker to determine how much amperage you can add.
If your baseboard feeder is 110V then it's a bit more complicated because they can be tapped off practically any of your regular circuits or may have a dedicated breaker.
If this is supplemental heat and the circuit is 240V it would be safe to just install a 500W baseboard; people rarely put heaters smaller than that on a 240V circuit.
All baseboards accept thermostats though with retail packaging it is easier to buy one with it built in.
posted by Mitheral at 5:17 AM on October 17, 2022
Don't fix baseboard heaters; buy far more efficient room heaters.
I have a 200 year old house with baseboard heaters on the 2nd floor that don't work. had electricians come in to repair them and was told twice that they are ridiculously expensive to run and it is far less expensive to instead buy space heaters.
posted by yes I said yes I will Yes at 10:56 AM on October 17, 2022
I have a 200 year old house with baseboard heaters on the 2nd floor that don't work. had electricians come in to repair them and was told twice that they are ridiculously expensive to run and it is far less expensive to instead buy space heaters.
posted by yes I said yes I will Yes at 10:56 AM on October 17, 2022
Electric resistive heat is always 100% efficient regardless of whether it is a base board or radiant or space heater or quartz or whatever. Some of them can direct the heat to warm a specific object that might let one get away with not heating the space but otherwise they all cost the same to run.
posted by Mitheral at 1:21 PM on October 17, 2022
posted by Mitheral at 1:21 PM on October 17, 2022
Mitheral is right in that it takes the same number of watts to hit the same thermostat temperature regardless of the heater but electric heaters with large exposed surfaces can throw off enough IR radiation that you will feel toastier at a lower air temperature.
posted by goingonit at 2:17 PM on October 17, 2022
posted by goingonit at 2:17 PM on October 17, 2022
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But the capacity of the circuit should significantly exceed the draw of your baseboard heater at maximum. To size the heater, use a chart like this one.
Ultimately you will want an electrician to do the installation and they will do the above work for you in about half an hour for hardly any money, so I would just do that?
posted by goingonit at 7:50 PM on October 16, 2022 [2 favorites]