Reworking electric heat in apt.s

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cptviggi

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I have a situation where a landlord wants to split up the heat in his 10 unit building. Presently, they have 1 furnace to supply the whole place with electric heat in each apt. so the tenants can "take the edge off" if they want.
He wants to know what it will take to get the electric heat up to a point to where he can get rid of the furnace and have the tenents pay for their own heat on their electric bills.
Each room in each apt. has a small baseboard heater(not all working) with individual on/off knobs. Apts range from 375 sq. ft to 525 sq.ft, 4 and 5 rooms respectively.
I'm not quite sure how to size the heaters to the correct size or as how to control them but this is what I was thinking:
Have a thermostat control a small contactor in the basement to turn on and off the neccesary circuits, or have each room individually controlled with a stat on the wall.
Also, we have a bunch of mc 12-4/12-2( as in bk,r,bl,w,g, orange, and white with orange stripe all in one mc) left over from a job and I was hoping I could use that. Maybe i'm overthinking, but does anybody see any problems running 4 linear loads down 1 mc? Thanks again...
Is it common to have electric heat in apt.s anyway, or is this guy just being cheap, not wanting to pay the heat bills?
 
I am not sure where you live but here in NC we use about 7 watts/ sq. ft in a standard insulated home. That is usually a very safe number.
 
The IECC would normally require that the building be insulated to a value required by your "zone" before you can change to electric heat in that building. I bump into this request at least 15-20 times a year. Check with both your electrical inspector and your building/energy inspector before you commit to any of this type of work. That's also a substantial amount of new load for the building, so the POCO will want to know this as well. May even require a service upgrade.

If the building has hydronic heat already, a plumber can often seperate out the pipework a bit and install seperate furnaces for about what you could put in electric heat for. Not trying to talk you out of it, but just food for thought.

As far as rules of thumb go, I use 1 watt per cubic foot here in central PA to size electric heat.
 
wtf...

wtf...

I hooked up some heaters in apt. #1 and turn them on to check them and they became super hot to touch. I could barely keep my hand on them once they heated up, but I can tell you I didn't want to.
I called up a hvac friend who has one of those thermo guns to measure the temp. of things it's focused on and it came up with a reading of 180 degrees give or take.
WTF?
This is turning in to a job from hell. These heaters have a thermal overload to prevent from overheating, so either I have bad heaters or they are supposed to run this hot?
I can't believe they are supposed to run this ho,t are they?
I wouldn't have anything to do with running a heater in 80 degree weather with no cold air to cool it, would it?
 
Have you ever hooked up an electric baseboard heater before? :grin: Yes, they get super hot. That's why it's important to keep furniture and draperies away from them.
 
i used to do some of those things in nursing homes and apts, i cant remember the formula but 10 watts per sq ft comes to mind. contact the manufactuer and they could give you a fomula for your area and insulation value.
and yes they get HOT! for that reason i wont install one in a home with little kids, imo they are a fire hazard.
 
Honestly..

Honestly..

I don't think I've wired Electric heaters working for myself before.

The last time I remember doing them was when I was working for someone else and honestly, I don't think I cared about things as much as I do now, with my name on it. I hate to admit that.
 
cptviggi said:
I hooked up some heaters in apt. #1 and turn them on to check them and they became super hot to touch. I could barely keep my hand on them once they heated up, but I can tell you I didn't want to.
I called up a hvac friend who has one of those thermo guns to measure the temp. of things it's focused on and it came up with a reading of 180 degrees give or take.
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There are 120v heaters and 240v heaters; make sure you're matching supply voltage and heater voltage.

Electric heaters are designed to run hotter than the desired temperature. Thermostats cycle them on and off; they don't control the element temperature. Your electric oven works the same way.
 
Reworking electric heat in apts

Reworking electric heat in apts

mattsilkwood said:
i used to do some of those things in nursing homes and apts, i cant remember the formula but 10 watts per sq ft comes to mind. contact the manufactuer and they could give you a fomula for your area and insulation value.
and yes they get HOT! for that reason i wont install one in a home with little kids, imo they are a fire hazard.
Click to expand...

As usual you have gotten good advice. Remember electric heaters are safe when wired properly. They have been approved by UL. Again make sure you are using the proper voltage and wiring the thermostat correctly. Thermostats come single pole or double pole. Single pole just breaks the voltage from 220 V to 110 V to cool it down. Double pole thermostats break all voltage. I prefer double pole thermostats. Semper Fi
 
Brady Electric said:
Thermostats come single pole or double pole. Single pole just breaks the voltage from 220 V to 110 V to cool it down. Double pole thermostats break all voltage. I prefer double pole thermostats. Semper Fi
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Actually, single-pole and double-pole T-stats both turn the element on or off. There is no way to merely reduce the voltage supplied; that would require a 3-wire supply.

The difference is that double-pole T-stats open both lines when fully off, whereas single-pole T-stats open only one line. In both cases, no current flows.
 
Brady Electric said:
Double pole thermostats break all voltage. I prefer double pole thermostats.
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I don't think it matters. If you've ever had to change the contactor on a central ac unit, or troubleshoot one, chances are it's only a single pole contactor. Either way, as Larry said, if you open one "hot" of 240 volt circuit, it's an open circuit and the unit does not operate.
 
peter d said:
I don't think it matters. If you've ever had to change the contactor on a central ac unit, or troubleshoot one, chances are it's only a single pole contactor. Either way, as Larry said, if you open one "hot" of 240 volt circuit, it's an open circuit and the unit does not operate.
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The only time it matters is if your using the tstat to meet 424.19, then your tstat would have to be marked with an OFF position...
 
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