Space Heater Thermostat Temp-based or just Duty Cycle

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lawman3966
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Space Heater Thermostat Temp-based or just Duty Cycle

Post by lawman3966 »

Appealing to the techies out there to resolve a dispute.

Our home in WA uses only electric space heaters for heat. One resident is attempting to map a combination of space heater thermostat settings to the resulting room temperature, in order to come up with thermostat settings we can stick to.

My impression is that the space heater adjustment knob is not a real thermostat in that there is no mechanism for "informing" the space heater what the room temperature is, and thus no mechanism for turning the heating elements on and off based on the room temperature. (By room temperature, I mean the temperature of the room in general, not a region in the immediate vicinity of the heater which will always be much hotter than the room is).

My feeling is that any attempt to determine a fixed mapping of this pseudo thermostat setting to room temperature will fail. Specifically, it seems likely that when the outside temperature rises, and the sun comes up, the room temperature will rise even without anyone changing the thermostat setting.

Can anyone explain precisely what the space heater thermo adjustment knob does? It seems clear that it's not a normal full-fledged room-temperature based thermostat. I'm also not sure that it's really a pure duty cycle setting: that is, where "1" means it's on 10% of the time, "5" means it's on 50% of the time, etc.

All informed input appreciated.
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telemark
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Re: Space Heater Thermostat Temp-based or just Duty Cycle

Post by telemark »

It depends on the model. I have a Vornado that has a real thermostat, and some others where the dial just adjusts the power output. Even with a real thermostat, the sensor is going to be part of the heating unit and thus located in the warmest part of the room when the heater is running.
iamlucky13
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Re: Space Heater Thermostat Temp-based or just Duty Cycle

Post by iamlucky13 »

All the space heaters I've seen have simple thermostatic knobs, or in some newer cases, electronic thermostats. Even if the unit is unplugged and has no way of monitoring duty cycle, you'll hear the former click as you turn the knob back and forth.

The knobs are very approximate and probably vary from unit to unit, and certainly from one brand to another. They also are susceptible to heat conducted to the built-in thermostat, which makes the resulting air temperature inconsistent as the outside temperature changes.

Also, if I remember right in Washington state, if a dwelling does not have a permanently wired or plumbed primary heating source, it is out of code. I don't remember where at the moment to check for confirmation on that. I suppose whether that is a deficiency you'd want to raise a fuss about might depend on whether you're putting up with using space heaters because of a really good rental deal that you don't want to ruin.
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lawman3966
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Re: Space Heater Thermostat Temp-based or just Duty Cycle

Post by lawman3966 »

iamlucky13 wrote: Mon Dec 11, 2017 11:55 pm Also, if I remember right in Washington state, if a dwelling does not have a permanently wired or plumbed primary heating source, it is out of code. I don't remember where at the moment to check for confirmation on that. I suppose whether that is a deficiency you'd want to raise a fuss about might depend on whether you're putting up with using space heaters because of a really good rental deal that you don't want to ruin.
If you have a link to a site requiring that buildings in WA state require a permanently wired or plumbed primary heating source, I would love to see it. It would be valuable information with which to press my position with the landlord. I've looked for this briefly so far, but haven't found it.

Separately, I have looked for rules from either Washington state or from the city of Tacoma requiring a minimum temperature be maintained, but have not been able to locate any such rules so far.
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lawman3966
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Re: Space Heater Thermostat Temp-based or just Duty Cycle

Post by lawman3966 »

iamlucky13 wrote: Mon Dec 11, 2017 11:55 pm
Also, if I remember right in Washington state, if a dwelling does not have a permanently wired or plumbed primary heating source, it is out of code. I don't remember where at the moment to check for confirmation on that. I suppose whether that is a deficiency you'd want to raise a fuss about might depend on whether you're putting up with using space heaters because of a really good rental deal that you don't want to ruin.
Ok, one correction is needed. Since I was principally asking about the adjustment knobs, I jumped the gun a little in connection with the temporary/permanent wiring status of the heaters. There is a mix of permanently wired electric heaters and portable space heaters. I still think that Washington State R303.9 is being violated since only a few rooms have the fixed heaters and don't appear to have ever been sufficient to heat the house to 68 degrees, as required by R303.9.
iamlucky13
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Re: Space Heater Thermostat Temp-based or just Duty Cycle

Post by iamlucky13 »

A complication is matters that fall under building code can generally be grandfathered in. I know remodeling work requires anything you substantially alter to be brought up to code, but that's not the question here.

What I don't know is what parts, if any, of the building code might not be allowed to be grandfathered in. I thought permanently installed heating systems were one, but I can't find a clearly stated requirement at the moment. These may be covered not in the residential code, but instead by tenant laws at the state, county, or city level. Washington's landlord duties are here, which includes a requirement not entirely defined to first of all, maintain the heating system that was there when you moved in, and secondly to provide, "facilities adequate to supply heat and water and hot water as reasonably required by the tenant."
https://app.leg.wa.gov/rcw/default.aspx?cite=59.18.060

Other parts of that chapter cover repair obligations and complaints.

This author also points to a municipal requirement for Seattle specifically:
https://www.warealtor.org/resources/REm ... inter-2017

Looking at Tacoma code specifically, this document has a 70 degree requirement and does not allow it to be met by space heaters on page 30 here, but from a quick read of the section, I think it allows grandfathering.
http://cms.cityoftacoma.org/cityclerk/F ... ldings.PDF

This should be read as the ability of the heating system to provide enough heat to reach those temperatures, not necessarily of the controls to maintain that temperature accurately.
Last edited by iamlucky13 on Tue Dec 12, 2017 4:09 am, edited 1 time in total.
iamlucky13
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Re: Space Heater Thermostat Temp-based or just Duty Cycle

Post by iamlucky13 »

One more thought that came up is to check your rental contract just in case it forbids space heaters. It's a long shot, but using a contract from a template with common conditions might have effectively written the landlord into a corner.
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just frank
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Re: Space Heater Thermostat Temp-based or just Duty Cycle

Post by just frank »

lawman3966 wrote: Tue Dec 12, 2017 1:08 am
iamlucky13 wrote: Mon Dec 11, 2017 11:55 pm Also, if I remember right in Washington state, if a dwelling does not have a permanently wired or plumbed primary heating source, it is out of code. I don't remember where at the moment to check for confirmation on that. I suppose whether that is a deficiency you'd want to raise a fuss about might depend on whether you're putting up with using space heaters because of a really good rental deal that you don't want to ruin.
If you have a link to a site requiring that buildings in WA state require a permanently wired or plumbed primary heating source, I would love to see it. It would be valuable information with which to press my position with the landlord. I've looked for this briefly so far, but haven't found it.

Separately, I have looked for rules from either Washington state or from the city of Tacoma requiring a minimum temperature be maintained, but have not been able to locate any such rules so far.
In my case years ago, the lease contained appropriate language for supplying heat and water, etc. Not that the landlord abided by that. :annoyed
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lawman3966
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Re: Space Heater Thermostat Temp-based or just Duty Cycle

Post by lawman3966 »

iamlucky13 wrote: Tue Dec 12, 2017 4:02 am
Looking at Tacoma code specifically, this document has a 70 degree requirement and does not allow it to be met by space heaters on page 30 here, but from a quick read of the section, I think it allows grandfathering.
http://cms.cityoftacoma.org/cityclerk/F ... ldings.PDF

This should be read as the ability of the heating system to provide enough heat to reach those temperatures, not necessarily of the controls to maintain that temperature accurately.
Thanks very much for the link to the Tacoma code. This will come in handy.
You write that the code pertains to the ability of the heating system to reach those temperatures, not of the controls to maintain that temperature. In our case, the LL uses mostly portable space heaters for the main heat of the home, and much of the time, all of them are off. With our recent weather, the temperature on the main floor has fallen to 58 degrees at night. From what you write, it's not clear whether the code prohibits that or not.

This house was built around 1910, but went through a remodel in the late 1980s or so.

Thanks again for the info.
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