Portable electric room heater

[gary892]

I have been researching small electric room heaters for my dark room.

One important item I have noticed about all heaters I have looked at is they require to be plugged into an electrical outlet and NOT a power strip, extension cord or surge protector.

I do not have an available outlet in my darkroom but I do have an available outlet about 15 feet away.
I am thinking an industrial strength extension cord would be ok to use.



Thoughts?

Maybe suggestions on a different approach?

Thanks

Gary

[Willie]

Should work. We have them in a workshop as well as temporary use when sub zero outside in two bedrooms.
Have found the oil filled type, like old steam room heaters work well. No noise, no fan, one small light on the control that is easy to cover.

[Mark Sampson]

An extension cord meant for air-conditioners worked well for me in that application. Nowadays I have a tiny heater for the darkroom in winter; you don't need much in Tucson.
When I had a basement darkroom in Rochester I used one of the oil-radiator type. That needed some pre-heat time in the winter (ambient temp in the basement in winter was around 52F) but did the job for many years.

[neil poulsen]

I've used a ceramic type heater in my darkroom for decades . . . the same one. It's about a six inch cube. It has a fan, which is needed to project the heat into the center of the room. It sits conveniently on one corner of one shelf. Ceramic heaters are quite efficient.

[Drew Wiley]

The radiator convection style ones work best, are relatively safe (much safer than ceramic), and don't have glowing strips or coils, no blowing of dust either, but take a little while to fully warm things up. Anything high-wattage needs a decent heat-resistant extension cord 16 gauge or so, and not silly lamp wire. Ordinary power strips are rarely adequate and might even overheat and catch fire.

I can be absent-minded enough to walk away and sometimes forget a heater is on. With passive radiant heating, that might lead to an oversized utility bill, but not likely a fire. I'm not being paranoid. Earthquakes are fairly common here.

[jp]

Use a 12 or 14g super heavy duty extension cord and be fine. They don't recommend power strips or normal extension cords because they are made to varying quality and capacity and most are not up to it and most people don't think about Ohm's law and ampacity when plugging things in.

If you get one that different heat settings it will safer on the wiring and breakers if you don't run it at max power.

[Jody_S]

Ceramic heaters are quite efficient.

A common misconception that dates to the marketing campaign of the original cube ceramic heaters. Yes they were marginally more efficient than baseboard heaters, but that savings was 100% due to the fan circulating air better.

All resistive electric heaters are equally efficient. 1 Watt of electricity produces the exact same number of BTUs of heat regardless of the type of element used. Because any waste is dissipated in... heat. The gains in efficiency obtained from Convectair and similar brands of heater are twofold: by placing the heater away from the outside wall, you can lower the temperature of that outside wall and minimize heat loss through the wall, since heat loss is a function of the temperature differential between the two sides of the wall. 2nd, the electronic thermostats they use maintain a constant temperature for the heater, so instead of heating up to 140 degrees until the room warms up by 2 or 3 degrees and the conventional thermostat shuts off, the electronic thermostat outputs air from the heater at whatever temperature is necessary to keep the room at the set temperature. This again reduces the temperature of the wall it's placed on, and the ceiling, which reduces heat loss by lowering the differential. But it also maintains a constant air flow in the room, meaning there is less of a temperature differential between the floor and the ceiling. This lowered ceiling temperature again lessens the temperature differential which is the determining factor in heat loss through your walls and ceilings. Radiant heaters realize savings somewhat differently, by radiating heat directly to you instead of heating the air which then heats you (convection). But typical plug-in radiant heaters, like the oil-filled ones, heat the walls and ceiling equally as the occupants, negating that savings. The dish-type radiant heaters are more efficient than heating a large room, except they'll dry out your skin and give you a sunburn, plus of course you can't use one in a darkroom.

To get something more efficient, you need to get away from resistive heaters (like all plug-in space heaters) and go to heat pumps or whatever other technologies are out there now. Radiant floor heating is also very good, with the added benefit that it can keep your house from freezing for several days in the event of a power failure. It will heat your floor to whatever temp it's set at, and nothing in that room can then be raised above that temperature by the heating system. So a 72 degree floor means a 72 degree ceiling, compared to a sporadically 140 degree ceiling with baseboard heaters and conventional thermostats. In 0 degree weather, that's nearly a 50% drop in heat loss through your ceiling.

[Dugan]

The problem with using extension cords is that they themselves can become heating elements....Ohm's Law, as stated above.

[Jody_S]

The problem with using extension cords is that they themselves can become heating elements....Ohm's Law, as stated above.

The weak points are the two ends of the extension cord, the connections often heat to the point of making the plastic malleable, and of course couches. Many a house fire has been started by a couch pinching an electric cord. I don't worry too much about it if the heater is only in use while I'm in the room, and I have working smoke alarms.

[domaz]

One more immediate concern with electric heaters might be if it will trip your breaker when you start using other appliances in your darkroom. A space heater can easily draw 12 amps, unless your darkroom is all LED and very efficient, something else will likely draw more than 3 amps causing a typical 15 amp breaker to trip. There are tiny space heaters that only draw a couple hundred watts, they don't much but in a small room it's enough to take the chill off.

[Drew Wiley]

Heck, just plan on a little mounting first. A drymount press will heat things up fast enough! One more reason to have plenty of juice going into the darkroom. Mine even has its own subpanel, with both 110 and 220 voltage. But I never mount anything in the same room as I develop prints. No "dry side" versus "wet side" for me; completely different rooms instead! Even separate rooms for the enlargers and film work. Don't need a bunch of corrosion or mildew!

[LabRat]

Another danger point is the outlet itself... Old outlet contacts oxidize, get slightly burnt, become resistive and can become a heating element itself and can get dangerously hot with normal to higher current devices plugged into them... Sometimes defective even new ones can generate heat/sparks...

A good weekend project would be to plan on replacing all outlets in your space with new, with GFCI in wet locations and good grounded in other places, and get one of those outlet tester plug-ins to check for a good ground and proper phasing...

New outlets are only around a buck a piece, and good insurance from electrical issues...

Steve K

[LabRat]

Oh, and another tip with in-room heaters is that they can dry the air severely in use, so getting a humidifier from your drug store will help keep static and dust down and is easier on your sinuses and dry eyes...

Short of that, you can also hang a wet, non dripping towel in the room to provide some humidity as it dries out...

Really helps when the air is so dry that your fingers act like 10 spark plugs and your roll film starts curling up like a long straw...

Steve K

[jp]

Another danger point is the outlet itself... Old outlet contacts oxidize, get slightly burnt, become resistive and can become a heating element itself and can get dangerously hot with normal to higher current devices plugged into them... Sometimes defective even new ones can generate heat/sparks...

A good weekend project would be to plan on replacing all outlets in your space with new, with GFCI in wet locations and good grounded in other places, and get one of those outlet tester plug-ins to check for a good ground and proper phasing...

New outlets are only around a buck a piece, and good insurance from electrical issues...

Steve K

According to youtube and it's worth considering.. The cheapest outlets are junk and you get way better ruggedness and reliability spending $5 instead for an outlet which is still very reasonable.

[John Layton]

I also like my oil filled radiator/heater. No dust blowing around, on wheels so I can move it around depending upon what else I'm doing in the darkroom - and can later position it for maximum (convective current) effectiveness while I'm not present.

As mentioned above...just be careful of current draw as this may affect other important accessories which may depend on the same circuit.

When I designed and built my current darkroom, I made sure that my enlarger bench had its own isolated electrical circuit...keeping any relatively "high draw" accessories like the room heater and film dryer from adversely affecting enlarger lamp output. Even so...I'll still turn off the room heater while I'm making an (enlarger) exposure - just to be sure!

[Daniel Stone]

Firstly, the one you likely already have, and might not have considered: a sweater or hoodie. Costs nothing to add, can easily be stored away in warmer months, and doesn't impact your electric bill until you need to launder it :P
Appropriately sized base layers can help too, and those can be used while out shooting in cooler weather as well :)
I've used the "dish" heaters sold at many big box retailers during winter months. I don't leave them on for long, just enough to warm a space to 65-70F and then turn it off. You can set them up on a timer as well, some even have this feature straight from the factory now.

-Dan

[Drew Wiley]

Humidifiers?.... Interesting thought, but sure not here on our coast! Just the opposite. One has to periodically check electrical contacts and wiring for symptoms of damp salt air corrosion. Good reliable darkroom outlets are more likely to cost you around twenty bucks apiece, preferably from a real pro electrical supply house and not some Cheapo Depot kind of outlet. And you want higher capacity 20A ones than just room lighting requires. Any power strips should be industrial grade with a thick cord, like used for serious power tools and not just little office and computer toys. You get what you pay for.

Any new darkroom should be wired to at least the code standards of a kitchen, because both involve high-wattage "appliances".

[LabRat]

During a particularly dry Santa Ana wind spell (with RH about 2%), I had a large printing project, but felt like Edward Scissorhands when getting severe shocks touching anything grounded seeing/feeling an arc, and the first few prints had the "mark of the beast" static marks printed into the borders, so had to do something fast!!! Grabbed a bucket and mop and slathered water all over the floors (which dried in 15 minutes) to hold down static, then re-applied the entire long printing session...

Shocking...

Steve K

[Tin Can]

1/2 my location year is very humid

Winter I run 5 to 10 gallons a day in my DR humidifier, I even have a dedicated hose for it as the humidifier is under my DR sink

As my furnace inlet is 10 ft away I get full small house Humidification

I also treat water for this usage

[Maris Rusis]

I live in a warm climate but the darkroom needs a bit of heat for two months a year. After fussing with a fan heater, bar heater, and an oil filled radiant I finally snapped, bit the financial bullet, and had the darkroom properly wired up with 6 power outlets (need 'em all). Then I had the smallest reverse cycle air-conditioner installed. In reverse it's the cheapest source of heat. In cool mode it's bliss in summer.
I figure I'm going to spend several hundred hours in there so it better be nice.

[Drew Wiley]

Steve - Normally October is the driest hottest month of the year here on the Bay. With the big industrial air cleaner running, I'd first wipe down the Formica countertop with a clean microfiber cloth to humidify things a bit before handling unexposed film, or I might get a little lighting-like static mark using a registration punch. But this year ... Gosh, had six inches of rain over about 18 hrs just two days ago. It's possible to buy actual anti-static Formica soaked in silver nitrate, but it's damn expensive. There are also grounded gloves available from cleanroom houses that cater to the local electronics tech industry. I have air ionizers and an antistatic air gun on hand if needed, but rarely bother with them.

I don't like the idea of humidifiers in the film room or around my high-end enlargers and lenses. There are simpler solutions, and by doing certain tasks just certain months helps quite a bit. Normally I'd be doing a lot of drymounting in Nov and Dec while things cool down but aren't very wet yet, but this year is tuning out odd. But our drought needs all the rain we can get.

[JMO]

Firstly, the one you likely already have, and might not have considered: a sweater or hoodie. Costs nothing to add, can easily be stored away in warmer months, and doesn't impact your electric bill until you need to launder it :P
Appropriately sized base layers can help too, and those can be used while out shooting in cooler weather as well :)
I've used the "dish" heaters sold at many big box retailers during winter months. I don't leave them on for long, just enough to warm a space to 65-70F and then turn it off. You can set them up on a timer as well, some even have this feature straight from the factory now.

Dan, I’m with you about keeping oneself warm in chilly darkrooms - clothing layers. The other important thing to keep at temperature when making prints are the chemical trays. For this, some of us in the Upper Midwest rely on pig warmer heating pads (which I have discussed in other threads). It may be 55-60F in my basement darkroom during most of the year, but my trays are always at 21C.

[LabRat]

Steve - Normally October is the driest hottest month of the year here on the Bay. With the big industrial air cleaner running, I'd first wipe down the Formica countertop with a clean microfiber cloth to humidify things a bit before handling unexposed film, or I might get a little lighting-like static mark using a registration punch. But this year ... Gosh, had six inches of rain over about 18 hrs just two days ago. It's possible to buy actual anti-static Formica soaked in silver nitrate, but it's damn expensive. There are also grounded gloves available from cleanroom houses that cater to the local electronics tech industry. I have air ionizers and an antistatic air gun on hand if needed, but rarely bother with them.

I don't like the idea of humidifiers in the film room or around my high-end enlargers and lenses. There are simpler solutions, and by doing certain tasks just certain months helps quite a bit. Normally I'd be doing a lot of drymounting in Nov and Dec while things cool down but aren't very wet yet, but this year is tuning out odd. But our drought needs all the rain we can get.

Yea, we missed the weather bullet in SoCal yesterday with light to medium rain... Concern about the rain up north, so hoping for the best...

Normally have 30 to 70% RH, but have had 1-2% humidity spells where leaving a roll film strip on the counter turns it into a drinking straw and fingers seem to spot weld to everything... I remember growing up in the east when winter dryness + heating was like a personal lightning generator, at least up in the bay + coast the "killer fog" keeps the static at bay...

Don't usually humidify the lab, but have taken measures when humidity was really low... Also have bench surplus static control generators that help...

Usually have a humidifier in the bedroom for dry winter nights to keep the sinuses from drying out, but understand one might need a dehumidifier in the lab with a lot of sea air moving around...

Steve K

[Tin Can]

Humidity slows dust

I have a SS cabinet for lenses in shooting studio

[Drew Wiley]

Well ... rain. Just two days after it here, the hills have gone from totally brown to large areas of green everywhere. Amazing how fast the change happens. I hate hot humidity. It's rare here.