Infrared heating safe for guitars, or not?

[Christian Miller]

From what I saw, using IR heaters exclusively does require proper insulation. Didn't get that at first, but typing this post it occurs to me that they'll heat the ambient air last. Meaning that until that moment, any air movement will undo the cozy feeling pretty easily because it'll be "cold" air. Plus you'll get a gradient that's not unlike sittng in front of a fire as the only heat source: one side can cook while the other side can feel freezing. Good thing those electric IR heaters don't suck in cold air

That's what I would have thought.... It would be interesting to hear how it feels.

In terms of 'slowness' obviously propagation of IR is at the speed of light as for a lightbulb, but the rate of energy transfer is slower than for convection. Also surface area and temperature gradient is important, hence the flat panels that get very hot, I guess.

[RJVB]

That's what I would have thought.... It would be interesting to hear how it feels.

I've been toying with the idea of getting one of the mobile smaller panels as an add-on heater for in my study because it's annoyingly hard to heat. They're a bit too expensive though and winter so ... absent that I have even hardly had to turn on my heated vest... Looks like it won't be this year that I'll find out if the IR heating hype is justified.
(But they're available on A'zon, so a dive in the evaluations could tell more.)

but the rate of energy transfer is slower than for convection.

Why? Air is notably bad at conducting heat, as was pointed out to me on here a few months back when discussing my brilliant idea of canning food in the oven

Funny that I cannot recall reading any warnings that these panes get very hot, and that seems to be contradicted by the fact that they can be wall-mounted without the kind of heat protection behind them that a traditional stove requires.
I'm particularly intrigued by the models that are meant to be ceiling-mounted btw. That must really be comfy for ageing necks and shoulders

[Christian Miller]

I've been toying with the idea of getting one of the mobile smaller panels as an add-on heater for in my study because it's annoyingly hard to heat. They're a bit too expensive though and winter so ... absent that I have even hardly had to turn on my heated vest... Looks like it won't be this year that I'll find out if the IR heating hype is justified.
(But they're available on A'zon, so a dive in the evaluations could tell more.)



Why? Air is notably bad at conducting heat, as was pointed out to me on here a few months back when discussing my brilliant idea of canning food in the oven

Funny that I cannot recall reading any warnings that these panes get very hot, and that seems to be contradicted by the fact that they can be wall-mounted without the kind of heat protection behind them that a traditional stove requires.
I'm particularly intrigued by the models that are meant to be ceiling-mounted btw. That must really be comfy for ageing necks and shoulders

Air is a good thermal insulator but heat can be effectively transferred away by atmospheric convection. Which is how domestic ‘radiators’ work, and also ‘radiators’ in car engines etc. These things are obviously designed to encourage convection but some will occur naturally anyway.

(It’s also why spacecraft need massive thermal radiator panels to ensure the crew aren’t cooked - no convection in space, see also vacuum flasks.)

The IR panel’s tendency to get hot is mentioned on the Hershel site.


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[supersoul]

My absolute favorite portable heater was a Presto Heat Dish. It looked like a little radar dish, which would transmit a beam of heat from the glowing element in the center. That was infrared heat.
The place I was living at the time was quite cold, bad insulation and very drafty. Any heat would immediately be pushed out by cold air from the outside. The Heat Dish was awesome, because I would just point it at wherever I was sitting and I would be toasty warm. Move out of the beam and I'd be cold. It was like a laser beam of heat.
The position of the cat on the box cover is fairly accurate. Mine would sit on my lap in such a way as to absorb the heat beam and block it from reaching me. If it were my cat in the photo, he would be sitting on her right shoulder, for maximum heat absorption.
I don't know how a infrared panel would work. It would probably spread the heat out more than a dish, but the principle is the same. It delivers its heat in a direct line of sight. I don't think I would worry about it more than any other heat source.

[Christian Miller]

My absolute favorite portable heater was a Presto Heat Dish. It looked like a little radar dish, which would transmit a beam of heat from the glowing element in the center. That was infrared heat.
The place I was living at the time was quite cold, bad insulation and very drafty. Any heat would immediately be pushed out by cold air from the outside. The Heat Dish was awesome, because I would just point it at wherever I was sitting and I would be toasty warm. Move out of the beam and I'd be cold. It was like a laser beam of heat.
The position of the cat on the box cover is fairly accurate. Mine would sit on my lap in such a way as to absorb the heat beam and block it from reaching me. If it were my cat in the photo, he would be sitting on her right shoulder, for maximum heat absorption.
I don't know how a infrared panel would work. It would probably spread the heat out more than a dish, but the principle is the same. It delivers its heat in a direct line of sight. I don't think I would worry about it more than any other heat source.

Yeah that would work on the same principle. It would be a heat lamp with a parabolic reflector, so much more directional than the room heaters Rob is talking about and more useful over a longer distance.

A parabolic reflector takes a the divergent beams from an (approx) point source at the focus and reflects them into parallel lines, so a tight beam. It’s like a the James Webb Space telescope, or as you say, satellite dish in reverse.

Otoh you wouldn’t expect the large flat panel heater to drop off with the inverse square law as with a naked bulb. The drop off would be I think quite gentle closish to the panel. Which is good for instruments.

I would also expect heating from the panel would be los unless walls of the room reflect in the relevant IR frequency range.

This is also peak cat behaviour.


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[sgosnell]

They're just heaters, like any other heaters. They probably don't get as hot, so it can take longer to heat an area, but they work in exactly the same way. Same as a wood stove, or any other heater. If you give a heat source enough time, it doesn't have to be intensely hot to get a room warm enough for comfort, especially if the room is insulated to prevent the loss of heat. There's no magic, nothing new, just a lower temperature for the sources. It's all well and good as long as one has time, and the heat source is constant. A tiny space heater, or a kitchen stove hob will suffice just as well, given enough time and proper insulation. I think the thing that helps these devices work well enough is the large surface area. Big panels will heat an area faster than smaller, hotter heat sources.

[RJVB]

If it were my cat in the photo, he would be sitting on her right shoulder, for maximum heat absorption.

Ahh, but cats are perfect personal heaters, given how their normal body temperature is a bit higher than ours, they're small so their core isn't too far from the outside, soft, furry, don't smell and have very little perspiration. Only heaters with vibration therapy, too!

[Christian Miller]

1) Place cat in beam of IR heater
2) Use as hot water bottle


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[John A.]

1) Place cat in beam of IR heater
2) Use as hot water bottle


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My what a lovely cat you have. Is it a calico?
No, it's a convector.

[Reg]

Do you guys use mini-splits over there... In the states they are the least expensive, most efficient and easiest to install. No waves... just warm or cool air...LOL

What is a Mini-Split? - FUJITSU GENERAL United States & Canada

Reg

[RJVB]

Can't speak for the UK but in the continental places I know I've seen those (probably in their bigger form) only in hotels and restaurants. I was looking at heat pumps a while back, and the kind of subsidy we could get for replacing our (unused) fuel central heater with something modern like that, and learned that these air-to-air pumps don't (or hardly) get any subsidies at all because too inefficient. Only water/air pumps do, which are also much more of a drop-in replacement for central heating using warm water circulating in a closed system with radiators. Of course they only do heating (cold enough water to cool off a room significantly doesn't circulate anymore ) and they're hardly efficient north of the Loire river (a traditional north/south barrier) because there's just not enough heat to pump outside when heating is required. Which probably makes them even more efficient as neighbour harassment devices.

IMHO that's exactly the kind of heating responsable for the chronic threads about humidification.

[Christian Miller]

Can't speak for the UK but in the continental places I know I've seen those (probably in their bigger form) only in hotels and restaurants. I was looking at heat pumps a while back, and the kind of subsidy we could get for replacing our (unused) fuel central heater with something modern like that, and learned that these air-to-air pumps don't (or hardly) get any subsidies at all because too inefficient. Only water/air pumps do, which are also much more of a drop-in replacement for central heating using warm water circulating in a closed system with radiators. Of course they only do heating (cold enough water to cool off a room significantly doesn't circulate anymore ) and they're hardly efficient north of the Loire river (a traditional north/south barrier) because there's just not enough heat to pump outside when heating is required. Which probably makes them even more efficient as neighbour harassment devices.

IMHO that's exactly the kind of heating responsable for the chronic threads about humidification.

I’ve never seen them, which is why I’m intrigued. Heat pumps have had a lot of press.


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[Christian Miller]

I mean one simple thing we could do is, you know, properly insulate our housing stock…. But that would be craaaazy

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[Christian Miller]

My what a lovely cat you have. Is it a calico?
No, it's a convector.

I would say it’s mostly conduction in the case of my moggy.


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[RJVB]

I’ve never seen them, which is why I’m intrigued. Heat pumps have had a lot of press.

Of course they have, with the promises their manufacturers make (a bit like car manufacturers claiming their cars to be a lot cleaner than they turn out to be, IMHO).
I'm sure you must have seen those wall-wart units because it's often impossible to install them out of sight. Go to any modern hotel (B&B, F1, Campanile, Kyriad, etc) and the chance is good you'll see the interior unit, usually over the entry door because that's the easiest place to connect it.

BTW, a pulsed-air fridge is more or less a specialised form of such a mini-split, so if you have one of those ...

I mean one simple thing we could do is, you know, properly insulate our housing stock….

Considering the installation of a heat pump makes no sense without that. Not if you're really interested in the reduced electricity bill they're supposed to give you!

[Christian Miller]

Of course they have, with the promises their manufacturers make (a bit like car manufacturers claiming their cars to be a lot cleaner than they turn out to be, IMHO).
I'm sure you must have seen those wall-wart units because it's often impossible to install them out of sight. Go to any modern hotel (B&B, F1, Campanile, Kyriad, etc) and the chance is good you'll see the interior unit, usually over the entry door because that's the easiest place to connect it.

BTW, a pulsed-air fridge is more or less a specialised form of such a mini-split, so if you have one of those ...



Considering the installation of a heat pump makes no sense without that. Not if you're really interested in the reduced electricity bill they're supposed to give you!

I think we might be talking about different things


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[Reg]

Hey RJVB... they also have units that fit in attics or basements and use standard duct systems. The general point besides being efficient ... is they are electric, need low amp power and eventually when you get solar, etc... your only using the sun to heat and cool.

There is also the geothermal option with heat pumps. They just change direction of which direction the pump pushed the liquid for heat or cooling. But do cost.

The mini split direction costs very little compared to typical gas units... they work.

[RJVB]

Hey RJVB... they also have units that fit in attics or basements and use standard duct systems. The general point besides being efficient ... is they are electric, need low amp power and eventually when you get solar, etc... your only using the sun to heat and cool.

Of course, the water/water pumps, which do get subsidised here. They're a lot more expensive up front than existing gas or fuel alternatives though, and whether or not they're efficient in electricity will depend on how much heat there is to pump in the intended direction. Which really is heating only. The ones installed in northern Europe are typically hybrid models where a gas-fired or traditional electric heater jumps in or takes over if needed. As far as I've seen, of course.
Personal solar panels is another one of those things that which is in fact currently contributing to problems on the powergrid in the Netherlands, but that's another can of worms that I've mostly kept my nose out of. Here in France it has long been (and maybe still is) the case that you couldn't use the generated kWh directly yourself but could buy them back at a favourable price. Evidently more so in summer when we use much less electricity than in winter, when they're much less productive. Plus we can only install them on the north side of the roof because we live too close to a historical monument.

There is also the geothermal option with heat pumps.

Yup, we'd just need to dig up the "garden" and uproot all the trees in there

The mini split direction costs very little compared to typical gas units... they work.

Actually, I did look at an airco of that design some time ago, I didn't realise that before. So yeah, they're less expensive up front than a highly efficient heat source for a central heating system but that's really a bit comparing apples and pears.

[Christian Miller]

I want my own personal nuclear power station

The heating would take care of itself.


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[SoftwareGuy]

OK. I’m now wondering why, if all heaters are infrared heaters, there are specific heaters called infrared heaters?

The above discussion is incorrect. While anything with a temperature radiates heat as electromagnetic 'waves'; many heaters (like the ceramic heater blowing on my feet right now) heat the air by conduction.

Air move by the heating element, coming in direct contact with the element and itself is warmed.

Not all heat transfer is by infrared radiation.

[Christian Miller]

The above discussion is incorrect. While anything with a temperature radiates heat as electromagnetic 'waves'; many heaters (like the ceramic heater blowing on my feet right now) heat the air by conduction.

Air move by the heating element, coming in direct contact with the element and itself is warmed.

Not all heat transfer is by infrared radiation.

Convection, not conduction

Air is a thermal insulator

Unit 2 - Section B - University of Wisconsin-Stevens Point


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[SoftwareGuy]

Convection, not conduction

Air is a thermal insulator

Unit 2 - Section B - University of Wisconsin-Stevens Point


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The air is heated by direct contact with the heating element. The convection moves the hot air onto my feet. it isn't one or the other.

My point was the quote post said all heat transfers are via thermal radiation. That is not true, as several post discuss.

[starjasmine]

The same company also sells a model that's designed as a personal heater that you can put under your desk.

Hey RJVB - which company is that? I'm intrigued.

Because it is crazy-expensive to heat the whole house when the only room I am using most of the day is my home office, I've been using radiant space heaters of two kinds + a room humidifier in there for years without any mishap to guitars. The guitars are in cases in the closet when not actually being played, which keeps temperature swings gradual.

I have used two kinds of space heaters:

• One is old-school IR, I guess: it has these ceramic tubes that glow red + a small fan.
• Another is an oil-filled radiator type.

Both dry the air (as does central forced air, or really any heat source that doesn't also add humidity AFAIK) so I also run a little portable humidifier (steam, not utrasonic; I have hard water and dont want mineral powder covering everything).

My office is ~ 400 s.f. so this combo does a respectable job keeping the chill away and not turning the air bone-dry. I've found the IR heater to work a bit better than the radiator-type heater so I've used that over the other type for the past couple of years. I've been using one type or heater or another in this home office for a good 20 years, and I've owned all of the guitars in question for the same amount of time. My archtop is super clean: no cracks, crazing, etc. so I would say that this approach seems to work pretty well for me.

That said, I am within 30 miles of the N. California coast, which means that I don't have sub-freezing temps and I do typically have a pretty reasonable amount of natural humidity. When things get their coldest, I do find that the air drys enough to cause static sparks when I'm shuffling about the house. I even find that my cats act as natural capacitors, throwing a little static when I pet them. But I would say that the humidity generally stays at 30% or so. (It is summertime when I have to be careful to make sure that things don't dry out enough to crack finishes.)

So, this little combo works OK, but it takes all day for the room to heat up to where I don't wear a pretty heavy sweatshirt or sweater. I don't want to put that IR heater or the radiator heater under my desk - the heat would be too intense for comfort if I want to heat the room that way. But a little IR panel under the desk to generate supplemental warmth on my legs sounds good!

Thanks,

SJ

[sgosnell]

Heat is energy in a band of frequencies. It can be transferred/distributed in multiple ways.

[RJVB]

Poking around in the fireplace earlier tonight I wondered what I was struggling against ... IR radiation or convection? It gets a bit too hot for comfort!

Hey RJVB - which company is that? I'm intrigued.

As so often nowadays I can't find it again as easily as I thought, but here's an example of a brand that I can't remember:
https://amzn.eu/d/6GLxnCE

Other big brands that I know I have been looking at are Klarstein, Könighaus and Princess. I wouldn't be surprised if at least part of their product lines are shared.