Infrared heat

[SailinAway]

Originally Posted by John Mercier

Back to the question at hand...
Did you make a choice?

I spent a lot of time studying this today and didn't come to a conclusion. There are a lot of claims about the Dr998 infrared heater heating 1000 sq ft with the same 1500 watts that a ceramic heater uses to heat 300 sq ft---But also many reviews that say that claim is exaggerated. Reviewers who dismantled the DR998 found that it consists of 1 small quartz tube and 1 PTC element, whereas other brands have 4 to 6 quartz tubes. They report early failure of the quartz tube. Another concern is the long time it takes infrared to heat a room---45 minutes to raise the temperature 5 degrees.

I did finally come across an explanation that helped me understand infrared heat: you can feel the warmth of the sun on your face in the winter, above the air temperature. That's after the sun's infrared rays traverse 93 million miles of space at minus 454 degrees.

I did buy a full tank of oil last week for $4.29 a gallon. Very glad I did that, as the price rose immediately afterward. Still trying to get my wood split to save the oil for December through February.

[John Mercier]

I figured the space heater was more about heating just you than a room or the whole house... which is what I presumed the oil boiler would do.

The wood stove, which also works by radiant heating, generally does well with a room... but it does take some time to get the room up to temperature.

[SailinAway]

Originally Posted by John Mercier

I figured the space heater was more about heating just you than a room or the whole house... which is what I presumed the oil boiler would do.

The wood stove, which also works by radiant heating, generally does well with a room... but it does take some time to get the room up to temperature.

I spend most of the day in my 12 x 12 office. I use a space heater for the between seasons---Sept, October, March-May.

[DickR]

Originally Posted by John Mercier

...
The wood stove, which also works by radiant heating, generally does well with a room... but it does take some time to get the room up to temperature.

A wood stove disperses heat by both modes, by direct radiation to surfaces facing the hot surfaces of the stove and by convective air currents, heating up air flowing in from near floor level, passing over the hot stove surfaces, and continuing on up to ceiling level and outward toward other parts of the room or up a stairwell. Both modes distribute a significant amount of heat, but convective distribution does more of the total heat load. Still, distribution by air flow induced by density differences in general is slower than when a force air heating system's blower is moving it, as you point out.

For those interested, any surface radiates heat outward at a rate proportional to the fourth power of its absolute temperature (Rankine or Kelvin). The nature of the surface (dull black vs light shiny) determines its emissivity.

[John Mercier]

The electric radiant heater, and the electric convection, will also do both.

It is the dominate function that they are pushing.
Neither is operating in a vacuum like the Sun... and air molecules do absorb radiation.

[brk-lnt]

Originally Posted by SailinAway

I spent a lot of time studying this today and didn't come to a conclusion. There are a lot of claims about the Dr998 infrared heater heating 1000 sq ft with the same 1500 watts that a ceramic heater uses to heat 300 sq ft

Every heater that plugs into a wall outlet will produce the same amount of heat for a given amount of electricity (cost). Some, like an infrared heater, can help you direct the heat to a certain area. Others, like oil-filled heaters or oscillating fan type heaters help distribute the heat more evenly around the room. But they all work on exactly the same principle.

You have to decide if your goal is to heat an area, or a person (you).

[John Mercier]

Radiant and convection move heat in different ways.

Convection heats the air; While radiant heats the objects.

Some radiation will be absorbed by air molecules... but generally not all.

[ApS]

Originally Posted by John Mercier

Radiant and convection move heat in different ways.

Convection heats the air; While radiant heats the objects.

Some radiation will be absorbed by air molecules... but generally not all.

A hair dryer--or "a heat gun"-- is a convection heater.

[John Mercier]

Correct. They also give off a percentage of the heat as radiant.

Sort of like a light bulb is about lumens, but also gives off heat. But given the same amount of electricity, some will provide more lumens... others more heat.

[Woodsy]

Its pretty funny reading some of these...

For power calcs use Ohm's law. 800W is 800W! The reason most hair dryers are limited to less than 1800W is because 120V/1800W = 15A. Most household 120V circuits are limited to 15A, and will nuisance trip at 13.5-14A depending on circuit load. You can have a dedicated 120V/20A circuit but they are pretty rare in a home and will nuisance trip at anything over 18A.

A 120V/1200W heater of any kind will pull 10A.

All of the electric heaters discussed here are convection heaters. They use electricity to heat air, and they will all heat a room slowly. The marketing geniuses just push "how" the devices use the electricity to heat the air.

Woodsy

[SailinAway]

After reading more about heaters, it seems to me that the question is, How much heat will I get with a certain type of heater? I think that should be measured not just in the obvious "1500 watts is 1500 watts," but in the perception of comfort.

I just spent a couple of days sitting next to a small ceramic heater in a 144 sq ft office. It took hours for the room to warm up to just barely tolerable rather than freezing. Touching my clothing and objects near the heater, they are cool to the touch. If I get up and move to the other side of the room or leave the room, I am immediately cold. If I open the room door, all of the accumulated heat is lost within 30 seconds. This indicates that the heat is not being stored in objects.

On the other hand, when I get up from a warm bed in the morning, I notice that I carry the stored heat in my body and clothing for quite some time, even when it's 52 degrees in the house. If I exercise outdoors on a cold day, I will warm up and stay warm for at least 30 minutes after I get back to my cold house.

So it seems that there is quite a bit of value in this stored heat, making me lean toward getting an infrared heater.

Also, reviews indicate that the perceived amount of heat emanating from different types of heaters varies a lot, even when they are all 1500 watts. There is quite a bit of agreement that the Dr-968 can warm a larger room than my small Lasko heater. I conclude that this is due to the value of the heat stored in objects, the body, and clothing from infrared heat, which lasts for awhile after the heater is turned of or as you move around the house.

Unfortunately manufacturers don't usually justify their claims about heat ouput. DR Heater says, "Wattage indicates the amount of electricity needed to power the heater--not the amount of heat it can deliver. Dr. Infrared Heater’s advanced heating system enables greater heat production without using any more power with a high-efficiency blower that delivers an average of 250°F at 3.5m/s to your room versus competing heaters that can do only 155°F at 2.2m/s." That makes me wonder if some of the wattage is going to the blower rather than producing heat.

[John Mercier]

https://www.thespruce.com/best-radia...eaters-4078803

[ITD]

Also keep in mind that heat is constantly exiting a structure. The rate at which it happens is dependent on the type of structure, insulation and how tightly it is sealed. Also important is the difference in temperature between the area you want to heat compared to outside temperature. The colder it is outside, the more heat it will take to keep the space inside warm.

And it is also very important to remember that you need to keep a house heated or your pipes will freeze. Keeping an electric heater going in one room while not heating or keeping the rest of your home too cold will turn into a disaster for you.

[John Mercier]

She is looking for the sensation of heat.

The sun on your face.

[brk-lnt]

Originally Posted by SailinAway

So it seems that there is quite a bit of value in this stored heat, making me lean toward getting an infrared heater.

You're still going to have the problem of the general space being too cold, so when you get up to move, you'll likely feel cold fairly quickly.

Heat is a "thing" (vs. cold, which is not a physical thing, it is just the absence of heat). Objects can store heat, much like wet clothing stores water. You can think of objects storing heat similar to a sponge absorbing water, the outer layer will heat up first, and then the heat will be coducted further into the object and stored. Depending on what the object is made of, it will affect how long it takes that object to absorb heat all the way through, and how long it takes to release it.

If you want to eliminate the cold drafty feeling of a house or room, you need to heat the entire room, and you need to hold that temperature long enough for the objects in the room to stabilize at that temperature. If you blow a little bit of warm air into a room, it will quickly go back to feeling cold, because that little bit of heat ultimately gets evenly distributed to ALL the objects in the room. Again, think of it like water, you're not going to fill a room, or make all the objects in a room wet, with an insufficient quantity of water. Ceramic vs. infrared heaters is like comparing different kinds of buckets, it really doesn't matter much if you don't have enough water to begin with.

[Woodsy]

SailinAway....

BRK-Int has it explained perfectly.

Nothing is better than a temp stabilized room/dwelling... I doubt any 120V electric heater will do the job efficiently.

All of the heaters mentioned here are convective (even the infrared ones). They heat the air and in turn the air heats the objects (mass) in the room. I might also argue the amount of energy needed by the smaller heater may not save you any $$. But it will keep your work area warmer.

If you want some serious heat, but are OK with some hazard, look into the propane heaters for bobhouses etc.

Woodsy

[John Mercier]

You mean the Little Buddy Radiant Heaters?

We sell those. We even sell the propane cylinders.

[SailinAway]

Conclusion after reading all of the above: No, infrared heaters don't save money as claimed compared to other types of heaters and they don't heat a room or a person any better than other types of space heaters. Is that the consensus?

[John Mercier]

I don't know.
Woodsy just suggested a radiant heater... that is what the Little Buddy heaters used to keep the bobhouses warm are.

We sell electric convection heaters. Both the fan types (fans use some of the electricity) and the large surface type.

I find the radiant give a near instant sensation of warmth even when not sitting too close, while the convection ones - unless we trap the heated air under a desk or something - require more time for me to get the same sensation.

When I shut down the radiant, I still to feel cooler almost immediately; when I do the same with the convection there is a slight cooling (I think mostly due to the lack of the fan), but the room overall seems to stay warmer for a while.

The Little Buddy has a new smaller version that at least seem to make it more bearable to be in front of for a longer period of time. I found the original to seem to make it too hot and would move from in front of it to the side, and then move back to the front as I felt cold.

[ITD]

I have a little buddy heater, and it is great, outdoors. I wouldn't use it indoors. You have a fire hazard plus a carbon monoxide potential hazard.

Sailin' I think if you want to have a supplemental source of heat, an infrared heater is fine. I would suggest a tower type or a floor model that focuses on you. A 1500 watt model with 3 heat settings and a remote control would probably work well for you. That way you can adjust to the conditions of the day. This would allow you to lower the heat in most of your house, while keeping the area you sit in comfortable.

Just keep in mind that there are at least a few people a year who lose their homes to fire started by small electric heaters each year. Usually by using them too close to combustible materials.

There seems to be and endless choice of heaters out there. Pick something that floats your boat, just make sure it has overheat protection for added safety.

[John Mercier]

The new ones are designed indoor safe with special features.
They could start a fire the same as other heat sources, and they would add humidity to the house.

Propane not exactly being cheap either.

[pondguy]

Todays 10 day Kero price is $6.399 per gallon time to lower the thermostat.

[SailinAway]

Well, after 6 weeks of being cold, I checked the chimney for storks' nests and started up the woodstove. Ahh . . . bliss . . . except for the thought of all the remaining cutting, splitting, stacking, hauling, restacking, feeding, and sweeping ahead.

[ApS]

A cold-wave came through Central Florida last night. Perhaps the windows should have been closed last evening!

At 7-AM--and 60°--the little convection space heater got switched "on" in the bedroom. After 20 minutes, the bedroom got toasty at 80°, so it got turned down. One minute later, the whole neighborhood lost power!

Fortunately, there's a radiant 1873 "parlor stove" in the living room that takes wood or coal. (Coal--hard to start--burns too hot).

Originally Posted by SailinAway

I spent a lot of time studying this today and didn't come to a conclusion. There are a lot of claims about the Dr998 infrared heater heating 1000 sq ft with the same 1500 watts that a ceramic heater uses to heat 300 sq ft---But also many reviews that say that claim is exaggerated. Reviewers who dismantled the DR998 found that it consists of 1 small quartz tube and 1 PTC element, whereas other brands have 4 to 6 quartz tubes. They report early failure of the quartz tube. Another concern is the long time it takes infrared to heat a room---45 minutes to raise the temperature 5 degrees.

I did finally come across an explanation that helped me understand infrared heat: you can feel the warmth of the sun on your face in the winter, above the air temperature. That's after the sun's infrared rays traverse 93 million miles of space at minus 454 degrees.

I did buy a full tank of oil last week for $4.29 a gallon. Very glad I did that, as the price rose immediately afterward. Still trying to get my wood split to save the oil for December through February.

Humanity can't rely on the sun for radiant heat--look at Greenland!

This reminded me that I may have owned every form of plug-in space heater ever made! (Plus one Kerosene radiant heater, and one propane radiant heater).

I may have donated my ceramic heater--a very disappointing manner of heat--IMHO.

The stand-up quartz radiant heater is too hot to be near and has only one setting. When the thermostat kicks in, it makes a startling sound like a welder sparking.
The corded baseboard heater is OK. It does take up a lot of floor space, but you can sit right next to it and be comfy.

The trouble with convection heaters is that any heat they produce rises to the ceiling and is eventually lost. Our industries have crafted an expensive way to move about rooms heated to a comfortable "thermocline".

My 1950s 800-watt radiant heater "dish" at our Wolfeboro cottage is the clear winner. Instead of mounting it at 8 feet above the floor, I should have had it professionally wired and bolted at the peak of the ceiling (at 16-feet). Left "on" while sleeping, the largest room in the cottage gets warmed with only 800 watts. Everything affected within the arc of the reflector is warmed.

A warm floor is a nice way to greet an Autumn morning.

[John Mercier]

brk-Int,

The relative concept working in my head is that the incandescent bulb and the convection heater use the same basic technology.

The IC being tweeked to produce more light (smaller element and a vacuum), while the heater tweeked to produce more infrared (heat)... neither being perfectly efficient due as noted by a mixture of the IC getting hot, and the heater elements giving off a visible light red glow.

The original diodes (mixing of elements) produced infrared. They were tweeked to get red visible light, then green, and finally blue. The efficiency of the process allows for a narrow EM signature, and thus less loss.

The modern IR heater is also a tweek. The tweek being to produce less light and more IR... first ceramic... and now quartz (with less loss, but still not perfect).

This improves IR (heat transfer) without the pressurization of the space.
Basically, it doesn't heat the air near the elements... have the air carry the heat to the ceiling and look for the nearest exit through air leakage.

Most loss of heat is through air leakage.

Electric doesn't have a flue... so no flue losses.

But it can not escape entropy.

And the Laws of Thermodynamics would not allow for a heat pump to be more than 100% efficient... but we compare the transferred BTUs to the produced BTUs of a conventional heater and that is what provides the greater than 100% efficiency rating.

The relation is built on the traditional technology; and is considered apparent efficiency.

[ITD]

Nothing, or maybe more accurately very few things escape the laws of thermodynamics, properly considered. Heat pump hvac units use electricity to heat a space. The amount of heat generated, or perhaps more accurately transferred by a heat pump is many times that which would produced if the same amount of electricity were used in a resistive heater to heat the same space. And it all obeys the laws of thermodynamics.

This is why using terms like "efficiency" can be confusing when considering how to heat a space. Resistive electric heat sources are 100% efficient when you consider that all the energy consumed is changed into heat.

But electric resistive electric heat sources are one of the most expensive ways to heat a space.

[John Mercier]

It is quite cost effective as compared to heating the building or a room that is not easy to heat by other means.

The reason that you see so many camps/cottages/condos in NH with electric space heating *usually not the small space heaters* is the cost to install was so much lower, and the maintenance nearly none existent.

When the structure was to be used late in the season or annually, the electric heaters would only be used as a backup to the primary (usually a wood stove).

I know several homes in the area that have that, and before being changed out... all three of our family cottages worked that way.

Each room could be turned on or off, and plumbing was highly centralized with interior ''wet walls''.

While temperature control was very precise... it was a lot of thermostats... and since once the cottages got used for more than the summer, the electric became a secondary.

I ripped some of the radiant out of the ceilings, but left it in the bathroom floor and walls.

[brk-lnt]

Originally Posted by John Mercier

brk-Int,

The relative concept working in my head is that the incandescent bulb and the convection heater use the same basic technology.

The incandescent bulb, convection heater, and IR heater all use the same core principle - resistance of current flow. All 3 of those (and while we're at it, every other form of electric heater) produce the desired output (heat, or light) by exploiting the basic rules of physics and electricity as needed to produce what is really just a convenient side effect (heat or light) of electron flow through various materials.

In the context of these threads, SailinAway appears to be concerned not just about feeling warm, but about ensuring her house is sufficiently warm enough to prevent damage from things like frozen pipes. So, we need to advise in the context of heating a room or dwelling, not just creating a perception of increased comfort.

As I mention in another thread, and I think you are aware, heat is a physical object. For these conversations we can draw a lot of analogies using water instead. People can see water, whereas they can't see heat, so it's sometimes easier to understand.

Instead of heating a room, imagine filling a swimming pool with water.

Let's say we have a 15,000 gallon swimming pool (room) and two hoses with nozzles (heaters) that we can choose from to fill the pool. Both hose/nozzle combos have an output flow rate of 1500 gallons per hour (watts). One nozzle has a large spray pattern, and one has more of a concentrated stream output, but it is important to note, they both deliver the same amount of water over a given time period. If it's not clear, the spray nozzle is the convection heater, and the stream nozzle is the IR heater.

If we want to take our swimming pool from empty to full, and the pool is 15,000 gallons, and either nozzle option delivers 1,500 gallons per hour, we can see that it's going to take us 10 hours to fill the pool either way.

Now, if we don't want to go swimming (heat the entire room) and we just want to cool off (warm up) quickly, using the nozzle with the stream output to hose yourself down will cool you down pretty quickly because you can direct all of the output just where you want it, instead of in a large spray pattern. This is the primary benefit of the IR heater, it is producing the exact same amount of output, but directing it in a smaller area. It won't heat the room/fill the pool any better, faster, or cheaper overall, but it can give a perceived level of working better via the directed output.

If we have another source of water/heat, like a wood burning stove, then an IR heater might be a better choice for auxiliary heat than a convection heater because it would let us focus the additional heat just on ourselves, instead of spraying it around the entire room, with only a little bit directed to us.

However, if we are filling a pool/heating a room, both are going to take the same amount of time, and have the same operating costs, for a given output rating.

If you are heating with electricity, the only way to save money is to use less heat. You can make the room temperature lower, or you can heat less area (eg: close doors to unused areas), but until our laws of physics change, all your options or form factors are exactly the same.

The above examples are based on using electric heaters, essentially creating heat from "nothing". This is in contrast to a heat pump, which moves heat instead of creating it.

We can belabor our swimming pool example by envisioning that we have access to a large body of clean water someplace, and we have a giant sponge. You can use the sponge to soak up this "free" clean water, and then squeeze it out into the pool, repeating the process until the pool is full. This is the basic principle of a heat pump.

If we have plenty of free water available, this process works well and it will use less energy (water) than buying water from a supplier via a hose (buying power from the electric company). We can automate this sponge squeezing with a couple of motors, and while the motors cost money/electricity to operate, 1500W of motors might be able to squeeze sponges equivalent to 5000W of the direct method. (I know, it's getting weird with motors squeezing sponges, I said it was going to be a bit of a belabored example).

As our free water supply diminishes, it becomes harder to fully saturate the sponge, and it takes more work to squeeze all the water out and into the pool. We might got from using 1500 watts of motors to get 5000 watts of equivalent output to only getting 3000 watts, and then 1500 watts, and then even potentially only 500 watts, making the sponge/free water example MORE costly to operate when the water supply is down to the last few drops.

Similarly, with a heat pump, as the outside temperature drops, there is less "free" heat in the air, and the equipment has to work harder and longer to extract it. At some point it becomes impractical to move this free heat/water effectively and we have to resort to hoses/resistive heaters. This is why your cold weather climate heat pump will often have an emergency/aux heating option to resort to heat creation instead of heat movement when it is too cold outside and/or the demand for heat inside is greater than what the pump system can provide.

Apologies for the long response, hopefully it helps clarify some of the concepts.

[John Mercier]

She isn't going to protect the pipes in her house with a space heater of any format.

The analogy you are using doesn't work.
She wished to heat only herself.

The larger spray pattern of the nozzle would mean the heat is wasted into the surrounding...

And once vaporized it would escape the area as humidity.

The loss of water can range compared to the total... but the loss is an inefficiency.

So while you are spraying the same amount of water (1500w in our example), you are not getting the full effect of the water toward the purpose (<1500w worth of real world results).

The narrow spray pattern... with less dribble at the nozzle... will be more effective in the process being attempted. It is for all intensive purposes more efficient in the real world application.

[granitebox]

Dear God let this thread die. At this point its a personal preference, there is no right or wrong -

[TheProfessor]

Originally Posted by granitebox

Dear God let this thread die. At this point its a personal preference, there is no right or wrong -

Exactly.

Tho original poster has stated that he/she is using a wood stove. So forget the ambient temperature of a burning electrical cord.

[SailinAway]

Originally Posted by TheProfessor

Exactly. Tho original poster has stated that he/she is using a wood stove. So forget the ambient temperature of a burning electrical cord.

True. An easy way to settle this dispute would be for me to get a large box-style infrared heater from Home Depot, do a quick experiment with it, and return it to HD. Not entirely ethical but if it turned out that the infrared heater was better at warming up my office, I might keep it to use in the between seasons, because I don't think short fires on a cold morning are good for the chimney.

[John Mercier]

You can actually just do it in the store.
When I was in their garden department years ago...
I would show the difference between the two to the customers.

Standing in front of the IR they would sense more heat, and placing their hand over the top of each they would feel the hot air rise from the convection.

I also explained that since their was a maximum wattage that was put out from the wall outlet - they overloaded the one there more than once - that more elements did not increase the heat output... it allowed for the user to ''turn down'' the heat by having the appliance shut off power to one or more of the elements.

Using less power made the system more efficient since the operator felt warm, but not overpowered. Most units only had two back in those days, so the option to turn it down was rather limited.

Ceramic to quartz was an upgrade as the ceramic had more conduction than radiation in relation to the total.

[LikeLakes]

John your post made me think of making just one more comment, not sure if it was mentioned before. Many/most of the houses and camps built some time ago are wired with 14 gauge and protected by 15 amp breakers or fuses (hopefully, I've seen people put 20 amp fuses in place of the proper 15's). If you put a 1500 watt heater of any type on one of those circuits, it should be the only thing on that circuit. Obviously a few 8 or 11 watt LED bulbs won't make a difference but you shouldn't have other items on the circuit.

[John Mercier]

Originally Posted by LikeLakes

John your post made me think of making just one more comment, not sure if it was mentioned before. Many/most of the houses and camps built some time ago are wired with 14 gauge and protected by 15 amp breakers or fuses (hopefully, I've seen people put 20 amp fuses in place of the proper 15's). If you put a 1500 watt heater of any type on one of those circuits, it should be the only thing on that circuit. Obviously a few 8 or 11 watt LED bulbs won't make a difference but you shouldn't have other items on the circuit.

Sorry. I didn't see this earlier.
You make an important point. Especially since some rooms would only have a single circuit dedicated to them, so no other appliance would be able to used without risking overload on the higher power models.

[SailinAway]

Originally Posted by John Mercier

. I also explained that since their was a maximum wattage that was put out from the wall outlet - they overloaded the one there more than once - that more elements did not increase the heat output.

Good point, John. Thank you.

[John Mercier]

Originally Posted by SailinAway

Good point, John. Thank you.

The more elements is really an attempt to create more efficiency in the application.

The early versions only had three settings, 1500w, 750w, and off.
Both elements were on for 1500w, one was on for the 750w.

So you could turn down the heater if you felt too hot.
The IR heaters, especially the quartz, could become overbearing... and the user would turn them down.
The industry, most likely because the cost of operating them, added more elements so the units could be turned down further.

I first saw this in the resistance heaters. They made them look like fireplaces with a ''lightshow'' and sometimes would use a fan that had multiple settings based on a temperature setting that could be found on a digital display.

[TheProfessor]

Originally Posted by TheProfessor

Exactly.

Tho original poster has stated that he/she is using a wood stove. So forget the ambient temperature of a burning electrical cord.

It is dead. The wood stove is being used. No improper wiring. That could burn down the entire house.

[TheProfessor]

Originally Posted by TheProfessor

It is dead. The wood stove is being used. No improper wiring. That could burn down the entire house.

Please. Stop quoting yourself !

[SailinAway]

Originally Posted by TheProfessor

Please. Stop quoting yourself !

HAHA! Funny.

[ApS]

Sailin--Here's a lead to radiant heaters of 300 (low) watts--just not Amazon.

https://www.wayfair.com/v/bic/compar...ND10051&piid5=

There's a 300-watt radiant heater available that is ceiling-mounted. (What I like). Unaccountably, it's priced at nearly $140.

[ApS]

While checking on the benefits of infrared heaters, I stumbled on this video at YouTube:

https://m.youtube.com/watch?v=ZdiUnmpOgqE

The video "sounds" like clickbait at the start, but the author is not selling anything and this study appeared in Elsevier, which doesn't publish just any medical study.

The author, a medical doctor, tested a low-level infrared lighting in ICU. Placing LED vests on patients suffering from recent influenza, half of the blind study left the hospital four days earlier than those whose vests were intentionally never turned on! (Being a blind study).

At 25:00, the author goes on to explain how modern life habits have made us more exposed to deadly viruses. For example, the "Low-E" glass in modern windows stops healthy infrared rays from reaching us indoors.

Quoting both modern studies, medicine from 1919--two years into the Spanish Flu--and quotes from 1871, it was found that sunlight--especially in winter--is a great help. Sunlight has multiples of the near-infrared than that given in the study's very weak vests.

It was noted that sunlight--especially with green leaves nearby--was especially effective. (Leaves reflect near-infrared rays). City-dwellers are especially negatively affected.

Snowmobilers will be relieved to know that the near-infrared rays discussed penetrate clothing.

ROS (Reactive Oxygen Species), latitude, and melatonin are discussed, but the quest for infrared heater benefits must go on.

[John Mercier]

IR is registered by the body as heat.
You don't need heat passing through windows.
If you have ''heated'' your home in any way; all surfaces are giving off IR radiation.

The Low E will also block this IR from leaving your home through the glass.
It doesn't block 100%, but enough to impact heating and cooling costs.