Great silent heater for medium-sized room. Relatively child-safe.

This unit is an update of the Holmes / Bionaire BH-3900 which I have also reviewed. Please read that review for the safety concerns with the older model. I own both, and used both this past winter. I liked the BH-3900 so I bought the updated model BH-3950 a month later a different store. (Also note that Bionaire model number BNRBH3950U seems to be identical to Holmes model BH-3950.)

How does this model differ from the BH-3900?
There are three changes that I can see, and all are improvements:

(1) The two-knob design has been abandoned in favor of two switches and a temperature-setting knob (described below) See the previous review for why this might have been changed.

(2) There are three large vanes mounted diagonally in the BH-3950, whereas the BH-3900 has eight smaller vanes mounted parallel to the width of the unit. Look closely at the two epinions pictures and you can see what I mean. Why the change? I assume three larger vanes get the same amount of heating surface area in the same space for less than it costs to manufacture eight smaller ones. Simpler design, plus more radiant heat is directed out the sides of the unit with the diagonal mount.

(3) The BH-3900 has four small caster wheels, two on the front set of "legs" and two on the back. The BH-3950 has two larger wheels, on the back, and two wheel-less legs on the front. A close look at the pictures also shows this change. I assume this change increases stability, and makes the unit less likely to accidentally roll somewhere if nudged.

Unlike the epinions specs for the BH-3900, the epinions specs here are correct. The BH-3950 is fanless, has an analog thermostat, a low and a high power setting, and operates almost totally in silence.

I will repeat a few things I mentioned in the other review:

The heater is "micathermic," which means it uses thin panes of heated mica to generate heat. This new noiseless technology is a real improvement compared to the typical "pinging" of oil-filled heaters as they heat up. Moreover, there's no hot oil to spill out if the heater is punctured, rusts out, etc.

Unlike ceramic heaters which have a very hot but small heating element in one place, the micathermic heater generates heat using these large, thin panes, so the heat is more evenly distributed around the body of the heater, eliminating really hot spots and the need for a fan. This heater heats only by infrared (radiant) heating and convection.

Usage
I use this heater to heat a cold bedroom in the basement. The bedroom is 330 square feet. It typically stays in the low 60s, sometimes a little colder on a cold, cold Virginia winter day. I wanted to get the temperature up to low 70s, which is comfortable for me. This heater was used a few times a week for about three months.

Set-up and settings
Set-up was easy: attach the feet and wheels and you're ready to go. Took me about 10 minutes, including unwrapping the sufficiently protective packaging. (Don't hesitate to push the feet firmly into place, like the instructions say.)

Plug it in, and away we go. There are two switches. Switch 1 is power: on and off. This switch is illuminated. When the unit is heating, the switch is lit. When you've reached the desired temperature and the heating elements are switched off, the light goes out with a slight metallic "click" noise. I find repetitive noise distracting, but I don't mind this heater turning on and off every ten minutes or so on a cold day. If you have any background noise in the room at all, it is inaudible.

I like this improved design because the status of the heater is easy to see. It is very easy to tell whether it is switched on by the position of the switch (unlike the BH-3900) and you can tell whether it is heating right now or not (useful if you are sitting a long way away from the heater and wonder whether it needs to be turned up or down).

Switch 2 is low or high power. "Low" power draws about 500 watts, and only energizes one of the three panes. High power draws 1500 watts and energizes all three panes. High power mode does not come with a thank-you card from your electric company, but they are thankful just the same. (Actually, this unit saved me money ... see below.) But this power consumption is reasonable for an electric heater. Ever see what your electric clothes dryer draws? Mine draws 5250 watts!

The knob is the thermostat. Basically, you turn the unit on, set the knob to max, and wait until the room heats up to the desired temperature. Then slowly turn the knob down until you hear a slight "click" of the heater switching off. Now the heater will maintain the room at this temperature by cycling on and off as necessary. A tweak or two of this knob was all I needed to do to set it correctly for my room. The knob has no degree markings, you have to "wing it" as I described to set your desired temperature.

Performance
Performs identically to the BH-3900.

In another review, I was dissatisfied with a fan driven unit. The one merit of that unit was that it threw a lot of heat quickly across the room. I was afraid that this fanless model would take a long time to heat up the room. Not so. During the first minute or two, you might hold your breath a little, since it takes that long to heat up. But once it gets going, the infrared heat from the vanes can be felt up to five feet away, and once the convection currents start the air circulating around the room, it heats up nicely. It heated the 330 square feet of bedroom (which measures 22' x 15' and has just one window) a few degrees in about a half-hour. I'd say this size room is just about right for this size heater. It also worked well in the cold 400 sq. ft. room above my garage, which has three windows. Here it takes about an hour to raise it about 5 degrees. Holding the room at that temperature is easy after that, but I have a newer home with good insulation (but awful windows), so your results may vary. Obviously if you have a barn loft with wind whistling through the walls, you're not going to do well with this unit.

When we go outside in the snow, I set this unit up in the hallway, and we huddle around it and warm our hands over it. It takes just a few minutes to get nice and warm.

My two biggest concerns
I had two major concerns when purchasing this unit:

(1) I have a toddler who runs around the house.

Unlike the supposedly child-safe unit that I had packed up and returned ASAP because it could easily burn your finger on its heated metal grill, the Bionaire BH-3950 has a much safer design. Even after it has been on for a while, the metal grill does not get alarmingly hot. There seem to be two reasons for this. Unlike the unit I returned, the heated air does not travel through the metal grill on its way out. Instead, the Bionaire is designed so that the hot air naturally rises out the top, and cooler air is drawn in from the bottom and the sides. Now, the radiant heat from the vanes does heat the metal grill surrounding them, but this grill is coated with some kind of plastic-like coating that minimizes heat transfer. (Half the reason why metal can burn you so quickly is that it transfers heat quickly, unlike, say, glass. Compare when you briefly accidentally touch a glass baking dish versus a metal oven rack even though both are at the same oven temp -- the rack burns you immediately because it transfers heat quickly to the skin.) So even though the sides of the unit do eventually get pretty warm, you can put your hand on it momentarily (say, 5 seconds) and not get a burn. Obviously you would be a completely irresponsible parent to leave your young child unattended around a hot heater for any period of time, but with the Bionaire BH-3950, I don't worry when my two year old daughter runs into the room. If she knocks it over, the unit has an automatic tip-over protection. If she touches the grill momentarily, it might hurt a little, but we're not going in for a skin graft or a serious burn.

The tip-over protection is so sensitive that when I pick up the unit abruptly to move it a few feet, I notice it temporarily switches off, and it comes on after it has been set down again. I like this feature.

My toddler has run into this heater once, tilting it, but without knocking it over, and it momentarily shut off, turning back on once it rocked back onto its feet.

The BH-3950 gets my vote as far as toddler safety is concerned.

(2) Fire safety

Risk of fire is a concern with any high-wattage appliance, especially heaters. Be sure to heed all the warnings: don't use an extension cord, don't put it right next to the wall, under drapes, near papers etc. etc. Most of this is common sense.

Read my review of the BH-3900 for concerns about the older design. I have not seen similar concerns about the new controls, but this model only has one other review so far, so only time will tell.

Lightweight
This model weighs about fifteen pounds. I can easily move it with one hand. It is very easy for my wife to move around the house and carry down the stairs.

Actually saved me money
Not on the electric bill, but on propane! My house has central air and heat, and the heat is fueled by propane, which gets a bit pricey in the winter.

I bought the aforementioned BH-3900 for the basement, which is cool year-round (an asset in the summer). But my wife likes to be toasty warm in the winter -- her ideal temperature is 78 degrees. So I bought a second unit to put in her room. Now we can turn the heat down in the whole house at night, she doesn't freeze, and we save money.

We also have a big window over the front door. If you stand under this on a cold day, you can feel the cold draft. So one day, I brought the heater into the front hallway and set it up below the window at night. To my surprise, the whole-house heat came on a lot less frequently all night long. By "cancelling out" my biggest draft with this heater, I surely paid the electric company, but I saved on propane, which was a net savings overall. Plus the wife is toasty warm. Hurray BH-3950!

Any negatives?
None apparent. If you were obsessive-compulsively unable to tolerate any noise, there is that slight occasional click-on click-off sound when the heater is holding a certain temperature. This does not annoy me, even though I hate repetitve noise, and it is hard to hear across a large room except in complete silence.