baseboard heater under built in bookcase

kaycee

We installed our new built in bookcases over the existing 6' electric convection baseboard heater. But we should have left more head space. We covered wood with foil bubble insulation. turned on the heater (remote thermostat) and the insulation was very hot and the wood was very warm. I have an idea (other than investing in three kick toe heaters) : make a heat deflector out of sheet metal. see attached sketch. I would keep the foil insulation in place and leave an air gap between the insulation and the sheet metal. i would bend the sheet metal at a slight angle to direct the heat downward. the deflector would be six ft long as is the heater. Do you think this might work? what is the worse that could happen if it doesn't work....

Paul Pollets

Enclosed radiators need 2" above, 1-2" below, louvers on top and 2" on the sides. If not, you've boxed in the heat and will get little output.

JUGHNE

If this is a 6' 240 volt electric BB heater that is 1500 watts of heat buried under a wood box. I just looked at my toaster, it is rated at 850 watts. So you have 2 toasters under there......not a good deal. Just for instance the code allows no outlets above electric BB heaters because danger of melting cords etc.
The worst is that the foil bubble insulation will burn and be kindling for the wood ignition. For real.

I would abandon the ele BB and install cove heater at ceiling.

kaycee

1. the heater isn't hydronic...just electric, convection
2. foil bubble insulation is fire rated....approved by the Reflective Insulation Manufacturers Association
3. there is open grill work on the front...so i didn't really 'box" in the heat but close
4. BUT yes it gets hot....thus the deflector in the attachment. i just saw heat shields for above fire place made out of steel with an air gap....sort of the same thing although much further from the source (yet the source is a fire and much hotter)
5. I saw in finehomebuilding.com that they used drywall to protect the underside of their wood bookcases....(but there heaters were hydronic which work differently but heat is heat) I would be afraid of igniting the paper coating on drywall


BUT thank you all for the suggestions...it gave me 'food for thought'. i think I will try it with a short section of some 22 gauge steel I have in the garage....see if the wood stays cooler....

Zman

1. Electric heaters run much hotter than hydronic and frequently catch things on fire
   
2. Bubble insulation is flammable.
   
3. You are boxing it in. It is not designed or rated for this.
   
4. Drywall paper is flammable. Not as flammable as reflective insulation though..
   

Putting a regular baseboard heater in a small wooden box is crazy. No combination of heat shields is going to make it safe.
Would one of these work for you? https://www.amazon.com/Marley-QTS1504T-Electric-Toe-Space-Heater/dp/B001MXC2NC/ref=sr_1_5?gclid=Cj0KCQiA0NfvBRCVARIsAO4930kZQZKzmxkQgENOrq_aQuJzha0DZh1i-X7bZ8zvKZXwjO71T55LMbAaAvv_EALw_wcB&hvadid=399673740173&hvdev=c&hvlocphy=9028830&hvnetw=g&hvpos=1t1&hvqmt=b&hvrand=17006120007376162557&hvtargid=kwd-352323301862&hydadcr=7467_9611910&keywords=electric+toe+space+heaters&qid=1576460541&sr=8-5 It has a fan to move the heat out as well as a metal box and high temp safeties. It has been UL tested for the application

JUGHNE

The fireplace air space is designed such that it has a free flow of air by gravity.
Heat might be heat, but at what temperature? The hottest water in baseboard heaters might be 180 degrees.
Would you lay a piece of the bubble foil insulation on top of your toaster and expect it to not burn? You have 2 toasters under the bookcase. IMO

EBEBRATT-Ed

@kaycee
You should listen to @JUGHNE

You may not like the answers but there is nothing you can do to make this right.

You have a fire hazard in the making.

Without the proper airflow through that heater (because it's blocked from above) the heater will overheat and trip the thermal overload.

It could melt the wiring inside the heater.

It could start a fire

and overheat the bookcase.

You only have two choices. Remove the bookcase or abandon the heater and disconnect it and install baseboard on another wall

Jean-David Beyer

Ignoring the code and fire-hazard questions that I am not competent to address, if you love books, you will not keep them on a shelf above an oven or an electric heater. It is bad for books.

Larry Weingarten

Hi @kaycee , How difficult would it be to raise up the bookcase roughly four inches? I'd look at doing that, adding drywall under the case and then adding sheet metal, sloped the right way to encourage warm air flow. Also, the metal you have in front looks like it will seriously obstruct air flow. I like the idea of louvers or simply welded wire mesh.

Yours, Larry

Icarus

A piece of tin or steel, screwed on the bottom of the bookcase with a small airspace, would probably keep the bookcase cool. That said, I probably would abandon the electric there all together from a risk point of few.

Icarus

mattmia2

I'd move the baseboard heater to another wall or in front of the bookcase. It is easy enough to reroute the wiring in conduit under the bookcase.

cement backer board is rated for reducing clearances. drywall is not. still do not do it. you can only install electric baseboard heater according to the manufacture's instructions, there is no code section addressing reducing its clearances.

TAG

Had electric baseboard in a ski house I built -- that stuff gets hot. I can't believe 4' is code -- having that small an air gap above.

That setup is a disaster waiting to happen -- I think the newest stuff has an overheat sensor ... the old stuff did not. I know because in the bathroom it always concerned me with towels falling on them.

JUGHNE

A solution would be to use electric radiant cove heaters.
They work well on an inside wall and could be connected above the existing wall tstat. The are wall mounted less than a foot from the ceiling. More length is required, 8-9' long.
No furniture or drape issues.
There are houses here that use nothing else.

Icarus

Replace it with an oil filled baseboard unit, or a electric hydronic. Operating temp is significantly lower.

https://www.homedepot.com/p/Cadet-SoftHeat-71-in-1-250-Watt-240-Volt-Hydronic-Electric-Baseboard-Heater-EBHN1250W/306652812

vibert_c

@Kaycee said “what is the worse that could happen if it doesn't work”....

You will likely ruin your valuable books at the least, likely have a serious house fire.

Congratulations for thinking out of the box! Where did you get this idea from, the nice people on the web?

Electric baseboard heaters running on 230 volts Ac and six feet long usually are rated at 1500 watts. (250w per foot) The rising temperature of the air that is supposed to circulate through it reaches in excess of 250°F sufficient to leave traces of cooked dust on the adjoining wall above it for at least nine inches. This in my opinion is unhealthy to say the least.

I have over the years compensated for this extreme temperature as follows:
When I am restricted to the so called “bang bang” ON/OFF cycle of the power, I have rewired the baseboard to half voltage. Ie 230 down to 115 volts. (simply switch the red wire in the panel to neutral, label it white, attach black lead to a 115 single pole breaker) That reduces the power to 1500/4 = 375 watts. The result is you can comfortably place your hand on the heater or dry your socks on it.

If this reduced heat is not sufficient to sustain the heat in the room then I suggest you abandon your concept entirely.

Realize cooked dust is not what you want in your lungs during the cold winter months; think steam mate!

vibert_c

EdTheHeaterMan

Ya can't change the laws of thermodynamics and Ya Can't Fix STUPID
Remember when the car 12-volt adaptor was originally designed for a cigar lighter. Ya pushes it in and electricity makes the coil glow RED. That RED was hot enough to light up the combustible things called cigars and cigarettes
Now that same stuff... Electricity is makin' the coil in the baseboard heater git hot. Without proper airflow across the heater, the coil in the baseboard heater can git RED. The same RED that made the cigar or cigarette git fired up.

Them books you got there, I'm a-thinkin' thay is made of the same stuff the cigarettes is made of... PAPER. I'm a-thinkin' that isn't a good idea to put that paper so close to the RED in the electric heater. But what do I know?

Ya cant fix STUPID.

EBEBRATT-Ed

Moving the baseboard out in front of the book shelves is probably the best bet