My desk gets really hot.
November 12, 2009 8:21 AM   Subscribe

Thermodynamics-filter. I own a large metal desk that I keep pushed up against my window. Underneath my desk top (clearance of a few inches) is my furnace. Whenever I turn the furnace on, the desk top heats up very quickly. I do not want to move my desk if at all possible. (great view). Could I make a heat shield for the underside?
posted by Damn That Television to Home & Garden (13 answers total)
 
You could probably tape or attack via magnet and hot glue some foam board from an art-supply store. It's cheap, and has good insulating power, but it might look awkward, depending on how your desk is shaped.

Failing that, maybe a shrinkwrap window insulation kit could work. It'd be less visible if you do a careful job.
posted by mccarty.tim at 8:28 AM on November 12, 2009


What about a deflector?
They also have plastic scoop shaped ones that you can get at any building store.
posted by bonobothegreat at 8:32 AM on November 12, 2009


When you say furnace, do you mean one of those below-window radiators? Like this?

Regardless, I don't think you'd have any problem attaching some kind of insulation to the bottom of the desk - either mccarty.tim's suggestion of foam board or a small piece of insulating foam from a hardware store should work just fine.

A word of warning, though: try to figure out how hot it gets. Having paper-covered foam board near a very hot surface (the furnace) could be a fire hazard. I personally think that using some kind of flame-retardant insulation would probably be best, but would likely be more expensive.
posted by malthas at 8:39 AM on November 12, 2009


In the Uk you can get dense foam insulating board about an inch thick that has foil on one side. I'm just trying to find a picture of what I mean...
posted by twine42 at 8:46 AM on November 12, 2009


Something like this. Over here I'd try a builder's merchant or a Home Depot type place.
posted by twine42 at 8:50 AM on November 12, 2009


Overall answer: yes you can make a heat shield for your desk and it will help, but...

What type of furnance?
How much do you want to spend?
How much clearance do you have?

Just as a first pass I would recommend a low emissivity cover on the bottom of the desk, but it really depends on how far you want to go with this. The reason your desk heats up quickly, other than that it is right over the furnace and hot air is moving up, is that it conducts well. The approach recommended above, and by others approaches this by saying don't let the energy in to the bottom of the desk (are there metal sides on this desk?). If you are ok with part of your desk being warm and just want a cooler top surface you could put an insulator between the top surface and the rest of the desk (if taking the top off is an easy thing that is...).

Fair warning, your feet are going to be warmer.
posted by Feantari at 9:27 AM on November 12, 2009


Similar to some earlier suggestions: there are heat deflectors for radiators that I assume you could attach to not just the wall but the underside of your desk.
posted by lakeroon at 9:40 AM on November 12, 2009


Response by poster: Thanks for the help so far dudesss. Here are a few more details:

The desk is basically a giant metal rectangle, two small legs with a long stabilizing foot off each. The legs would also have to be covered to prevent conductivity of heat, but they're much smaller/easier to cover than the underside.

The furnace is a natural gas number, a little like this: http://www.houseneeds.com/shop/images/empire_dv40eb.gif

I have about 3 inches between the top of the furnace and the underside of the desk. If I need/want to, I can increase this a few inches (adjustable desk).

I'll spend up to 100 for a perfect solution, or 50 for a reasonable solution.
posted by Damn That Television at 10:35 AM on November 12, 2009


If the "furnace" is actually a steam radiator or one of those flat panel radiators, it will be heating up your metal desktop mainly by convection (unless the underneath of the desktop is painted a dark colour, in which case it might be absorbing radiant heat). If you put a desk fan underneath your desk, arranged to blow air across the radiator and set on low so it's not annoyingly noisy, most of the hot air should end up moving out sideways instead of drifting upward, so it will still heat your room but won't cook your desktop on the way.
posted by flabdablet at 10:38 AM on November 12, 2009


On lack of preview: I would personally not work at a desk that had an unvented natural gas heater operating underneath. I'm just not that fond of gas fumes. But if I absolutely had to, I'd certainly be deflecting its outlet air sideways with a fan. Not only would that limit how much it heated my desk, it would reduce the concentration of combustion products I spent all day breathing in.
posted by flabdablet at 10:42 AM on November 12, 2009


It's difficult to see how deep this heater is exactly, but I would consider pulling the desk from the wall a few inches (the depth of the heater) and installing some kind of mesh shelf between the desk and the wall. It will allow the warm air to rise and catch whatever migth fall off the back of the desk. Another solution would be to pull it off the wall and install a lip on the back edge of the desk surface to stop anything from falling. The key idea here is to allow the warm to rise...
posted by bluefrog at 1:47 PM on November 12, 2009 [1 favorite]


It looks like the hot air vent is at the bottom of the heater. If this is the case, it may be easier to port it away from the desk and off to the side. You could probably use dryer vent hose and duct tape for this, provided that you don't decrease the flow rate.
posted by kuujjuarapik at 2:17 PM on November 12, 2009


You could try putting some material with a high thermal conductivity in between. That is, rather than some sort of insulation, you could see if you could mount a thin sheet of aluminum or something like that, with a small air gap between the aluminum and the desk bottom. The idea is, the furnace heats the aluminum, and the aluminum conducts the heat away laterally instead of heating the bottom of the desk.

I can't really imagine an under-desktop geometry that would be simple to make, though, since the aluminum would have to extend out past the edges of the desk and radiate the heat out there instead of just becoming an intermediate heat source to the desk bottom.
posted by ctmf at 6:02 PM on November 12, 2009


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