Is this going to be a problem
 

I don't like the DVR being on top of my TV, it looks ugly because of the size of the box.

So I put it on the bottom. But it has top and side vents.

Is this going to be a problem?

http://img.photobucket.com/albums/v3...agon/tvset.jpg
http://img.photobucket.com/albums/v3...agon/space.jpg

Doubt that it'd be a problem. If I knew the ambient temperature of your space, I'd have a better answer. For example, I have a late 70s Zenith system 3 color solid state 19" running as my basement set. With the oil-fired steam boiler it easily gets to ~80ish degrees F down there (or more), since it's a large house to heat in winter.
It has proper ventilation but still runs warmer than it would upstairs where it's 72.

I'd take 4 stacks of two cassette tapes (in their containers) placed at the corners and use them to give a better gap for ventalation.....just to be safe.

I would just check to see if there is heat coming from the DVR after some good use. You would not want to excessively heat your TV from the DVR.

On the other hand, I suspect that heat rising from the TV could raise the temperature of the DVR ( if placed on top of the TV) considerably. Perhaps you could try to measure the temperature rise?

jr

My guess is this is probably better for the DVR than on top of the TV - in fact, the TV probably helps draw air through the DVR. Anybody in the house smoke? Or do you have some incense? You could check the airflow.