Btus ratings??!!! Towel radiator question

[somuchtodo]

Me again; thought I would post a separate message for a separate subject so you could see what it was about - hope that's OK!

So, in our main bathroom and (tiny) ensuite we plan to have towel radiators as the source of heat.

We've specified a 1800mm x 500mm one for the 407 cu ft main bathroom, and a 800mm x 500mm one for the tiny 164 cu ft ensuite. (both chrome; I know white gives better output, but you know how it is!)

My question is; we're also going to have summer electric elements in them; the bathroom suppliers have suggested a 300 watt dual energy element for both - is that enough?

Also, is it right that you multiply the room cu ft by 5 to get the required BTU rating for the radiator?

Thanks again!

 

[gas4you]

Never heard of that. L x W X H and number or outside walls, whether cavity insulation or not, thats the only method I know of to work out heat loss

 

[giblets]

The summer elements are only supposed to dry the towels in the summer not cater for the heat loss of the room.

Be wary of the outputs quoted for the heating output from the water side - gets greatly reduced when covered with towels.