Working from home - utilities cost?

[blorg]

I do some extra "nixer" work (IT) which I perform from home. This is secondary to my main PAYE employment which I don't do from home. Can I claim a percentage of utility costs (light/heat/phone) against my income from this work? Percentage of rent? If so, are there any Revenue guidelines on this and what records need to be kept?

 

[jpd]

Be careful about doing this. I believe that you could end up with a part of your home being assessed for CGT in the case that you sell it.

 

[blorg]

I'm renting, so that isn't a concern. Any other ideas?