In no particular order, here are some key things to look for as you select an architect for your renovation project. You should decide on the relative priority of these issues before interviewing architects.
Fees for professional design services have a huge range. The methods of determining fees usually fall into two main groups: percentage of construction cost and hourly. Architects whose fees are figured as a percentage of construction cost will typically fall in the 5% to 8% range. The problem with this type of fee structure is that there is a small, though not insignificant disincentive for the architect to promote cost effective design solutions. Though the architect will bill progressively through the project, it is unlikely that there will be a "refund" at the end of construction.
The hourly rate structure, however, provides little incentive for the architect to complete the drawings in a timely manner. A good compromise is the "hourly-not-to-exceed" rate structure. The architect estimates the amount of time it will take to complete the drawings and provides the client with a "cap" on the fees. This way the Client has a good sense of how much design will cost, and is still protected from unexpected design fees.
Some architects who have significant experience in renovation projects will bid by the square foot. Such a bid will probably fall in the $1.50 to $3.00 per square foot.