There is quite a bit of information available online about eCommerce conversions rates. According to a ton of sources, average visitor-to-sale conversion rates vary from 1-3%. This does not mean the Furniture conversions will be the same. The bigger problem is that visitor-to-sale conversions are not a good data point to use to measure or tune your eCommerce business.

All business have some unique friction factors that will affect your final conversion rate. It's very important to understand each of these factors and how to overcome them. The best way to measure and optimize is to take a conversion funnel approach. Once you have defined your funnel you can optimize each conversion rate to better the total effect.

For example:
Top of the funnel: - All web site visitors, 100,000 / month
First conversion: View a product page, 50% of all visitors
Second Conversion: Add to Cart, 10% of people who view products
Final Conversion: Complete Checkout, 80% of people who put items in a cart

In this example we see that only 10% of people who actually view products put them in to a cart, but 80% of those people purchase. If you can figure out why visitors are not adding items to their cart and fix the issue to increase the conversion rate, revenue should increase significantly because of the high checkout rate.

You can use free tools like Google Analytics to give you a wealth of information about your site visitor and their behavior or there are some great paid tools as well.