You should start out in your "back yard" and just do what is average for that area. 

Not sure if there was an generic industry number people used.

I don't know of another industry that creates the tremendous rewards real estate investing does, but you have to work for it.Here's wishing you tremendous real estate investing success!

Thanks @Brian GarrettI was thinking the same thing but was not sure what industry trends were. 

We both have average credit, just over $10k and both properties are single family, about $70k.

My husband and I are newbies and are making an offer on a commercial/industrial property in Wisconsin (Appleton, near Green Bay / Oshkosh) this week.  

Average is probably 7.5-8%.

@Nimster Win Would urge you to never disclose your private details on the Internet.The restaurant/cafe industry has one of the highest failure rates of any industry.

What is the average number of addresses on the list?

@Harrison CookYour post kindles lots of questions.In the "good old-days" most heating systems were vastly oversized for the building they were heating - energy was relatively cheap, insulation was non-existant to poor ... so it was easier and safer to {drastically} oversize.Today, while energy {in North America}  is still relatively cheap for the moment,  we have a much better understanding of how to make buildings more efficient {though you might not think so looking at the construction industry in the U.S.A. and Canada}  and there are often more cost-effective measures than simply replacing an old, over-sized heating plant with a new, over-sized heating plant.You really need to - or at lease should -  perform a heat load analysis to properly size your heating system, a component of which, is determining the rate of heat loss of the building envelope.