Bathroom on main floor vs upstairs by bedrooms?

[Jeremy Engelin]

We recently purchased our new home and are in the process of renovating our old home to turn it into a rental property.  The house was built in 1880 so much of the layout was done as needed over time and as a result it didn't function well.  Due to issues with plumbing we needed to redo the single bathroom (its a 3 bedroom house) anyway.   We are trying to decide if we turn the small office upstairs into the bathroom or keep it in the current location off of the kitchen/dining area.   Moving it upstairs has a higher cost due to the location and re-piping but would allow us to extend the small kitchen and dining area a bit.   My wife is sold that families looking to rent a 3br home with kids would want the bathroom upstairs near the bedroom, which is probably right, but I'm not sold that it would be a deal breaker or worth the extra $3000 in costs. 

Ultimately, my concern is trying to not necessarily maximize the rent but try to keep turnover low.  I'm wondering if anyone has experience with bathrooms upstairs vs. downstairs and whether it has any real impact on rent-ability or tenant turnover?  In either case they would have a brand new bathroom with clean/updated fixtures.  Rent's in our area are not super high and the house is not really large, it is only around 1200 SQ FT, and with heat included I was wanting to get around $1200 per month.  Heat is a big deal in the cold upstate region, and by including it I'm trying to ensure no frozen pipes and protect my investment.  We had an ultra high efficiency furnace put in a few years back when we were living there so the yearly heating costs are fairly low.