wheel size confusion My bike is a Genesis Day One 2011 originally Alfine 8 hub, only thing is I bought it as a fixie without the hub. I wish to purchase an Alfine 8 hub and wheel and revert it back to it's Alfine 8 glory. Current wheels are 29". 
I was thinking of only purchasing the rear wheel complete with hub...it is all I need. Tho, I am encouraged to buy a pair of wheels rather than just one rear as it is easier to sell a pair than just one rear wheel (the ones I would take off).
The only thing is, that wheels available within my budget are both advertised as described below.

My Q - 
On the website the rear wheel with the Alfine 8 hub is described as 28" with dimensions of 622x19.
And the front wheel is described as 29" with dimensions 622x19.

What is the difference? Dimensions are the same! Could I use these two wheels together with the same tyres I already have?

Some say 29"and 28" are the same just marketed differently for different bikes, others say they are different...what it is then?

Any help and clarification welcome!!!!!!!!!
Inch measurements for wheels are really just labels that often refer to the diameter of the rim plus a nominally sized tire rather than an accurate measurement of the rim diameter.

The 622x19 spec is what you need to pay attention to. 622 is the diameter of the rim bead seat in mm. 19 is the inner width of the rim in mm.

Look at your tires, if they are marked 'ISO 622' or 'ETRTO 622' or '700C' (an French system label that is the same as ETRTO/ISO 622), then they are 622mm diameter.

You can measure the inner rim width of your rims. They don't have to be exactly 19 mm for your current tires to fit. A tire of a given overall width will fit on a range of rim widths.