ELK-6021 Window Sensor Question

[Eric2XU]

I am building a new home and they put in double hung windows. Its unclear to me how to use a single sensor to protect the entire window. I have a ELK M1 Gold I am bringing from my old home. 
 
Has anyone ever installed a ELK-6021 sensor and if so can you share a photo of how you did it? Its says not to mount to metal so what would I mount the part that has the battery too that will still make contact with a on glass sensor? Is there totally a different way I am not thinking of to do it? Drywall is up now so hard wire is no longer an option and at $50 a sensor I dont want to double down on each window. 
 
Last question, anyone know if any ELK reseller does bulk discounts, I have over 30 windows, at retail that's over 1,500$ just in wireless sensors.  
 

 

[RAL]

I am building a new home and they put in double hung windows. Its unclear to me how to use a single sensor to protect the entire window. I have a ELK M1 Gold I am bringing from my old home. 
 
Has anyone ever installed a ELK-6021 sensor and if so can you share a photo of how you did it? Its says not to mount to metal so what would I mount the part that has the battery too that will still make contact with a on glass sensor? Is there totally a different way I am not thinking of to do it? Drywall is up now so hard wire is no longer an option and at $50 a sensor I dont want to double down on each window. 
 
Last question, anyone know if any ELK reseller does bulk discounts, I have over 30 windows, at retail that's over 1,500$ just in wireless sensors.  

 
The usual way of protecting both sections of a double hung window is to mount the transmitter on the top of the lower sash, and the magnet on the bottom of the upper sash.  That way, if either section is moved, it will trigger the sensor.
 
You can see an example in this Honeywell video.
 
Are your window sashes constructed from wood or metal?
 
Most authorized Elk dealers sell at list price, or close to it.  There are some unauthorized dealers that sell a bit below list. But Elk may refuse to honor the warranty on items purchased from those sellers.   You'll need to decide if the lower price is worth the risk of possibly no coverage if you run into problems.  With a large number of sensors, you might take that chance since you could still come out ahead even if you have to replace a few and pay out of your own pocket.