Harcar residential window

We'd be glad to assist. Can you send a photo of the lift (balance) that you need? Try to find another balance in a different window in order to send a photo of the balance hook, too.

Thank you for the detailed images. We have known most Harcar windows, such as yours, use the Series 380 balances. These balances include a 19-005 top and 15-005 bottom balance fittings. Look over the balalnce shoes and match them up with yours. Do they look the same? More importantly, are our measurements compatible with yours? If so, you will need the S380-24 with a 2820 option to accommodate your stamping of "28B". And for the other balance with a "28C" will use a 2830. 

Normally a window company does mix spring weights on the same sash. You may want to weigh the sash to see what would be the correct spring weight to use. Please review our media guides for more help.

Being that someone had previously worked on the windows, we feel more confident that you can use S380-29 channel balance. Don't fret on the 9/16" and 1/2" metal channel. Everyone's tape measure can be read differently on the same part. Thank you for the sash weight of 20 lbs. Now we can suggest the spring weight as (2830) for a sash weight 16-23 lbs. and yes use the same spring weight for each sash.