Searching for Balance springs fo heavy sash windows

We can supply balances that are rated for heavier windows, but stained glass admittedly might be pushing the limits of what we can do.

Before we say anything for sure, I'd like to review exactly what we're dealing with. Would it be possible to get the exact weight of the sash? Can you also show me some photos of the balance itself? At this stage I am not yet certain if we even have a configuration that's compatible with this window, even ignoring weight capacity.

Once I have a better idea of what kind of system you need I will be able to tell you for sure if we can help.

Thank you so much! This is a huge help. Based on the information I see here, you should be able to get one of our standard balances to work without issue. 30 pounds is definitely on the heavy side but it's still a common enough sash weight.

Let's talk about the length, first. You said that your original balance is 24" long, but that your channel length is 26". Can you confirm what size you need, exactly? Changing the original glass out with stained glass shouldn't have affected the length of the balance itself. You should still be using a 24" version. I'd like to be 100% sure what size that is before we proceed.

Next, I want to discuss the Series; this is determined by the combination of nylon fittings. I've narrowed it down to two possibilities: either our Series 380 or Series 385. The only difference between them is the depth of the bottom shoe. Granted, this is a very slight difference, but it is still important. I recommend reviewing the diagram below to confirm the better option.

Comparison of the S380 and S385 balance shoes.

Lastly, we need to look at the most important detail out of all of them: the spring calibration. This will be different depending on length, but you have a few options available to you.

Looking at the 24" balance, you would pick either our 2360 option (27 through 30 pounds) or the 2365 option (30 through 34 pounds). Assuming that your balance is exactly 30 pounds then theoretically either stamp would work. You may want to triple check just to be sure. It helps to get the weight down to the ounce so that you can pick accordingly.

Looking at the 26" long balance, you could use either our 2560 stamp (28 through 30 pounds) or 2565 option (30 through 33 pounds). Same rules apply here, though I highly recommend checking the length of the metal channel to ensure what size you need.

Thanks for clarifying. It sounds like you want to stick with the 24" length, then. Don't worry about the size of the track it goes into. As for the window not opening all the way, that is also normal. You don't want the window to open up those last few inches in most situations.

It also sounds like the Series 385 is the best pick, so the S385-24 is my official recommendation.

Concerning weight, it's ultimately up to you. Just note that it is possible to have a balance that is too strong; if the spring it over-calibrated then you will have trouble closing the window, and it could drift up on its own. At this stage you will just have to use your best judgment. Since the sash definitely seems to weigh around 30 pounds then the 2360 or 2365 is going to be what you want to pick from.