Discount Filters has two strong sitewide discount codes running right now. The featured 35% off voucher at the top of this page gives you the biggest single saving on any purchase, and the Labor Day Sale code also delivers 35% off sitewide until September 8. Only one code works at checkout, so you'll want to compare which gives the better result for your basket.
Small baskets under $100. The 35% off sitewide code is your best choice here. On a $50 order, that's $17.50 in savings. The specialist furnace and AC filter code (30% off) will only beat it if you're specifically buying those products, where it saves $15 on the same $50 basket—still less than the full sitewide rate.
Medium baskets from $100 to $300. Again, reach for the 35% off code. A $200 order saves you $70. The furnace and AC code stays at 30%, so it would only save $60 on that same basket.
Larger baskets over $300. The 35% off sitewide codes remain your top option. On a $500 order, you're looking at $175 in savings compared to $150 with the 30% furnace and AC code.
Buying furnace and AC filters specifically. You've got a choice. The 30% off furnace and AC filters code is dedicated to this category and saves you a full 5 percentage points more than the general 20% off all filters code. However, it still trails the sitewide 35% codes. Compare at checkout and pick whichever gives the bigger dollar saving for your exact products.
Buying limited filters and accessories on sale. The extra 20% off limited filters and accessories code applies here, but only on items already marked as limited. This will rarely beat the 35% sitewide offer, so use it only if you're buying exclusively from that limited range and the math works out better.
Orders under $50 with no specific category focus. The 10% off code is your minimum safety net, saving you around $3 to $5 depending on basket size. But if you can stretch to $50, free shipping kicks in automatically—a saving worth considering against a small percentage discount.
Orders $50 and over. Free shipping is yours automatically with no code required. Layer that against your chosen percentage discount code for the full picture of your total savings.
Remember that only one discount code applies at checkout, so you need to enter whichever code gives you the larger dollar saving for your specific items and basket size. Check the math before you complete your purchase.