When your brand-new A/C system suddenly breaks down, your A/C warranty is the only thing between you and a $1,000+ repair bill. Unfortunately, it's easy to void your warranty without realizing it, which could lead to a wallet-lightening surprise you don't expect. Here are a few common ways you could accidentally stumble into this nightmare scenario.

1. Ignoring Regular Maintenance

Regularly scheduled maintenance ensures that your A/C system operates reliably at its peak performance. Keeping up with regular maintenance also prevents small A/C problems from snowballing into major issues. Your A/C warranty requires you have your system maintained at least once a year—otherwise, your HVAC manufacturer may refuse to honor your warranty on the grounds of poor or lax maintenance.

2. DIY A/C Repairs

A DIY repair sounds like a great way to save money on A/C repairs and most A/C systems have components that can be safely serviced by the average person. For major repairs, however, you'll need an HVAC technician on hand who has the tools and the expertise to provide professional air conditioning repair services.

There's plenty that can go wrong if the average do-it-yourselfer attempts a major A/C repair, which explains why most HVAC manufacturer warranties prohibit DIY repairs.

3. Repairs Made With Non-OEM Parts

It's not uncommon for HVAC technicians to make repairs using aftermarket or so-called "off-brand" parts due to their lower cost when compared to original equipment manufacturer (OEM) parts. However, there are a couple of downsides to this approach.

While some aftermarket parts meet or even exceed OEM quality, others may be made from lower-quality materials or feature an inferior design to the original component. OEM replacement parts are not only made to function exactly like the original counterparts, but they're also made with higher-quality materials.

Additionally, most HVAC manufacturer warranties prohibit using aftermarket parts due to their unknown quality and reliability. To preserve your warranty, you'll need an HVAC tech dedicated to using only OEM parts for their repairs.

4. Forgetting to Register Your A/C

If you're like most homeowners, chances are you've haven't paid much attention to the registration card that came with your new A/C system. Failure to fill out that card could prove a costly mistake when you really need your warranty most.

Most HVAC manufacturers require you to register your A/C system either by mail (by filling out and mailing in that aforementioned card) or by following the online link to the appropriate registration form. Either way, registering your new A/C system lets you take full advantage of its warranty if you ever need it.

Time is of the essence, as most manufacturers only give you 30 to 90 days from the date of installation to register your A/C equipment.