Do you tend to ignore your home's heating system when the weather is sunny and the days are warm? While summer may still be in full swing, fall is right around the corner. Unpredictable temperatures in many parts of the country can make for some chilly fall nights, so you may need to fire up your furnace sooner than you expect.

Unfortunately, neglecting your heating system during its off-season can lead to some unpleasant surprises when temperatures drop. If your furnace has been out of sight and out of mind for the last four or five months, then these three crucial maintenance tips can help ensure that the first cold evening doesn't leave you shivering in bed.

1. Learn About Your Filter

No maintenance checklist would be complete without advice on replacing your filter. However, blindly replacing your filters every month or two can waste money. Filter replacements vary by size and type, and your home's HVAC system may have a thicker filter that requires less frequent replacements. Instead of immediately running out and buying a new one, take some time to learn about your filter.

Thickness is usually the primary determining factor for filter replacements, with 5" filters lasting up to a year in relatively clean environments. Try to determine when you last replaced your filter and compare that to your recommended replacement interval. If in doubt, replacing your filter before the heating season begins is often a smart move.

2. Perform Basic Cleaning Tasks

Cleaning your furnace is often a good idea, although it can be more challenging with modern, high-efficiency units that have sealed combustion chambers. In general, you can usually remove the furnace cover (it may pop off or there may be screws holding it in place) and gently vacuum the interior. Although your furnace should have a door safety switch, you should still cut power to your furnace first.

When cleaning the unit's interior, always go as gently as possible and avoid touching or disturbing any internal components. Now is also a good time to look for signs of damage to wires or any indications of rust. Water generally shouldn't enter the interior of your furnace, so corrosion may indicate a more severe issue.

3. Schedule Your Check-Up

Routine filter replacements and interior cleaning are a good way to keep your furnace running well, but you'll still need a professional to perform additional maintenance tasks. Depending on your furnace's model, a professional may need to inspect your furnace's safety sensors, lubricate parts, or even check and replace the belts on your house blower.

Fortunately, fall is an excellent time to schedule this appointment. You'll have plenty of flexibility to choose a time that works for you, allowing you to complete your annual heating maintenance and inspection long before it's time for your furnace to really get to work.