This is a guest post by Chris Long, a store associate at a Chicago-area Home Depot. Chris also writes on HVAC topics for Home Depot's website. HVAC and furnace maintenance are among the many areas for which Chris provides advice to homeowners.

Just because we're nearing the end of the summer, that doesn't mean you're in the clear in terms of taking care of your HVAC unit. Indeed, by making a conscious effort to maintain and regularly check in on your air conditioning unit or furnace, you can save a bundle throughout the year!

So, when was the last time you changed your HVAC filter? Did you know that this is the perfect example of how spending a little bit of money on the front end (purchasing replacement filters on a regular basis) can really add up from that point forward?

Consider this: when your AC has a cleaner filter, the system doesn't have to work so hard to suck and cycle the air throughout your home. Not only does this preserve the condition of the internal components (like the compressor and motor, etc.) which helps to extend the life of your unit, but it also greatly improves the air quality within your house (which can even be worse than the outside air when you have a funky filter).

Of course, cleaner air means more money saved across the board so make sure to clean or swap out your filters more often (as frequently as once a month) if you live with the following:

• Allergies
• Asthma or other respiratory conditions
• Smokers
• Pets

Here are a few more money-saving tips that homeowners can implement to cut costs around the house.

Install a Programmable Thermostat.
One of the largest sources of wasted energy and inflated utility bills comes from an HVAC or furnace that is constantly running. A simple solution (again, it will cost you more upfront but you will realize savings in the long run) is to install a programmable thermostat that monitors your home's temperature and operates the rising and dropping temperatures more consistently.

When you are not at home, there is no reason to run the AC at your optimal temperature. Especially in the heat, that could mean your unit runs all day! With a programmable thermostat, you can input temperatures and times when you will be home and away and the system will make sure to shut off when you leave and start a gradual cool down (or heat up) before you arrive home.

Weatherize your Doors and Windows.
Gaps in windowsills and door frames are little spaces that can cost you big time in wasted energy. Fortunately, most of these are easily fixed with simple DIY remedies.

• Apply caulking around your window casings and door jambs.
• Attach weather-stripping under and around doors.

Other money-saving hints include:

• Whenever possible, leave your windows open  intentionally and use fans in lieu of turning on your HVAC.
• During the brightest parts of the morning and late afternoon, leave curtains or window treatments open to allow in natural lighting (and turn off lights inside), but close them during the hottest parts of the day to keep cool air inside and heat from the sun outside.

What easy cost-cutting tricks do you have for other homeowners looking to pull back on bill-spending?

Image thanks to Home Depot.