Few things are as annoying as a broken air conditioner during a heat spell. But in the middle of the summer, you might have to wait days for a technician to show up to fix your unit. And that’s not to mention the money that you’ll have to dish out for repairs, often in the range of several hundreds.

Fortunately, fixing a broken central or window-mounted air conditioner can be a DIY project.. Below are a few of the best do-it-yourself air conditioning repair and maintenance tips. While these won’t apply to every single solution, they will come in handy for most problems related to “low cooling” and “no cooling.” They will also help keep your air conditioner in good repair so larger, more expensive problems, do not occur in the future.

1. Change Your Filters

Dirty air filters kill the efficiency of air conditioning units. During the summer, it is important to change yours once per month. AC air conditioners are rated according to their MERV (minimum efficiency reporting value). This ranges from 1 to 12 for home air conditioning units. Select a filter with a higher number as these provide better filtration and use less energy.

2. Fix Leaks

Leaky ducts are another common problem with air conditioning units. Window-mounted ACs, in particular, loose air through poor sealing. Find leaks by holding a stick of incense near the place where the AC unit and the window frame meet. If the smoke blows around, there is a leak. Tape and foam work well to fix leaks, as do caulking and sealant.

3. Clear Space

Central air conditioning units usually have a compressor and condenser located outside of the house (close to the foundation). Make sure there is at least 24 inches of clear space in each direction from these parts. Spend a little time trimming back nearby shrubs, tall grass, and leaves to increase your unit’s efficiency.

4.  Keep Sunlight Away

Direct sunlight is particularly bad for the health of your AC. You can extend the life of your unit and reduce repairs by keeping the blinds or shades down during the day (or installing it in an area that does not get direct sunlight). Turn overhead fans on to help circulate the cooled air.

5. Consider a Programmable Thermostat

Blasting cool air all day is just not good for your AC. You are better off turning it off (or at least down) when you are away from the house. This will increase the life of your unit. A programmable thermostat is a great way to do this. It will automatically keep your AC turned on when you are home and turn it off when you go to work. A programmable thermostat will also help reduce your monthly energy bills.

Our favorite programmable thermostat is the Nest Thermostat. Check out our review of it here.