There are government standards for measuring heating and cooling equipment. The most common being SEER which stands for seasonal energy efficiency ratio. The higher the SEER rating the more efficient the system is. Currently the minimal efficiency rating for manufacturers in the U.S. is 14.2 SEER. But there are systems available that rate as high as 30 SEER. Typically, the higher the SEER rating is the more expensive the equipment is.

Properly maintaining your system is the only way to extend the life of your equipment and proper maintenance will help your system operate more efficiently as well.

When a system has too much capacity the equipment tends to satisfy the thermostat very quickly. This often results in the system not adequately removing moisture from the space and can lead to problems due to high humidity.

A good rule of thumb for determining whether an air conditioning system is performing correctly or not is the 20 degree rule. This states that if a system is cooling properly you should be able to measure a 20 degree of drop of temperature across the evaporator coil. This can be measured by taking temperature readings at the air intake (return air) opening, and at the supply registers.

My favorite answer to this question is: Whatever temperature you are comfortable at. The whole point of having an HVAC system is to keep you more comfortable than you would be without it. Of course, some of us have to make decisions between comfort and expense. Setting your thermostat higher during the cooling season will reduce your utilities in the summer and vice versa during the winter.

Programmable thermostats automatically change your temperature settings based on a schedule that you can create. For example, if you go to work Mon. – Fri. at the same time everyday you may decide that you want to set your temperature settings higher or lower than you need them when you are at home, and then schedule the program to bring the unit back on in time to return the temperature to your desired setting by the time you return. Doing this can reduce your utility costs. There are various types of programmable thermostats. Some will allow you to schedule each day individually, others only allow you to schedule certain blocks of time. You should check with your HVAC contractor to make sure you get one that meets your needs.

There are a variety of types of air filtration systems used in HVAC systems. How often yours will need changing or cleaned will vary upon what type it is as well as how much particulate is being filtered out of the air in your house. If you are using a standard 1” media filter (the most common) we recommend using a pleated media filter with a Merv rating of 10-13. On this type filter you can generally hold them up to a light and see how restricted they are or how full of dust they are. If you think they are at least 30% restricted it is time to change them. I would recommend to begin checking them weekly. The more history you have in determining how quickly yours are becoming restricted will help you determine how often you need to change them.

The capacity (or tonnage) requirements for a system are determined by doing a load calculation on the conditioned space. Some of the primary items used in load calculations will include the area that is being conditioned, the type of building materials used to create the space, and the insulation value (R-value) present on the space. There are also different weather zones that should be considered, as well as things like the amount of shading from the sun, or exposure to lake winds.

In most residential HVAC systems we recommend having preventative maintenance performed once in the spring to check the cooling system, and once in the fall to check the heating system.

System cycle times will vary depending on how much load is present, and the type of equipment you have. Variable speed equipment (equipment that ramps up capacity as load increases and reduces capacity as load decreases) will have extremely long cycle times which may sound bad. People think long cycle times equal higher utility bills. But with variable speed equipment the exact load is matched with capacity so the system is actually running extremely low amperages when the load is less than the maximum capacity required. This results in significant reductions in electricity usage.

If you HVAC system has stopped working you should check your thermostat to see if it is turned on. Also, check it to see if it has batteries that may have expired. Many thermostats will have a blinking battery indicator to let you know it is time to replace the batteries. You can also check to see if there are breakers that have tripped. It is alright to attempt to reset the breaker (this is done by pushing the breaker completely in the off position and then switching it back to the on position). This may restore lost power to the equipment and allow it to run, however, in many instances there is an underlying problem that will need to be diagnosed and repaired. If the breaker trips again you should definitely have your system checked by a professional. Repeatedly resetting the breaker without having it serviced may result in damaging your equipment.

The cost of replacing your equipment will vary greatly. There are many factors such as, capacity, type of equipment, location of equipment, accessibility of equipment, efficiency of the new equipment, etc. Most service companies will give free quotes so it is usually best to have your HVAC contractor come out and give you an estimate.