For HVAC systems, efficiency is critical for measuring performance and can be used as an indicator of a problem. Your equipment has a rated efficiency at the beginning of its life and this drops over the years with use. Understanding how it all fits together will help you make decisions about whether to repair or replace your equipment. It will also help you to decide whether to spend extra for the most efficient model.
Here are the basics of HVAC efficiency that you need to know.
Furnace efficiency is represented by its AFUE, Annualized Fuel Utilization Efficiency. This tells you how much energy is converted into heat for your home over an annual basis. It’s calculated by measuring the output energy and dividing it by the input. High efficiency furnaces have efficiencies ranging from 95-98% while regular efficiency furnaces average 78-80%. It’s important to note that this is an overall efficiency and the actual efficiency varies during use at part load conditions and during startup and shutdown. In any case, your aim should be for the higher efficiency model.
Air conditioning and heat pump efficiency
You may notice a number called the EER (Energy Efficiency Ratio) or SEER (Seasonal Energy Efficiency Ratio) on your air conditioner. This is the ratio of the output cooling divided by the power required to provide that cooling. Since cooling is measured in BTU/h (British Thermal Units per hour) while input power is in Watts, EER is not shown as a percent the way efficiency is usually stated. The SEER is a measure of the efficiency over an entire season and takes into account various conditions that the unit could be exposed to while EER gives the rated performance at an outdoor temperature of 95oF.
The higher these numbers, the better the efficiency and the less electricity you consume trying to cool your home.
Why it matters
As mentioned, these efficiency numbers tell you how much heating and cooling you get for a given energy input (either through burning fuel or through electrical work). It can help you carry out the cost-benefit analysis of upgrading to a new unit, whether you’re at the end of your existing HVAC equipment lifespan or just concerned about lowering your energy consumption.
If you need to discuss ways to improve the efficiency of your HVAC equipment or are ready to replace it with an upgraded system, give us a call. We can also help you make the right decisions about whether it’s time to change your equipment.