As we come into the holiday season and homes are putting up decorations and lights (you are using energy efficient lights – right) it can be a time of holiday bliss. Then it can turn into holiday regret when the electric bills start rolling in (see, told you, should have used energy efficient lights). The holidays shouldn’t be the only time to be looking at energy efficiency however.
Almost everyone in the United States is familiar with ENERGY STAR®. We see it everywhere. What many people are not aware of is that ENERGY STAR has a special category that recognizes the most efficient products within a product category for that year. Each year ENERGY STAR provides product performance criteria in order to be recognized. In the ventilation fan category, specifically bathroom and utility room fans they must operate at an 85% higher efficiency level than a standard model. This is measure in CFM/Watt (cubic feet per minute of air the fan moves divided by how many watts of energy needed to run the fan). ENERGY STAR has set the criteria at greater than or equal to 10 CFM/Watt. That means that a 100 CFM fan cannot use more than 10 watts of energy to operate.
Great, but what does this mean in real world numbers? Lets first look at the efficiency number of two 100 CFM fans. A standard – builder grade fan operates at about 1.4 CFM per watt. The Air King model D4S, an ENERGY STAR Most Efficient 2017, operates at 15.6 CFM per watt when set to 100 CFM. Now lets take a look at what that means from an electric standpoint. For our purposes, we are going to say the exhaust fan runs for a total of 4 hours a day. The builder grade fan operating at 72 watts for 4 hours needs 288 watts per day. Times that by 365 and you get 105-kilowatt hours per year. Using that same equation the D4S only uses 9.3-kilowatt hours per year.
When needing to replace a fan, energy efficiency is a great starting place. Other factors to consider are sound levels, duct size, fan size and of course price is always going to play a part.