Over the course of our work, we are frequently asked by clients how they can reduce their energy use at home or the office. Of course, installing a solar photovoltaic system is a great way to offset energy demands but there are lots of other ways to reduce electricity consumption. Here we’ll address a handful of strategies to decrease power consumption, lower energy bills and be better stewards of the planet.
YOUR HVAC SYSTEM
Here in Florida, air conditioning accounts for a significant amount of all energy consumed – more than 40% of home energy use. Thankfully, today’s HVAC systems are vastly improved in terms of energy efficiency from what they used to be.
According to the Department of Energy, “The most efficient air conditioners use 30% to 50% less energy to produce the same amount of cooling as air conditioners made in the mid-1970s. Even if your air conditioner is only 10 years old, you may save 20% to 40% of your cooling energy costs by replacing it with a newer, more efficient model.”
The Seasonal Energy Efficiency Ratio (SEER) rating, which ranges from 14 to 25, starts with the system’s output and divides it by the energy the unit consumes. In Florida, with its ongoing heat and humidity, a higher SEER rating is recommended.
Air filters impact the quality of air inside of a home as well as serve as protection for the HVAC system (a clogged filter will increase energy consumption). Before purchasing air filters, you’ll want to check their Minimum Efficiency Reporting Value (MERV) – the scale ranges from 1 to 16, with superior filters earning the highest rating.
Other more recent advancements include programmable thermostats, which enable you to program the temperature a little higher for when you’re at work or on vacation, or cooler when you’re home. Taking things even a step further are smart thermostats, WiFi-connected devices that automatically adjust heating and cooling temperature settings in your home for optimal performance and to match your preferences. (You can also adjust the thermostat remotely, through your smartphone.) While the cost for the latest generation of smart thermostats is around $250, they can save you around 15% of your AC electrical costs and they are very convenient to use. And – let’s face it – they are cool-looking, too.
SWITCHING FROM INCANDESCENT LIGHTING TO LEDs
According to the Department of Energy, “Lighting accounts for around 15% of an average home’s electricity use, and the average household saves about $225 in energy costs per year by using LED lighting.” Light emitting diodes (LEDs) are a type of solid-state lighting – semiconductors that convert electricity into light. They cost a little more than double what an incandescent bulb would cost but they use 90% less energy and last 25 times longer.
Most LED bulbs can last up to 25,000 hours – even if you ran one 24 hours a day, seven days a week, you’d only have to replace it every 15 years. (The lifespan of an incandescent bulb is around 1,000 hours.) LEDs are available in 40W, 60W, 75W and 100W and come in a wide variety of colors.
According to ENERGY STAR – the program run by the U.S. Environmental Protection Agency (EPA) and U.S. Department of Energy (DOE) that promotes energy efficiency – nine out of 10 homes in the U.S. are under-insulated. It asserts, “… Homeowners can save an average of 15% on heating and cooling costs (or an average of 11% on total energy costs) by air sealing their homes and adding insulation in attics, floors over crawl spaces, and basements.” In addition to saving you money, proper insulation makes it easier to maintain a comfortable temperature regardless of the conditions outside.
It is important to note the R-value for insulation. The R-value is a measure of insulation’s ability to resist heat traveling through it. R-values, which can be improved by adding more layers, vary depending on a region’s typical temperatures. In most of Florida, R-38 tends to be the industry standard, requiring about 10” of thickness for cellulose or 16” of fiberglass. R-values are highest for blown-in insulation, with fiberglass installation blankets next and foam board insulation coming in last.
It’s beneficial to insulate any area where heat and cold could accumulate and impact your home’s temperature and energy efficiency, such as crawl spaces, the garage, water heater and pipes, and ceilings.
Weather stripping is a simple and relatively low-cost way to improve the energy efficiency of a home by reducing air leaks through the moving parts of doors and windows. According to ENERGY STAR, the installation of weather stripping can save you up to 20% on heating and cooling costs.
Before grabbing the caulk gun, though, you might want to have a professional do a “blower door test.” Home energy professionals use a blower door as a diagnostic tool to discover how much air is entering or escaping from your home as well as to determine recommendations for the best sealing approach.
According to the Office of Energy Efficiency & Renewable Energy (an office of the DOE), “Heat gain and heat loss through windows are responsible for 25%-30% of residential heating and cooling energy use.” That means if the windows in your home aren’t energy efficient, your heating and cooling unit(s) are being forced to work harder to keep your home comfortable.
Not only do window films reduce around 80% of the sun’s heat coming through your windows, they also protect your furniture, fixtures, carpets and floors from harmful UV rays. If you’d really like to geek out on the subject, feel free to learn more about the following energy performance characteristics: U-factor, solar heat gain coefficient, and air leakage.
Replacing your windows is another way to improve energy efficiency. Triple-pane windows can be up to 20% more efficient than double-pane windows and up to 50% more efficient than single-pane windows. But the more panes there are, the more expensive they will be; it could take as many as 15-25 years for triple-pane windows to reduce the energy costs enough to pay for themselves. They are also heavy – you need to make sure your home can handle the extra weight.
As you may guess, white or light-colored roofs reflect heat rays from the sun, keeping the attic and rooms below it cooler during warm weather (i.e., most of the year in Florida). Light-colored roofs are sometimes called “cool roofs” as they keep the attic and rooms below it cooler during warm weather (i.e., most of the year in Florida) because they serve as a reflective barrier that reduces solar heat gain on the building. Believe it or not, cool roofing methods can make a difference of 20-40 degrees, which significantly reduces the load on your HVAC system as well as your energy costs. Our rooftop installation crews (including myself) have personal experience with this and can attest to darker roofs often being so hot you cannot touch them during summer afternoons (I have literally melted my shoes on some darker metal roof systems!) while white and lighter colors are just slightly warm – often just a few degrees above air temperature.
The Solar Reflectance Index (SRI) calculates a roof’s capacity to “refuse” solar heat. A cool roof combines high reflectivity (the ability of a material to reflect solar radiation from its surface back into the atmosphere) and high emissivity (how efficiently and quickly a surface releases heat and returns to its normal temperature). The higher the SRI value is, the greater ability the coating has to reject solar heat absorption and keep your house cooler. An SRI value closer to 0 indicates a darker or black surface while a value closer to 100 indicates a brighter or white surface.
For every 10% increase in roof reflectance, your heating/cooling costs can drop two cents per square foot per year. It may not sound like a lot but it adds up very quickly – especially when you consider how warm Florida is for most of the year.
HAVEN’T HAD ENOUGH YET?
Please don’t hesitate to contact us if you have any questions about how you can reduce your energy use at home or the office or wish to discuss any of the points listed above!