Saving Energy: Understanding Energy Ratings

Understanding energy ratings

If you’ve ever shopped for a new air conditioner, furnace, or even a window unit, you’ve probably seen energy rating data listed somewhere on the product. Knowing what those numbers mean, and how to compare them, can save you a lot of money over the life of your equipment.

Making sense of the numbers

Ratings help you make smart choices 

Energy ratings were established to provide a baseline for comparing heating and air conditioning equipment based on the energy it uses to keep you comfortable. In a sense, you can think of energy ratings like miles-per-gallon in a car.

The more gasoline it takes you to go one mile, the more you’ll spend for every mile you need to travel. So if you’re looking at a large SUV that gets 15 miles per gallon, you know you’ll need to plan a larger fuel budget every month than if you’d chosen a subcompact or hybrid car that gets 38 miles to the gallon.

What the ratings mean for your home

With home heating and cooling equipment, the efficiency numbers tell you how much energy you’ll have to spend to get the same performance out of similar products.

Ratings are different for each type of heating and cooling equipment, simply because of the energy source used to power it. In other words, you can’t use the same rating to compare a gas furnace to an electric heat pump, because they don’t use the same type of fuel.

However, when you understand the numbers behind the ratings, you can get a good idea of how much money you’ll spend to run your equipment, whether it uses gas, electricity, or both.

SEER, for rating electric cooling

SEER is one of the most common rating systems for home cooling equipment. It stands for Seasonal Energy Efficiency Ratio, and it gives a pretty good indication of your energy costs because it measures performance over an entire cooling season.

To calculate SEER, you simply take the total cooling output that the equipment will generate over the summer, measured in British Thermal Units (BTU), and divide it by the total amount of energy you’ll have to expend (and pay for) during the same time period.

What you’re really measuring here is how much cooling power the unit will provide, and how much it will cost you to enjoy that cool comfort. The Lennox® XC25 is currently the most precise and efficient air conditioner you can buy*, offering a SEER of up to 26.

Federal law currently mandates a minimum SEER of between 13 and 14, depending upon where in the country you live, and any air conditioner over 14.5 SEER can be eligible for ENERGY STAR® qualification, meaning it’s a smart choice for energy-efficient cooling.

AFUE, for rating fossil-fuel furnaces

AFUE is a different way to measure efficiency, because it deals with a different type of fuel. The AFUE of a furnace, which stands for Annual Fuel Utilization Efficiency, is a measure of how much heat is generated over the course of the heating season, compared with how much fuel is burned.

AFUE is a fairly straightforward number. The higher the number, the more heat you will actually feel for a given amount of natural gas or oil burned. A furnace with an AFUE of 80 will turn 80% of its fuel into useable heat, while wasting about 20% of its fuel through either air leaks, inefficient burners or a less-advanced design.

On the other hand, a furnace with an AFUE of 95 will convert 95% of the gas or oil it consumes into useable warmth. Any furnace with an efficiency of 90% or higher is considered high-efficiency.

The Lennox SLP98V furnace currently offers an AFUE of 98.7, meaning it converts 98.7% of its fuel into useful heat for your home. With less than 2% fuel waste, it’s a very efficient way to weather the winter.

*The most precise and efficient air conditioner and heat pump you can buy (XC25/XP25)
Efficiency claim based on comparison of air conditioning and heat pump products’ SEER as published in AHRI (January 2013). Actual system combination efficientcy may vary; consult a Lennox Dealer or AHRI for exact system efficiencies. Precision claim based on the cooling capacity range of the XC/XP25-036 units as compared to equivalent-sized competitive variable capacity compressor units.

HSPF, for rating electric heating and cooling

In the simplest terms, an electric heat pump is an air conditioner that can run in reverse. During the summer, it moves heat out of your home into the atmosphere. Then, during colder weather, it reverses the process and draws latent heat from the outside air into your home.

Since it doesn’t use fossil fuel, AFUE really doesn’t apply. So heat pumps actually have their own comparative efficiency rating, known as HSPF, or Heating Season Performance Factor. This is a measure of how efficiently an electric heat pump can warm your home when it’s in heating mode, over the course of an entire heating season.

HSPF is calculated by dividing the unit’s heat output over the course of the season by the amount of electricity required to produce that heat. Anything over 8 is considered high-efficiency, and may be eligible for utility rebates or tax credits.

When shopping for a heat pump, it’s important to remember that since it uses electricity to heat and cool, it will have both a SEER and an HSPF rating since it runs during multiple seasons.

The Lennox XP25 heat pump currently offers a SEER of up to 23.5, and an HSPF of up to 10.20.

Thermostat advice from the professionals.

Let Betlem's experts help you connect with your thermostat.

As the brains of your heating and cooling system, the thermostat can have a huge effect on energy efficiency and comfort.  Eric St. John, Residential Manager of BETLEM Residential, weighs in on thermostats, and the advantages you’ll enjoy with a programmable model.

The heart of your system.

“The thermostat controls every other part of your system,” says St. John.  “It’s your point of contact.  So it’s important to use a thermostat that can give you maximum return on your system investment.”

For that reason, St. John recommends a programmable thermostat.

Coordinated with your schedule

Programmable thermostats work by reducing system use when your home is empty, so you don’t waste money on heating and cooling an empty home.  They do this by running according to a schedule that you program based on the hours that you are home.

“Changing your heating and cooling settings for different times of day can help you save money,” he says. “ A programmable thermostat makes those changes for you automatically, synchronizing your heating and cooling with your life.”

Set for savings

To program a thermostat for the best mix of comfort and energy efficiency, St. John recommends the following settings.

For summer:

• Set your thermostat for 78 degrees when you’re home
• Set it for 85 degrees when you’re away
• Set it for 82 degrees when you’re asleep

For winter:

• Set your thermostat for 68 degrees when you are home
• Set it for 60 degrees when you are away
• Set it for 60 degrees when you are sleeping

During the transitional months of spring and fall, St. John recommends setting the thermostat based on personal preference, using summer and winter’s settings as a guide.

There’s more to it than temperature

While temperature is the main factor affecting your comfort, St. John says that it’s not the only one.

“Humidity plays a huge role in comfort.  You know how the weather report says it’s 90 but it feels like 100?  That’s humidity.  Moisture levels in the air affect the way the air feels on your skin.”

If your thermostat offers individual humidity control, it can change how your air feels without big changes in temperature.  Which means more energy-efficient cooling and heating.  Systems with variable speed can also help control humidity levels by drawing air across the coil slowly to remove more moisture on startup.

Find your perfect thermostat.

BETLEM Residential currently offers several different models of programmable thermostat:

View BETLEM's Programmable Thermostats

Get comfortable with a home energy audit

How can you identify and prioritize home upgrades that will also reduce your energy bill and make your home more comfortable? With a do-it-yourself home energy audit!

Like the home energy audits offered by many utility companies, the DIY audit starts with a simple walk-through of your home to assess energy wasters and improvements to eliminate them.

Here are three important places to start:

1. Inspect your cooling/heating system

Heating and cooling accounts for nearly half your home’s energy usage. Improving efficiency here can make a noticeable difference on your monthly energy bill.

• Your HVAC system should be inspected at least once a year. Your Lennox dealer can check and clean your equipment to help control energy usage.
• If you have a central heating and cooling system, the filters should be checked monthly – especially during high-usage seasons – and replaced as needed (at least once every three months) to keep the system working efficiently.
• Check ductwork for streaks of dirt that indicate air leaks. These should be sealed with duct mastic. Insulate ducts or pipes that extend through unheated spaces.
• If any HVAC unit is more than 15 years old, a newer system can greatly reduce your energy usage and lower your energy bill.

2. Assess your lighting

Lighting makes up about 10 percent of your electricity costs.

• Examine the wattage of your light bulbs. If your lamps are using 100-watt or larger bulbs, consider a 60- or 75-watt replacement.
• Install compact fluorescent bulbs in areas where lights are left on for hours at a time.
• Move lamps away from your thermostat. The heat produced by traditional light bulbs can be sensed and may force your air conditioner to work harder.

3. Eliminate drafts

Reducing air leaks or drafts can reduce your energy usage by 5 to 30 percent, according to the U.S. Department of Energy and make your home much more comfortable.

• Look inside for gaps along the baseboard or edge of flooring and where the walls and ceiling meet.
• Look outdoors at exterior corners, where siding and chimneys meet and areas where the foundation and exterior brick or siding meet.
• Rattle windows and doors: Any movement means possible air leaks. If you can see daylight around a window frame or door, there is a leak that can often be fixed by caulking or weather stripping. Check storm windows for a tight fit. If new, high-performance doors and windows are too expensive, low-cost plastic sheets can be installed over windows to block air.
• Plug or caulk air leaks from or around electrical outlets, switch plates, attic hatches and window-mounted air conditioners.
• If you’re having trouble locating air leaks, you can try this simple building pressurization test:
  • Close all exterior doors, windows and fireplace flues
  • Turn off all combustion appliances, including gas-burning furnaces and water heaters.
  • Turn on exhaust fans in the kitchen and bath.
  • Dampen your hand to feel any cool drafts, or burn an incense stick to look

Get smart about home energy efficiency

Did you know as much as half the energy consumed in your home goes to heating and cooling?

If you haven’t replaced your HVAC system with a high-efficiency, ENERGY STAR® qualified model, you’re probably spending significantly more on home utility bills—up to 20% more if your heat pump or air conditioner is more than 10 years old, and up to 15% more if your furnace is more than 15 years old.

Here are a few more steps you can take to increase energy efficiency and savings in your home:

Close the envelope

Insulating and sealing the exterior of your home, often referred to as the “envelope,” can help keep air from leaking into the home from the outside, or vice versa, helping you to save up to $200 per year on home heating and cooling costs.

Seal the ducts

Duct sealing can save up to $120 per year in coastal areas, and as much as $190 if you’re inland.

Install a programmable thermostat

An ENERGY STAR qualified programmable thermostat can save you up to $100 per year in coastal areas and over $150 inland. Lennox’ icomfort Wi-Fi Touchscreen Thermostat lets you set your home’s temperature to save energy from anywhere in the world, using a smartphone, tablet or laptop. It also offers a live weather forecast and automatic updates for added convenience.

Add a power strip to areas with high-traffic devices

Using a power strip in home offices or entertainment areas can help you save up to $100 annually on your utility bill.

Replace old windows

Installing new, ENERGY STAR windows in place of old windows can save you between $150-500 in annual energy costs.

Install a new shower head

A new 2.5 gallon-per-minute shower head can help you tuck away an extra $145 a year in electricity costs, in addition to saving you 5 gallons of water per shower.

Add a ventilation fan

Installing a ventilation fan to control moisture, mold and mildew growth in the bathroom can save you up to 60% more energy than standard models when using an ENERGY STAR qualified model.

Replace incandescent lightbulbs

Substituting CFL bulbs for just five of your highest-use fixtures can save up to $70 per year on home utility bills.

Replace old appliances with new, high-efficiency models

For the greatest savings, choose ENERGY STAR approved models: They’re up to 40% more efficient than standard models. Here’s a breakdown of how much you’ll save by replacing your home appliances with an ENERGY STAR approved model:

• Dishwasher—Save up to $40 per year on utility bills when replacing a 1994 or older model.
• Refrigerator—Save 20% per year on home energy costs. Unplugging an extra refrigerator in the basement or garage can equate to an additional $300-700 per year.
• Washing machine—See approximately 30% in energy savings per year compared to standard washers. Full-sized washers save 10-20 gallons of water per load.
• Clothes dryer—Save more than $135 a year if your dryer is over 10 years old.
• Water heater—Save up to $80 per year on gas bills; larger families will see even more savings.

For more energy-saving tips, take a virtual home tour with ENERGY STAR’s Save Energy @ Home tool.

Source: EnergyStar.gov.