Understanding SEER Rating

In the middle of the real estate boom, the United States Department of Energy mandated making the minimum SEER rating of our HVAC systems 13 SEER or greater . This would go in to effect in January of 2006, and many builders and HVAC companies were warehousing older 10 SEER units for cheaper installations and parts. I was a real estate agent at this time and the decision was not popular with many of my colleagues. “It’s just going to make homes more expensive” and “my old unit works just fine, why does the government have to get involved” were the most common complaints. We didn’t like it, but honestly I don’t think any of us could have explained what a SEER rating even meant!

SEER stands for Seasonal Energy Efficiency Rating and is an average of the unit’s cooling efficiency. Simply stated, the higher the SEER, the more the efficient the unit. As a mathematical formula it would read:

Total cooling output over the cooling season / total energy input over the cooling season

Luckily many of the older lower SEER units installed before 2006 are long gone. The average lifespan of an AC unit is 10-15 years, but it is possible that if you are still running one of the old ones it could have a SEER rating of about 6. It is not uncommon today to find units operating at a SEER as high as 27 and while the upfront cost is higher, you will pay less over the course of its lifetime.

Below is a comparison of the cost of operating a 6 SEER unit compared to a 13 SEER unit. Both are 3 ton units (36,000 BTU) running 8 hours per day. We’ll say that the cooling season is 4 months long and the average utility rate is .10 cents per kilowatt hour.

6 SEER

36,000 BTU/hr. x 976 hours / 6.0 SEER = 5,856,000 watts / 1,000 (to convert to KW) = 5,856 KW x $0.10 = $585.60 per year

13 SEER

36,000 BTU/hr. x 976 hours / 13.0 SEER = 2,702,769 watts / 1,000 (to convert to KW) = 2,703 KW x $0.10 = $270.30 per year

This is an annual savings of $315.00 per year, or $4725.00 over its average 15 year life span. Rebates from your local power companies will often bring the cost of the higher SEER units more in line with the minimum SEER models, so be sure to check before purchasing.

Even if you are not ready to replace your older unit, you might want to consider having your duct system tested. 20-40 percent duct leakage is not uncommon and a homeowner repair is not difficult. Doing this now will ensure that you are milking every last ounce of cool air from your existing system. It is likely you will begin to save money without replacing your existing system! 

Should I turn the lights off when I leave the room even when using CFLs?

This is a question that I am asked on almost a daily basis and quite honestly I had no answer. I researched the question online, and below is a link to the best explanation I discovered.

http://greenbuildingelements.com/2008/04/07/when-to-turn-off-fluorescent-lights/

Basically the article says that there is no need to worry about how many times CFLs are turned on and off. If you are going to be away from the fixture more than 5 minutes, turn it off. There is concern that this will shorten the lifespan of the bulb, but it is not an important one.

One of the aspects of turning off lights that is not discussed in this article is the fact that when the light is off no electricity is being used. I know this seems like an all too obvious observation, but think of it this way; most of the electricity generated in the United States is done so by burning coal. For every kilowatt NOT used, less (or no) coal is burned. Even if you shorten the life of the bulb by repeatedly turning it off and on, it will still last longer and use less electricity than a normal incandescent bulb. When it is off it uses none!

Invariably, when CFLs are mentioned, the conversation will end up in a discussion of the hazards of mercury. CFLs do contain small amounts of mercury and special care is needed when disposing of them. But one of the main contributors of mercury in our environment is the burning of coal. I can’t give hard numbers, but I would imagine it would take more than a few broken CFLs to come anywhere near releasing the amount of mercury that a power company coal stack emits in an hour! When you leave the room, turn off the lights!

Energy improvements on an older home: where to begin

             Energy improvements on an older home: where to begin

Before the fuel crisis of the 1970s most Americans never thought twice about their home’s energy consumption. Many lived in older homes that had been retrofitted with electricity, indoor plumbing and forced air heating and cooling, and how efficient these systems were was less important than the fact that were simply there. Efficient and installed were synonymous!

The air conditioner brought an explosion of growth to the southern half of the United States that had once been declared “too hot for civilized people” to live year round. These systems were installed in homes that were not designed for such modern equipment and the results were mixed. Basically as long as the system was blowing cool air the house was cool. These homes were just not good at holding the cool air. So let’s discuss a few ways to bring these homes up to reasonable energy consumption levels. 

Below is my priority list, but it is okay to skip around some if you can’t afford the next measure.

1.     Seal all balloon framed walls and attic penetrations (plumbing, wiring, HVAC).

2.     Seal and insulate attic hatch.

3.     Seal and insulate knee walls in attic area.

4.     Insulate attic to R-30.

5.     Seal and insulate all forced air duct work.

6.     Install vapor barrier in crawlspace.

7.     Seal all plumbing and wiring penetrations in crawl space area.

8.     Caulk and weather strip around doors and windows.

9.     Install bath fans and range hood.

I would consider this list of priorities as a baseline before I purchased any type of energy saving appliances. Of course if the appliances or HVAC system need replacing before you complete the list, do so with Energy Star models. 

I would also consider having a blower door test conducted by a qualified individual before attempting any work. By doing this problem areas can be identified and large amounts of air infiltration/exfiltration can be eliminated. It is a good idea to have the testing done by an impartial person and not a company that wants to sell you the improvements.