High efficiency isn't necessarily better for everyone????

10 years ago

My heat broke and I have struggling with new system choices. Since energy efficiency nowadays is so much emphasized, I THOUGHT replacing the old 8 seers 3 ton unit with 16 or higher 3 ton is going to use less energy in the future than before. However, after reading about "load calculation," my 1700 sq ft house may not need a 3 ton higher seer unit, especially with my life style.

My house is always very humid even in winter, now rh about 60%, because I use the washer to wash sweaters, wool sucks, and down coats, and AIR DRY them in winter. I boil water all the time and almost merely steam almost all foods. I set lower temperature in winter and higher temperature in summer, compare with most of Americans. In winter, our heat almost never is running at night, because we love tuck ourselves in a heavy comforter, which makes our sleep better (more like hibernation).

So.... I would say that higher seer units are more efficient for more extreme climates, while I live in GA. Summer and winter here is so mild. The usage of the unit is much less. A higher seer unit, like 16, would not energy saving anymore in my house condition, right???

What seer would you recommend to me, living in a pretty much maximum energy saving environment already?

Although I haven't had someone to do the load calculation yet, do you think it's more sensible to go for a 2.5 ton rather than a 3, due to humidity level being so high in my house?

Thanks a bunch

Comments (9)

mike_home
10 years ago
How type of heating system do you have and what fuel do you use?

What are you annual costs to heat and cool your house? How much is the cost of electricity and the heating fuel you use?

I thought the summers in Georgia were hot and humid, but you say they are mild. What is a average high temperatures in the summer?

If you provide more information you will get better guidance.
chueh
Original Author
10 years ago
LOL... mike_home. yep, I guess that everybody's point of ivew of comfort is different. To me, GA is very mild, although people say that it's humid and hot. I lived in Miami before, so I have the comparison. Comparing to the north states, the winter is so mild.

August temp: between 90-95 average....
December + January: between 20-55...

Unlike many people who set their t-stat at 72 degree for winter, while wearing a t-shirt. I feel better to wear layers in winter, so I don't like to feel the EXTREME changes between indoors and outdoors.

We use electricity for the entire house, no gas or other fuel system.

I am not sure how to separate the cost of merely heat and AC from the annual electricity cost! I have never calculate the kwh of the HVAC. Anyway, here is the total usage annually, if that would help you to figure out to answer your question for me:

Jan 800 kwh
Feb 1000
Mar 880
Apr 450
May 450
Jun 650
Jul 580
Aug 790
Sep 570
Oct 400
Nov 570
Dec 1000
* This past December reached up to 1200, because the heat pump was acting up and iced up while it was running for no heat.....

See... our electricity usage is not much compared to most people's. So....high energy efficient wouldn't help, right?
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mike_home
10 years ago
The decision to invest in more efficiency comes down to how long is the pay back period. Your energy usage does not seem high, and your electric rate is probably low to average, so the pay back period may be very long.

Just a few things to consider. For AC condensers the minimum SEER rating allowed by federal law is 13. A SEER rating of 15-16 is considered the best value in terms of initial cost and energy savings. The low end equipment may have a 13 SEER rating, be built of cheap materials, and have very basic features. You are better off buying quality equipment. Usually it also means better efficiency.

The size should be determined by a load calculation. If the 3 ton worked well, then it is probably the right size. If you want better humidity control in the summer, I suggest getting a 2-stage condenser. These only come in whole ton sizes and usually have higher efficiency ratings.
chueh
Original Author
10 years ago
OK....So...Mike_home, even for my low electricity usage and life style, 15-16 is still the best value, due to they are "better built" even with a reputable manufacturer like Carrier?
mike_home
10 years ago
I would avoid buying the bottom line units.

FYI - The SEER rating is determined by the combination of the condenser, coil, and handler. It also changes when you move up and down in size with the same equipment.

Don't get so focused on buying a SEER rating. Stick with the one of the better brands, get it sized correctly, and find a contractor who can do a good installation.
chueh
Original Author
10 years ago
OK thanks...
joe_mn
10 years ago
You have a heat pump now? Maybe in my world I assume all heat pumps are high efficiency? You also say you have all electric service so you have an electric water heater? Seems to me that is a huge energy device.
pbx2_gw
10 years ago
Unlike many people who set their t-stat at 72 degree for winter, while wearing a t-shirt. I feel better to wear layers in winter, so I don't like to feel the EXTREME changes between indoors and outdoors.

Isn't this the truth?! Wear some layer & lower it down to 68 & people would see savings in their bills.
countryboymo
10 years ago
Well if you step up to a decent efficiency (15) seer that has good ahri numbers that match you will probably get a txv as standard equipment instead of a piston orifice which helps cut humidity which will make whatever temp is comfortable in summer now feel cooler possibly allowing a higher set temp. It will also probably come with demand defrost which will save you more in winter than you might think if you use a heat pump. If it is above freezing my system rarely goes into defrost unless something is falling from the sky and its below freezing. A builders grade 13 seer will defrost on a timed system defrosting after every 30/60 or 90 minutes of accrued run time and some run for a full 10 minute cycle. Most systems have oversized heat strips so every defrost burns $$ in comparison to none.

I think you would be happy either way.. The better system will pay you back with better comfort and quieter operation with a probable longer lifespan and better warranty.

It seems either way a new system is going in. Don't forget to calculate the cost differential between the options.