Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
Read thread "trane unit installed in 2010" this is the problem we don't want you to end up with
Thanks JT. The way you express your concerns makes it easy for me to hear your advice, and I do appreciate it, believe me!
I just read that thread. Also watched all the Comfort Institute videos. They're very easy for lay people like me to follow, and don't use gibberish to talk down to us like some folks in this forum. I am even more committed to insuring Manual J is done properly after I commit to my contractor of choice, and am willing to accept that the 3-ton XL20i may be the proper size.
Thanks again!
From an energy rating perspective,
My guesstimate of your FPL bill is in the range of ...
( based on Your descriptions in comparison to
what I spend on my residence_)
January _70
February _ 70
March_ 80
April __ 90
May __ 110
June __ 140
July ___ 170
August _ 180
September 160
October _ 140
November_ 100
December _ 80
May - October = $900
of which ~ $500 or 5000 kW is for cooling which equates to about 1,500 hours run-time.
I suspect it may be as much as $40 per month more for June - September because set-point of 75'F is rather low.
YOUR FPL data is easily retrieved from www.fpl.com
http://www.fpl.com/residential/index.shtml
How much my $/month is on the low side depends on the amount of glass and orientation SW/ SE and any overhangs which are likely mimimal for Florida Space Coast.
+ the refrigerant charge may have been significantly affecting the performance recently.
You should definitely appreciate your L O W Relative Humidity and associated comfort level.
KiloWatts used = ~ 10 X $ / month
Last edited by dan sw fl; 08-22-2012 at 04:13 AM.
Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
If you are spending as much as $800 for the FL long cooling season, you may see an annual $300+ savings optimistically with a high end 2-stage
Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
Dan, I hope I can save a LOT more than $300 annually!
FYI, the 75 degree setpoint on my t-stat is misleading. Using a cheap electronic thermometer from Lowes i've discovered that the temp at the t-stat is actually 77 degrees when it's set to 75. I've adjusted the t-stat upwards each year since I moved in in Dec 2009, in an attempt to save money. The current setting is about as high as I can go and still remain "fairly" comfortable. You can see the results in the FPL data below. T-stat was set at 72 (74 actual temp) in 2010. I upped it to 74 (76 actual) in 2011. Finally upped it to 75 (77 actual).
Note the *** for the August amount. This is when the compressor fell over and leaked all my freon, but kept running until it was fixed and the leaking accumulator was fixed.
I did the FPL online energy survey a couple of weeks ago, and it told me that my heating and cooling costs are 75% of my bill!
Month KWH Amount
August 2012 2360 258***
July 2012 1868 200
June 2012 1741 187
May 2012 1138 117
April 2012 1119 114
March 2012 637 66
February 2012 551 58
January 2012 795 81
December 2011 579 62
November 2011 811 84
October 2011 1489 160
September 2011 2081 230
August 2011 2064 228
July 2011 2203 244
June 2011 1749 191
May 2011 1438 154
April 2011 870 90
March 2011 420 47
February 2011 723 75
January 2011 1137 117
December 2010 580 61
November 2010 980 99
October 2010 1847 199
September 2010 2197 240
[QUOTE=Florida Joy;14034571]Dan, I hope I can save a LOT more than $300 annually!
I did the FPL online energy survey a couple of weeks ago, and it told me that my heating and cooling costs are 75% of my bill!
Since my May - September bills total around 1200, I'd expect to save around 50% of 75% of that amount, or about 450 a year. Is that reasonable?
In Home now: 10 SEER 3.5T 2400 CH @ .15KW =1512
Wants: 20i 17.5 SEER (actual seer on this unit, 17.75 17.5) 4.0 T 2400 CH @ .15KW = 980
May save 450-550 a year
Always here
I prefer not to get into a discussion in this thread regarding load calc and tonnage requirements for replacing the 3.5 ton in my home. Also, I'm not sure of the math involved in plugging in a different SEER/tonnage to come up with cooling cost.
So, just to compare, can you tell me what the savings might be if I end up going with the 3.0 ton XL20i at 19.0 SEER?
Savings from longer run times is stricky to estimate. But a fair estimate is an additonal 10-15% savings going from 3.5 ton to 3 ton. So cutting your bills nearly in 1/2 is a fair estimate. You'll save proportionally more in cooler month than hotter months. Although when it's above design conditions on the hottest days, you save even more because it will fall behind a little firther cutting energy use and on those days it my run in either low or high stage almost continously except for a few short periods in the early morning, so you'll really notice an improvement in humidity control. You may even end up setting the thermostat a few degrees armer because it's control humidity so much better with longer run times. See how you get that domino effect? Longer run times means your removing more humidity and are more confortable at a high indoor temprature which in turn means you cna keep it warmer, save money and need less capacity and have more even temperatures, less air noise and more comfort. THe unit will be nearly silent in low stage at most registers.
motoguy128 - I was looking for energy star to caculate my summer (6 month) energy cost for the 19 SEER in the same manner as he did for the 17.5 SEER. I don't have access to the "table" or computation formula he used to calculate 10 SEER versus 17.5 SEER based on the actual KWH data I provided in my post.
As far as saving proportionally more in the cooler months, that's just not possible because I turn the air off and open the windows during the day in the late fall and early spring and only run it at night if needed to sleep. I rarely use heat in the winter, maybe once or twice in January if it gets down to freezing. You can see from the billing history I posted that it's the 6 months of summer I'm concerned about.
I doubt if I'd set the t-stat up a notch with a new system. The RH inside with my old system never goes over 40% and I don't know of ANY new system that advertises less than 50%.... more than likely humidity would be in the 55-65% range, so I'd likely have to set the t-stat DOWN a notch, if anything.
Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
[QUOTE=dan sw fl;14037671]I had hopes of having an extra hundred dollar bill for my piggy bank in each of the summer months, based on "purported" savings that one of my Trane estimaters claims the folks 2 doors down are getting since he installed a 15 SEER in that house. They're renters and I don't know them, so I'm a little shy to knock on the door to confirm what he said.
Oh well, give me at least half that in savings and a reasonably priced system built to last 20 years or more and I'll be happy. HA, HA, I know that's asking a lot!
.105? I used a larger number, gotta link to .105
Always here
Sure you can in 2 ways. 1) 40% RH @ 75F is great, 33%RH @ 77F is even better in terms of energy savings but is equally comfortable. 2) if hte sytme cna reach 40% RH sooner, then more capacity will go into sensible cooling than latent. A smaller coil with the same load, will drain sooner and more water than a larger one.
Right now my house is at 43%RH @ 74F upstairs and 33%RH $77F downstairs. Both are comfortable, but downstairs has lower proportional heat loss. Which is good since it's 10 SEER and oversized.
You're in Iowa? How far is that from the Atlantic Ocean and what's the average RH and dew point outside your house in June, July and August? In my neighborhood the average RH is 90% with an 80 degree dew point and average temp of 88-90.
My 12 year old, falling apart Rheem maintains inside RH at 40%, but I haven't seen any new equipment that claims to be able to match or beat that.