Pros & Cons of Trane XL20i Versus XL16i Heat Pump

[dan sw fl]

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

FPL= $0.105 / kW-Hr
$ 1512 * .105/.15 = $1058
$980 * .105 /.15 =__ $686
_________________ $372 which is in mid-range of $340 - $420

[Florida Joy]

[QUOTE=dan sw fl;14037671]

$1,200 * 0.7 = $840 A/C ... = $140/ month
__________ .. $360 Normal use = $60/ month

40% - 50% = $340 to $420.

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!

[energy star]

.105? I used a larger number, gotta link to .105

[motoguy128]

Definitely a FALSE PREMISE in This Situation:

It's impossible to improve upon 40% Relative Humidity.!.!!..!!!

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.

[Florida Joy]

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.

[dan sw fl]

.105? I used a larger number, gotta link to .105

Yes, stop by & I'll show you my FPL electric bill.

Or see post # 188 for kw & $. = $00.105 kW/hr

[dan sw fl]

double - erratic PC.

[dan sw fl]

Right now my house is at 43%RH @ 74F upstairs and 33%RH $77F downstairs. .

77'F @33% R.H.

How do you get L.A.T. < 47'F?
_ When is the last time your hygrometer was calibrated?

http://www.thermalinc.com/math/wetbulbcalc.htm

[Florida Joy]

.105? I used a larger number, gotta link to .105

This is the info directly from my August FPL bill:

kWh used 2360
Customer charge: $5.90 per month
Storm charge 2.78
Gross receipts tax 6.08
Franchise charge 14.59
**The electric service amount
includes the following charges:
Fuel: $92.49
(First 1000 kWh at $0.033430)
(Over 1000 kWh at $0.043430)
Non-fuel: $135.94
(First 1000 kWh at $0.051840)
(Over 1000 kWh at $0.061840)

[beenthere]

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.

90°F drybulb with a dew point of 80°F is less then 73%RH.

[dan sw fl]

Central and South FL is typically > 90% R.H. from 3 AM to about 9 AM.

90% R.H. ..=.. Dew Point is 2'F less than Dry Bulb.

Obviously, opening windows in early morning is NOT an Optimum cooling option for nearly 5 months.

[motoguy128]

77'F @33% R.H.

How do you get L.A.T. < 47'F?
_ When is the last time your hygrometer was calibrated?

http://www.thermalinc.com/math/wetbulbcalc.htm

The humidity sensor in my thermostat agrees. Based on comfort, I also agree. If the humidity were higher, 77F would feel too warm.

THe supply temp isn't 47. I haven't checked it recently, but it's probably in the low 50's. I run the airflow a little low and the ductwork is close to sweating with a dewpoint around 50F in the basement. Airflow is probably around 1200CFM on a 3.5 ton system, so around 350CFM/ton. When I use DoD, that drops about another 100CFM. So about But it does have a TXV and I believe part of the coil surface is getting that cool. Further, the supply temp on my upstairs Infinity probably is under 50F. With revserse stack effect, the upstairs does most of the dehumidification.

[Florida Joy]

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.

Just for kicks, I looked at the forecast for today's weather in Des Moines, Iowa. The outside RH today will range from a low of 25% to a high of 41%. Compare that to the outside RH for today at my place in Florida.... between 75% and 85%.

It sounds like opening the windows in Iowa would do as well as A/C in maintaining comfort... and with fresher air!