Ductwork

[tedkidd]

S Wall 36'/Windows 48sqft/R15
N Wall 36'/Windows 66sqft/R22
E Wall 44'/Windows 30sqft/28' R22/16' R15
W Wall 44'/Windows 65sqft/28' R22/16' R15

Window Values
U Value-0.28
SHGC-.18
R Value 3.57
Attic-R60
Ceiling of 1st floor over 2nd Floor R-30

I was in unbelief when I had the load calc performed.

My current AC is 2ton, 27 years old. I made it through this summer comfortable and it actually was leaking refrigerant.

The load calc also included my basement if that makes a difference.

Lol. "your 27 year old 2 ton works fine, so you really need a 4 ton because, well, my daughter needs braces"

44/14 split sounds suspicious. Intuition says heat load is high or cooling is low. Even 44/24 seems off, so maybe both are off. If you are getting a heat pump you'll be much happier with 2 stage given your apparent seasonal split.

[remodel80]

IF your SHGC is actually 0.18, I'd suspect that you _NOT_ may be able to see through them so-to-speak.
( in other words, darker than h_LL).

Please verify that value with a purchase order, window tag, vendor catalog or correspondence with the window mfg representative.

Dan,
I can see through them fine! I retrieved the value from the website of the manufacturer which is Integrity. Windows are there wood ultrex casement with LoE366

[remodel80]

Tedkidd,
What would your guess be?
And my plan was to go with a 95% 2 Stage ECM Furnace with 2 Stage 15 seer or better heat pump and use an ecobee thermostat
If i was going to size the unit I am thinking a 60,000-70,000 BTU with 3 Ton HP, but I am not HVAC technican and just a guy trying to educate himself to make sure my money is well spent.

[tedkidd]

Any sense how long your current furnace runs per hour on the coldest days?

Annual gas consumption?

Sounds like your replacement plan is good. Dict diagnostics wb nice, at least external static on current system. Want to be sure 1200 cfm works ok on your duct. (Udarrell can tell if it's definitely not off the top of his head).


Thought about getting ecobee now, replacing equipment in spring?

[remodel80]

No, havent run the furnace through the winter since I have done the addition. But currently with 40f evening temps runs less time than it takes to heat the exchanger up.
Gas usage is typically 500 gallons-Three year base, but this is also during remodel and improving envelope and insulation and windows but 1st year Heating 65F,2nd year 68F, 3rd year 72f. Last winter usage was 200 gallons but had considerably fair weather compared to 3 years before.

Duct is 18x16 for 12' 90's and reduces to 17x13 goes 11' 90's continues 17x13 10' 90's runs 15' end of main.
5-6 round, and 6-8 round off of this. Another line 12x8 10' with 3-6 round

Both main trunk lines come right off the coil box on each side.

Already have Ecobee, was planning to upgrade yet this year, I believe that the unit is not sized correctly and is costing me by not upgrading.

[dan sw fl]

Dan,
I can see through them fine! I retrieved the value from the website of the manufacturer which is Integrity. Windows are there wood ultrex casement with LoE366

I am now updated on Marvin Integrity Low E 366 which has SHGC 0.18 U-Value 0.28 and VT 0.41. [ reviewed Marvin website literature].
That means __ the windows Heat Gain is about 20% of a clear glass __ and saves about 12,000 BTU/hr / 1-ton + of cooling capacity.
+ along with VERY High R-value walls/ celing, the Manual J calculated heating/cooing requirments are MUCH Less than half of what one would normally expect.

[remodel80]

I am now updated on Marvin Integrity Low E 366 which has SHGC 0.18 U-Value 0.28 and VT 0.41. [ reviewed Marvin website literature].
That means __ the windows Heat Gain is about 20% of a clear glass __ and saves about 12,000 BTU/hr / 1-ton + of cooling capacity.
+ along with VERY High R-value walls/ celing, the Manual J calculated heating/cooing requirments are MUCH Less than half of what one would normally expect.

So now my manaul j calculation that seemed out of whack is in line? I appreciate your questioning Dan since it was striving to reveal the truth to the numbers.

I wish I could find a contractor locally that would do the quality job that you guys belief is standard.

[tedkidd]

If you never get within a mile of the line, its hard to see where the line is. They tell you where the line is but dont even know what the line looks like.

My buddy Randy had to SPECIFY what he wanted. And he had to go to a pretty sophisticated company. A year later the guys who said "that won't work" have been proven to be shovelling dogma.

Most HVAC guys don't want to deviate from what they've been doing because it takes them to uncertain places. Easier, safer, and much cheaper to make the same hamburger over and over than put thought into design of each one. Time is the thing the need to optimize, design and problems suck time unproductively.

Nobody wants to expose themselves to uncertain uncompensated time liabilities. This is completely understandable.

You may have to explain that by specifying, their risk actually GOES DOWN. They are accountable for a good job, and to warranty the equipment. Size issues are NOT their problem.

If you convey this effectively only the most dense should fail to grasp what a good deal this is.