Will a 90+ furnace use less fuel then an 80 YES.
But the return on investment needs to be looked at in 2 ways.
1 Your monthly expenses.
2 Your utility supplier.
The 3, 5 or 10% you save as a consumer is helpful but in the big picture if we don’t begin using less electricity and fossil fuels more power plants will have to be built. More pipelines will have to be laid. More wells dug.
This whole argument over 80% / 90+% is not about one house but your local utility company’s ability to continue supplying the consumer.
Why do you think A/C’s have to be 13%SEER.
There is a proposal to put a LNG storage ship in Long Island sound the size of the Queen Mary. Would you want this in your back yard. I don’t think so!
Think about it.
OPs question was life expectancy, i think a properly installed 90+ will last as long or longer than an 80%. manufacturers must also based on warranties that are given.
Hey jeep6275 & t527ed, thanks for the info on 90+ lifespans. That helps to offset the concerns about fan and circuitry problems - sure would be nice if all the companies would pony up a system on a "lifetime" warranty but obsolete system like that Amana, rather that a couple hundred bucks.
Any info anyone has on tax credits would be great, too. They will go into the cost justification.
Hey jultzya, I gotta build a spreadsheet to see what those heatpump figures might mean in my situation. I may take at least a passing glance at geothermal, too.
if considering a Heat Pump in your area you may want to consider one of these units.
I've never used one and likely will never need it here in Texas but may be of interrest in your area.
HVAC Contractor, Tyler Texas.
Ding, Ding, Ding, Ding, Ding, Ding, Ding....And the winner is Jultzya...by making the obvious statements!!!
TKO in my book!
MadeinUS you contradicted yourself in many, many, replies...you were doing a lot of bobbing & weaving but no knockout punch...sorry ya lost
Hey julytza, I've "absorbed" the heat pump info you posted (not sure how much of it leaked out, though).
I'm still trying to get a handle on how to figure operating costs, figuring out how often and how long the "switch-over" point where supplemental heating systems is needed would be reached. That could get REAL expensive on those couple of -10 degree nights we get here, but we only get 1 or 2 of those.
Also, you showed that the efficiency of a heat pump decreases with the outside temp, but doesn't the actual BTU output also drop? I guess that doesn't matter once you reach that "switch-over" point, but it probably affects where that point is, right? Are the efficiencies/outputs of these things at different temps known?
dpatty referred me to the Nyle Cold Climate Heat Pump (http://www.nyletherm.com/spaceheating.htm). Their BTU output seems to be optimized at 20 degrees rather than steadily dropping as the temp falls under 40 degrees, and still looks decent down at 0 degrees. Dunno if they are trailblazers or charlatans, though.
So, what is the next part of the lesson? Would I keep my 30 year old monster as a backup or pitch it and put in a air handler for the heat pump? I suspect I would need to bump up my main circuit box (which might justify putting in a separate meter instead). Hey, do people put a roof over these things to keep them from being buried during a blizzard?
I'll get to your questions, but do this for me...
Have you done a load calc on your home?
We need to know what the heat loss figure is, preferably at your low (5F) and (65F) degree (AT) outside temps.
I ask this as it has a direct effect on estimating your heating cost. If you haven't performed one, you can do so by clicking on the red tab above.
Find out what your heating requirements are and post them.
Items needed for cost comparisons include...
1) HDD (6569)
2) CDD (626)
3) Load requirements (needed)
4) Winter Stat setting (needed)
5) Equipment specifications (I have)
6) Fuel cost (.96/ccf Nat, .087/kw first 20kw/day .070/kw over)
7) Location (S/E MI., 30 north of D)
You lost the nitrogen battle to me.
Originally posted by madeinusa
Ok, I will have to follow up tomorrow. I need to write a speech for my 2000th post.
So until tomorrow, you guys figure out if you seriously want to lose another debate with me. Remember, I am undefeated here.
Edit: You are starting to use your mind grasshopper with the "it aint going out the chimney thinking". catch you guys tomorrow.
[Edited by madeinusa on 10-08-2005 at 03:32 AM]
How about the best of both worlds, go duel fuel.
HVAC Contractor, Tyler Texas.
Okay julytza, here are the load reqs from HVAC-Calc at this time:
56.840 BTU Heat Loss
22,921 BTU Heat Gain
Winter thermostat set at 70 during day, 65 at night.
Re HVAC-Calc: I had used some other programs/spreadsheets and they put the house heat loss in the 50-55KBTU range. HVAC-Calc was near 70KBTU with a big wall loss when I told it I had uninsulated block walls. I have concrete block walls with face brick - the face brick is 1/2" thick and mounted on a 1/2" fiberboard panel. Between that and the fact that the inside walls are a 1" thick drywall/mud/plaster layer I changed HVAC-Calc to use R-5 (1" insulation). It dropped the BTU requirement under 40KBTU that way, which seemed too low. I then selected 8" block + 4"brick uninsulated and got the figure I gave you.
Now, did I do OK, or is this a case of playing with the tool until you get the results you expect?
Another factor that can wildly skew the result is infiltration, which I left alone at .4/.7 (medium).
Is there anything I missed here?