Maybe. How well does it perform? To hot at times, too muggy at times?
By different, do you mean smaller or larger? Are you changing just coils
and condenser or changing the air handler also?
Unless you are absolutely sure it performs well as is, I'd try another
dealer and get the calculation done.
If you bought a higher efficiency system, you may need larger ducts
because I believe they need to push more air. That's what I've read
anyway. Don't feel bad, last time I had mine replaced I called three
people and none did a load calc. Next time I think I'll offer to pay
for the estimate if they'll do one and show their work.
I guess the best way is to just get the estimat first, then say you'll
sign it only if they do the load calculation. The estimate will
probably be overpriced anyway, so might as well get something extra out
Chris Hill wrote:
I guess I meant to say "quote". The next contractor coming out is
supposedly going to do the complete calculation for free and tell me
the result. He said they won't actually show you the calculations
though unless you sign the contract and go with them. Makes senses I
You said it is humid, so you just answered your own question. A VS unit
can be set on real low and pull out the most humidity, a Vsdc unit can
pull only 100-120 watts on low and be left on continously. but get the
RAJ, why do you care about seeing the actual calculations? If the end
result is that you need a furnace of XXXBTU, what difference does it
make how he got to that conclusion (or are you supposed to verify his
work?). If you were looking for more quotes you would then use the end
result to ensure that the other guys aren't off the mark, right?
So..what you are saying, if he gets a quote for $3000, one for $2500 and one
for $1000, then he should not care who actually did a load calc right?
Or..he gets 3 quotes for the same price.......but three diffent sized
units..he should just throw a freaking dart at the quotes right?
He needs to know who did the work, have them show him the calcs, and explain
how the calc, and the quote, compare, since there are times you will end up
rounding up, or down due to the final numbers.
Nope, that's not what I said.
The suggesting was that as long as the individual goes through the
process of doing the calculations then the result is what matters. At
the end of the day, unless they are completely incompetent they should
all come up with systems in the same area. If they don't (and claim
that they performed the calculations) then some of them are lying and
in this case, you wouldn't be able to tell who is lying until after you
signed with them.
But according to this guy (and you agreed with the result) he doesn't
get to see the calcs until after he's signed the work agreement. What
good are the numbers at that point?
Load Calcs are usually not necessary. Within 5 miles of me, there
are 10,000 homes built by the same 3 builders, each using 5 building
plans. Everyone in the hvac business knows exactly what size unit
these 5 plans require.
The only load calcs necessary are the 7 custom built 7 bedroom homes
that get built each year.
Do all these homes have exactly the same size units for the same
- No, of course not. Joe and his wife like to run their thermostat
at 60 degrees year around, even in 105 degree spells. Theirs is a 5
ton system while their friends have a 3 1/2 ton system.
All it takes is a brain and talking to your neighbor., not a load
calc - that will probably be inaccurate anyway.
Depends on the area in which you live. In a subdivision of new
construction I'd agree. The problem is that once houses get some age
on them they begin to vary. For example, there is one house in my
neighborhood like mine. It has the original windows in it, which are
probably not very efficient. It has the original siding on it as
well. Nobody has even thought to plant trees to shade it and possibly
reduce the cooling load. In about ten years my house won't need near
as much cooling as my neighbor's will.
Very good info right there. In fact all the HVAC companies that have
given me estimates on my new estimate (except the one guy) all sized
furnaces in the same BTU range based on square footage of the house and
existing duct work. These guys know what these homes are like and what
it takes to heat/cool them. Yes, they could spend 30 minutes or more
doing a load calc but unless they know EXACTLY how the house is built
(wall/window R rating, etc), that information may be innacurate...as
the saying goes "garbage in..garbage out".
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